EXHIBIT 1.1

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                                  NANOSYS, INC.

                            (a Delaware corporation)

                        6,250,000 Shares of Common Stock

                               PURCHASE AGREEMENT

                             Dated: _________, 2004

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                                  NANOSYS, INC.

                            (a Delaware corporation)

                        6,250,000 Shares of Common Stock

                          (Par Value $0.001 Per Share)

                               PURCHASE AGREEMENT

                                                                  ________, 2004

MERRILL LYNCH & CO.
Merrill Lynch, Pierce, Fenner & Smith
            Incorporated

Lehman Brothers Inc.
CIBC World Markets Corp.
Needham & Company, Inc.
as Representatives of the several Underwriters
c/o      Merrill Lynch & Co.
         Merrill Lynch, Pierce, Fenner & Smith
                      Incorporated
4 World Financial Center
New York, New York  10080

Ladies and Gentlemen:

      Nanosys, Inc., a Delaware corporation (the "Company") confirms its
respective agreements with Merrill Lynch & Co., Merrill Lynch, Pierce, Fenner &
Smith Incorporated ("Merrill Lynch") and each of the other Underwriters named in
Schedule A hereto (collectively, the "Underwriters", which term shall also
include any underwriter substituted as hereinafter provided in Section 10
hereof), for whom Merrill Lynch and Lehman Brothers Inc. CIBC World Markets
Corp. and Needham & Company, Inc. are acting as representatives (in such
capacity, the "Representatives"), with respect to (i) the sale by the Company
and the purchase by the Underwriters, acting severally and not jointly, of the
respective numbers of shares of Common Stock, par value $0.001 per share, of the
Company ("Common Stock") set forth in Schedule A hereto and (ii) the grant by
the Company to the Underwriters, acting severally and not jointly, of the option
described in Section 2(b) hereof to purchase all or any part of 937,500
additional shares of Common Stock to cover overallotments, if any. The aforesaid
6,250,000 shares of Common Stock (the "Initial Securities") to be purchased by
the Underwriters and all or any part of the 937,500 shares of Common Stock
subject to the option described in Section 2(b) hereof (the "Option Securities")
are hereinafter called, collectively, the "Securities".

      The Company understands that the Underwriters propose to make a public
offering of the Securities as soon as the Representatives deem(s) advisable
after this Agreement has been executed and delivered.

      The Company and the Underwriters agree that up to 312,500 shares of the
Securities to be purchased by the Underwriters (the "Reserved Securities") shall
be reserved for sale by the Underwriters to certain eligible employees and
persons having business relationships with the Company (the "Invitees"), as part
of the distribution of the Securities by the Underwriters, subject to the terms
of this Agreement, the applicable rules, regulations and interpretations of the
National Association of Securities



Dealers, Inc. (the "NASD") and all other applicable laws, rules and regulations.
To the extent that such Reserved Securities are not orally confirmed for
purchase by Invitees by the end of the first business day after the date of this
Agreement, such Reserved Securities may be offered to the public as part of the
public offering contemplated hereby.

      The Company has filed with the Securities and Exchange Commission (the
"Commission") a registration statement on Form S-1 (No. 333-114735), including
the related preliminary prospectus or prospectuses, covering the registration of
the Securities under the Securities Act of 1933, as amended (the "1933 Act").
Promptly after execution and delivery of this Agreement, the Company will
prepare and file a prospectus in accordance with the provisions of Rule 430A
("Rule 430A") of the rules and regulations of the Commission under the 1933 Act
(the "1933 Act Regulations") and paragraph (b) of Rule 424 ("Rule 424(b)") of
the 1933 Act Regulations. The information included in such prospectus that was
omitted from such registration statement at the time it became effective but
that is deemed to be part of such registration statement at the time it became
effective pursuant to paragraph (b) of Rule 430A is referred to as "Rule 430A
Information." Each prospectus used before such registration statement became
effective, and any prospectus that omitted the Rule 430A Information, that was
used after such effectiveness and prior to the execution and delivery of this
Agreement, is herein called a "preliminary prospectus." Such registration
statement, including the exhibits and any schedules thereto, at the time it
became effective, and including the Rule 430A Information, is herein called the
"Registration Statement." Any registration statement filed or to be filed
pursuant to Rule 462(b) of the 1933 Act Regulations is herein referred to as the
"Rule 462(b) Registration Statement," and after such filing the term
"Registration Statement" shall include the Rule 462(b) Registration Statement.
The final prospectus in the form first furnished to the Underwriters for use in
connection with the offering of the Securities is herein called the
"Prospectus." For purposes of this Agreement, all references to the Registration
Statement, any preliminary prospectus, the Prospectus or any amendment or
supplement to any of the foregoing shall be deemed to include the copy filed
with the Commission pursuant to its Electronic Data Gathering, Analysis and
Retrieval system ("EDGAR").

      SECTION 1. Representations and Warranties.

      (a) Representations and Warranties by the Company. The Company represents
and warrants to each Underwriter as of the date hereof, as of the Closing Time
referred to in Section 2(c) hereof, and as of each Date of Delivery (if any)
referred to in Section 2(b) hereof, and agrees with each Underwriter, as
follows:

            (i) Compliance with Registration Requirements. Each of the
      Registration Statement, any Rule 462(b) Registration Statement and any
      post-effective amendment thereto has become effective under the 1933 Act
      and no stop order suspending the effectiveness of the Registration
      Statement, any Rule 462(b) Registration Statement or any post-effective
      amendment thereto has been issued under the 1933 Act and no proceedings
      for that purpose have been instituted or are pending or, to the knowledge
      of the Company, are contemplated by the Commission, and any request on the
      part of the Commission for additional information has been complied with.

            At the respective times the Registration Statement, any Rule 462(b)
      Registration Statement and any post-effective amendments thereto became
      effective and at the Closing Time (and, if any Option Securities are
      purchased, at the Date of Delivery), the Registration Statement, the Rule
      462(b) Registration Statement and any amendments and supplements thereto
      complied and will comply in all material respects with the requirements of
      the 1933 Act and the 1933 Act Regulations and did not and will not contain
      an untrue statement of a material fact or omit to state a material fact
      required to be stated therein or necessary to make the statements therein
      not

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      misleading, and the Prospectus, any preliminary prospectus and any
      supplement thereto or prospectus wrapper prepared in connection therewith,
      at their respective times of issuance and at the Closing Time, complied
      and will comply in all material respects with any applicable laws or
      regulations of foreign jurisdictions in which the Prospectus and such
      preliminary prospectus, as amended or supplemented, if applicable, are
      distributed in connection with the offer and sale of Reserved Securities.
      Neither the Prospectus nor any amendments or supplements thereto
      (including any prospectus wrapper), at the time the Prospectus or any such
      amendment or supplement was issued and at the Closing Time (and, if any
      Option Securities are purchased, at the Date of Delivery), included or
      will include an untrue statement of a material fact or omitted or will
      omit to state a material fact necessary in order to make the statements
      therein, in the light of the circumstances under which they were made, not
      misleading. The representations and warranties in this subsection shall
      not apply to statements in or omissions from the Registration Statement or
      Prospectus made in reliance upon and in conformity with written
      information furnished to the Company by any Underwriter through Merrill
      Lynch expressly for use in the Registration Statement (or any amendment
      thereto) or the Prospectus (or any amendment or supplement thereto).

            Each preliminary prospectus and the prospectus filed as part of the
      Registration Statement as originally filed or as part of any amendment
      thereto complied when so filed in all material respects with the 1933 Act
      Regulations and each preliminary prospectus and the Prospectus delivered
      to the Underwriters for use in connection with this offering was identical
      to the electronically transmitted copies thereof filed with the Commission
      pursuant to EDGAR, except to the extent permitted by Regulation S-T.

            (ii) Independent Accountants. The accountants who certified the
      financial statements and supporting schedules included in the Registration
      Statement are independent public accountants as required by the 1933 Act
      and the 1933 Act Regulations.

            (iii) Financial Statements. The financial statements included in the
      Registration Statement and the Prospectus, together with the related
      schedules and notes, present fairly the financial position of the Company
      at the dates indicated and the statement of operations, stockholders'
      equity and cash flows of the Company for the periods specified; said
      financial statements have been prepared in conformity with generally
      accepted accounting principles ("GAAP") applied on a consistent basis
      throughout the periods involved. The supporting schedules included in the
      Registration Statement present fairly in accordance with GAAP the
      information required to be stated therein. The selected financial data and
      the summary financial information included in the Prospectus present
      fairly the information shown therein and have been compiled on a basis
      consistent with that of the audited financial statements included in the
      Registration Statement. No other financial statements and supporting
      schedules are required to be included in the Registration Statement.

            (iv) No Material Adverse Change in Business. Since the respective
      dates as of which information is given in the Registration Statement and
      the Prospectus, except as otherwise stated therein, (A) there has been no
      material adverse change in the condition, financial or otherwise, or in
      the earnings, business affairs or business prospects of the Company,
      whether or not arising in the ordinary course of business (a "Material
      Adverse Effect"), (B) there have been no transactions entered into by the
      Company, other than those in the ordinary course of business, which are
      material with respect to the Company, and (C) there has been no dividend
      or distribution of any kind declared, paid or made by the Company on any
      class of its capital stock.

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            (v) Good Standing of the Company. The Company has been duly
      organized and is validly existing as a corporation in good standing under
      the laws of the State of Delaware and has corporate power and authority to
      own, lease and operate its properties and to conduct its business as
      described in the Prospectus and to enter into and perform its obligations
      under this Agreement; and the Company is duly qualified as a foreign
      corporation to transact business and is in good standing in each other
      jurisdiction in which such qualification is required, whether by reason of
      the ownership or leasing of property or the conduct of business, except
      where the failure so to qualify or to be in good standing would not result
      in a Material Adverse Effect.

            (vi) Subsidiaries. The Company has no subsidiaries.

            (vii) Capitalization. The authorized, issued and outstanding
      capitalization of the Company was as set forth in the Prospectus under the
      "Actual" column under the caption "Capitalization" as of the date set
      forth therein and there have not been any subsequent changes, other than
      as set forth in the Prospectus, to the authorized, issued and outstanding
      capitalization of the Company, except for subsequent issuances, if any,
      pursuant to this Agreement or employee benefit plans described in the
      Prospectus. The shares of issued and outstanding capital stock have been
      duly authorized and validly issued and are fully paid and non-assessable;
      none of the outstanding shares of capital stock was issued in violation of
      the preemptive or other similar rights of any securityholder of the
      Company.

            (viii) Authorization of Agreement. This Agreement has been duly
      authorized, executed and delivered by the Company.

            (ix) Authorization and Description of Securities. The Securities to
      be purchased by the Underwriters from the Company have been duly
      authorized for issuance and sale to the Underwriters pursuant to this
      Agreement and, when issued and delivered by the Company pursuant to this
      Agreement against payment of the consideration set forth herein, will be
      validly issued and fully paid and non-assessable; the Common Stock
      conforms to all statements relating thereto contained in the Prospectus
      and such description conforms to the rights set forth in the instruments
      defining the same; and the issuance of the Securities is not subject to
      the preemptive or other similar rights of any securityholder of the
      Company, which has not been validly waived.

            (x) Absence of Defaults and Conflicts. The Company is not in
      violation of its charter or bylaws or in default in the performance or
      observance of any obligation, agreement, covenant or condition contained
      in any material contract, indenture, mortgage, deed of trust, loan or
      credit agreement, note, lease or other agreement or instrument to which
      the Company is a party or by which it or any of them may be bound, or to
      which any of the property or assets of the Company is subject
      (collectively, "Agreements and Instruments") except for such defaults that
      would not result in a Material Adverse Effect; and the execution, delivery
      and performance of this Agreement and the consummation of the transactions
      contemplated herein and in the Registration Statement (including the
      issuance and sale of the Securities and the use of the proceeds from the
      sale of the Securities as described in the Prospectus under the caption
      "Use of Proceeds") and compliance by the Company with its obligations
      hereunder have been duly authorized by all necessary corporate action and
      do not and will not, whether with or without the giving of notice or
      passage of time or both, conflict with or constitute a breach of, or
      default or Repayment Event (as defined below) under, or result in the
      creation or imposition of any lien, charge or encumbrance upon any
      property or assets of the Company pursuant to, the Agreements and
      Instruments (except for such conflicts, breaches, defaults or Repayment
      Events or liens, charges or encumbrances that would not result in a
      Material Adverse Effect), nor will such action result in any violation of
      the provisions of the charter or bylaws of the Company or any applicable
      law,

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      statute, rule, regulation, judgment, order, writ or decree of any
      government, government instrumentality or court, domestic or foreign,
      having jurisdiction over the Company or any of its assets, properties or
      operations. As used herein, a "Repayment Event" means any event or
      condition which gives the holder of any note, debenture or other evidence
      of indebtedness (or any person acting on such holder's behalf) the right
      to require the repurchase, redemption or repayment of all or a portion of
      such indebtedness by the Company.

            (xi) Absence of Labor Dispute. No labor dispute with the employees
      of the Company exists or, to the knowledge of the Company, is imminent,
      and the Company is not aware of any existing or imminent labor disturbance
      by the employees of any of its principal suppliers, manufacturers,
      customers or contractors, which, in either case, would result in a
      Material Adverse Effect.

            (xii) Absence of Proceedings. There is no action, suit, proceeding,
      inquiry or investigation before or brought by any court or governmental
      agency or body, domestic or foreign, now pending, or, to the knowledge of
      the Company, threatened, against or affecting the Company, which might
      result in a Material Adverse Effect, or which might materially and
      adversely affect the properties or assets of the Company or the
      consummation of the transactions contemplated in this Agreement or the
      performance by the Company of its obligations hereunder; the aggregate of
      all pending legal or governmental proceedings to which the Company is a
      party or of which any of its property or assets is the subject which are
      not described in the Registration Statement, including ordinary routine
      litigation incidental to the business, could not reasonably be expected to
      result in a Material Adverse Effect.

            (xiii) Accuracy of Exhibits. There are no contracts or documents
      which are required to be described in the Registration Statement or the
      Prospectus or to be filed as exhibits thereto which have not been so
      described and filed as required by Item 601, Regulation S-K.

            (xiv) Descriptions. The statements set forth in the Registration
      Statement or the Prospectus under the caption "Description of Capital
      Stock," insofar as they purport to constitute a summary of the terms of
      the Securities, under the caption "Business -- Collaborative
      Arrangements," insofar as they purport to describe the provisions of
      agreements or arrangements referred to therein, under the caption
      "Business -- Patents and Other Intellectual Property," insofar as they
      purport to describe the Company's Intellectual Property and under the
      caption "Material United States Federal Tax Consequences for Non-United
      States Holders," insofar as they describe provisions of the laws and
      regulations referred to therein, are accurate descriptions or summaries in
      all material respects.

            (xv) Possession of Intellectual Property. The Company owns or
      possesses, or can acquire on reasonable terms, adequate patents, patent
      rights, licenses, inventions, copyrights, know-how (including trade
      secrets and other unpatented and/or unpatentable proprietary or
      confidential information, systems or procedures), trademarks, service
      marks, trade names or other intellectual property (collectively,
      "Intellectual Property") necessary or used in any material respect to
      carry on the business now operated by them and in the manner in which it
      is contemplated as set forth in the Prospectus. None of the patents owned
      by the Company are unenforceable or invalid and, to the Company's
      knowledge, the parties from which the Company has licensed patents are
      prosecuting those patents in a manner that is consistent with standard
      practices for similarly situated licensors. The Company has not received
      any notice or is otherwise aware of any infringement of or conflict with
      asserted rights of others with respect to any Intellectual Property or of
      any facts or circumstances which would render any Intellectual Property
      invalid or inadequate to protect the interest of the Company therein, and
      which

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      infringement or conflict (if the subject of any unfavorable decision,
      ruling or finding) or invalidity or inadequacy, singly or in the
      aggregate, would result in a Material Adverse Effect. Other than as
      disclosed in the Prospectus, there are no pending or threatened actions,
      suits, proceedings or claims by others that the Company is infringing any
      patent, trade secret, trade mark, service mark, copyright or other
      intellectual property or proprietary right of any third party. Other than
      as disclosed in the Prospectus, the Company is not obligated to pay a
      material royalty, grant a material license or provide material
      consideration to any third party in connection with the Company's
      Intellectual Property. Other than as disclosed in the Prospectus, no third
      party, including any academic or governmental organization, possesses
      rights to the Company's Intellectual Property which, if exercised, would
      result in a Material Adverse Effect or enable such third party to develop
      products competitive to those of the Company.

            (xvi) Absence of Further Requirements. No filing with, or
      authorization, approval, consent, license, order, registration,
      qualification or decree of, any court or governmental authority or agency
      is necessary or required for the performance by the Company of its
      obligations hereunder, in connection with the offering, issuance or sale
      of the Securities hereunder or the consummation of the transactions
      contemplated by this Agreement, except (i) such as have been already
      obtained or as may be required under the 1933 Act or the 1933 Act
      Regulations or state securities laws and (ii) such as have been obtained
      under the laws and regulations of jurisdictions outside the United States
      in which the Reserved Securities are offered.

            (xvii) Absence of Manipulation. Neither the Company nor any
      affiliate of the Company has taken, nor will the Company or any affiliate
      take, directly or indirectly, any action which is designed to or which has
      constituted or which would be expected to cause or result in stabilization
      or manipulation of the price of any security of the Company to facilitate
      the sale or resale of the Securities.

            (xviii) Possession of Licenses and Permits. The Company possesses
      such permits, licenses, approvals, consents and other authorizations
      (collectively, "Governmental Licenses") issued by the appropriate federal,
      state, local or foreign regulatory agencies or bodies necessary to conduct
      the business now operated by it, except where the failure so to possess
      would not, singly or in the aggregate, result in a Material Adverse
      Effect; the Company is in compliance with the terms and conditions of all
      such Governmental Licenses, except where the failure so to comply would
      not, singly or in the aggregate, result in a Material Adverse Effect; all
      of the Governmental Licenses are valid and in full force and effect,
      except when the invalidity of such Governmental Licenses or the failure of
      such Governmental Licenses to be in full force and effect would not,
      singly or in the aggregate, result in a Material Adverse Effect; and the
      Company has not received any notice of proceedings relating to the
      revocation or modification of any such Governmental Licenses which, singly
      or in the aggregate, if the subject of an unfavorable decision, ruling or
      finding, would result in a Material Adverse Effect.

            (xix) Title to Property. The Company owns no real property. The
      Company has good and marketable title to all personal property owned by
      the Company, in each case, free and clear of all mortgages, pledges,
      liens, security interests, claims, restrictions or encumbrances of any
      kind except such as (a) are described in the Prospectus or (b) do not,
      singly or in the aggregate, materially affect the value of such property
      and do not interfere with the use made and proposed to be made of such
      property by the Company; and all of the leases and subleases material to
      the business of the Company, and under which the Company holds properties
      described in the Prospectus, are in full force and effect, and the Company
      has not received any notice of any material claim of any sort that has
      been asserted by anyone adverse to the rights of the Company under any of
      the leases or subleases mentioned above, or affecting or questioning the
      rights of the

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      Company to the continued possession of the leased or subleased premises
      under any such lease or sublease.

            (xx) Investment Company Act. The Company is not required, and upon
      the issuance and sale of the Securities as herein contemplated and the
      application of the net proceeds therefrom as described in the Prospectus
      will not be required, to register as an "investment company" under the
      Investment Company Act of 1940, as amended (the "1940 Act").

            (xxi) Environmental Laws. Except as described in the Registration
      Statement and except as would not, singly or in the aggregate, result in a
      Material Adverse Effect, (A) the Company is not in violation of any
      federal, state, local or foreign statute, law, rule, regulation,
      ordinance, code, policy or rule of common law or any judicial or
      administrative interpretation thereof, including any judicial or
      administrative order, consent, decree or judgment, relating to pollution
      or protection of human health, the environment (including, without
      limitation, ambient air, surface water, groundwater, land surface or
      subsurface strata) or wildlife, including, without limitation, laws and
      regulations relating to the release or threatened release of chemicals,
      pollutants, contaminants, wastes, toxic substances, hazardous substances,
      petroleum or petroleum products, asbestos-containing materials or mold
      (collectively, "Hazardous Materials") or to the manufacture, processing,
      distribution, use, treatment, storage, disposal, transport or handling of
      Hazardous Materials (collectively, "Environmental Laws"), (B) there are no
      pending or, to the Company 's knowledge, threatened administrative,
      regulatory or judicial actions, suits, demands, demand letters, claims,
      liens, notices of noncompliance or violation, investigation or proceedings
      relating to any Environmental Law against the Company and (C) to the
      Company's knowledge, there are no events or circumstances that would
      reasonably be expected to form the basis of an order for clean-up or
      remediation, or an action, suit or proceeding by any private party or
      governmental body or agency, against or affecting the Company relating to
      Hazardous Materials or any Environmental Laws. In the ordinary course of
      its business, the Company has reviewed the effect of Environmental Laws on
      the business, operations and properties of the Company, (including,
      without limitation, the identification and evaluation of any capital or
      operating expenditures required for clean-up of properties or compliance
      with Environmental Laws or any permit, license or approval, any related
      constraints on operating activities and any potential liabilities to third
      parties).

            (xxii) Registration Rights. Other than as described in the
      Prospectus, there are no persons with registration rights or other similar
      rights to have any securities registered pursuant to the Registration
      Statement or otherwise registered by the Company under the 1933 Act,
      except such rights as have been validly waived.

            (xxiii) Reserved Shares. The Company has not offered, or caused the
      Underwriters to offer, Reserved Shares to any person with the specific
      intent to unlawfully influence (i) a partner, customer or supplier of the
      Company to alter the partner's, customer's or supplier's level or type of
      business with the Company, or (ii) a trade journalist or publication to
      write or publish favorable information about the Company.

            (xxiv) Insurance. The Company carries, or is covered by, insurance
      covering risks that are material to the Company in such amounts and
      covering such risks as is adequate for the conduct of its businesses and
      the value of its properties and as is customary for companies that are
      similarly situated and engaged in similar businesses in similar
      industries; the Company has not been refused any insurance coverage sought
      or applied for; and the Company has no reason to believe it will not be
      able to renew its existing insurance coverage as and when such coverage

                                       7


      expires or to obtain similar coverage from similar insurers as may be
      necessary to continue its business at a similar cost as its existing
      insurance policies.

            (xxv) Conversion of Preferred Stock. Pursuant to the terms of the
      Company's certificate of incorporation as in existence immediately prior
      to the Closing Time, immediately prior to the Closing Time, all shares of
      the Company's preferred stock issued and outstanding immediately prior to
      the sale of the Initial Shares shall automatically convert into shares of
      Common Stock.

            (xxvi) Disclosure Controls. The Company has established and
      maintains disclosure controls and procedures (as such term is defined in
      Rules 13a-15(e) and 15d-15(e) of the Exchange Act), which (i) are designed
      to ensure that material information required to be disclosed by the
      Company in reports that it will file or submit under the Exchange Act is
      made known to the Company's principal executive officer and principal
      financial officer by others within the Company, (ii) are designed to
      provide a reasonable assurance regarding the reliability of financial
      reporting and the preparation of financial statements for external
      purposes in accordance with generally accepted accounting principles and
      (iii) are effective in all material respects to perform the functions for
      which they were established. There are no significant deficiencies or
      material weaknesses in the design or operation of internal control over
      financial reporting which are reasonably likely to adversely affect the
      Company's ability to record, process, summarize and report financial
      information and, to the knowledge of the Company, no fraud, whether or not
      material, that involves or involved management or other employees who have
      a significant role in the Company's internal control over financial
      reporting.

            (xxvii) Accounting Controls. The Company maintains a system of
      internal accounting controls sufficient to provide reasonable assurance
      that (i) transactions are executed in accordance with management's general
      or specific authorizations, (ii) transactions are recorded as necessary to
      permit preparation of financial statements in conformity with generally
      accepted accounting principles and to maintain asset accountability, (iii)
      access to assets is permitted only in accordance with management's general
      or specific authorization and (iv) the recorded accountability for assets
      is compared with the existing assets at reasonable intervals and
      appropriate action is taken with respect to any differences.

            (xxviii) Off-Balance Sheet Transactions. Except as described in the
      Prospectus, there are no material off-balance sheet transactions,
      arrangements, obligations (including contingent obligations), or any other
      relationships with unconsolidated entities or other persons, that may have
      a material current or future effect on the Company's financial condition,
      changes in financial condition, results of operations, liquidity, capital
      expenditures, capital resources, or significant components of revenues or
      expenses.

            (xxix) No Association with NASD. There are no affiliations or
      associations (within the meaning of Article I (dd) of the Bylaws of the
      NASD) between any member of the NASD and any of the Company's officers or
      directors or, to the Company's knowledge, stockholders that own at least
      five percent of the aggregate number of outstanding shares of Common Stock
      or any beneficial owner of the Company's unregistered equity securities
      that were acquired during the 180-day period immediately preceding the
      initial filing date of the Registration Statement.

            (xxx) ERISA. The Company is in compliance in all material respects
      with all presently applicable provisions of the Employee Retirement Income
      Security Act of 1974, as amended, including the regulations and published
      interpretations thereunder ("ERISA"); no "reportable event" (as defined in
      ERISA) has occurred with respect to any "pension plan" (as defined in

                                        8


      ERISA) for which the Company would be likely to have any liability; the
      Company has not incurred and does not expect to incur liability under (i)
      Title IV of ERISA with respect to termination of, or withdrawal from, any
      "pension plan" or (ii) Sections 412 or 4971 of the Code; and each "pension
      plan" for which the Company would have any liability that is intended to
      be qualified under Section 401(a) of the Code is so qualified in all
      material respects and nothing has occurred, whether by action or by
      failure to act, which would cause the loss of such qualification.

            (xxxi) Sales of Common Stock. Except as described in the
      Registration Statement, the Company has not sold or issued any shares of
      Common Stock during the six-month period preceding the date of the
      Prospectus, including any sales pursuant to Rule 144A under, or
      Regulations D or S of, the Securities Act, other than shares issued
      pursuant to employee benefit plans, stock options plans or other employee
      compensation plans or pursuant to outstanding options, rights or warrants.

            (xxxii) Taxes. The Company has filed all federal, state and local
      income and franchise tax returns required to be filed through the date
      hereof and has paid all taxes due thereon, and no tax deficiency has been
      determined adversely to the Company which has had (nor does the Company
      have any knowledge of any tax deficiency which, if determined adversely to
      the Company would reasonably be expected to have) a Material Adverse
      Effect.

      (b) Officer's Certificates. Any certificate signed by any officer of the
Company delivered to the Representatives or to counsel for the Underwriters
shall be deemed a representation and warranty by the Company to each Underwriter
as to the matters covered thereby.

      SECTION 2. Sale and Delivery to Underwriters; Closing.

      (a) Initial Securities. On the basis of the representations and warranties
herein contained and subject to the terms and conditions herein set forth, the
Company agrees to sell to each Underwriter, severally and not jointly, and each
Underwriter, severally and not jointly, agrees to purchase from the Company at
the price per share set forth in Schedule B, that proportion of the number of
Initial Securities set forth in Schedule A opposite the name of such
Underwriter, plus any additional number of Initial Securities which such
Underwriter may become obligated to purchase pursuant to the provisions of
Section 10 hereof, bears to the total number of Initial Securities, subject, in
each case, to such adjustments among the Underwriters as the Representatives in
their sole discretion shall make to eliminate any sales or purchases of
fractional securities.

      (b) Option Securities. In addition, on the basis of the representations
and warranties herein contained and subject to the terms and conditions herein
set forth, the Company hereby grants an option to the Underwriters, severally
and not jointly, to purchase up to an additional 937,500 shares of Common Stock,
at the price per share set forth in Schedule B, less an amount per share equal
to any dividends or distributions declared by the Company and payable on the
Initial Securities but not payable on the Option Securities. The option hereby
granted will expire 30 days after the date hereof and may be exercised in whole
or in part from time to time only for the purpose of covering overallotments
which may be made in connection with the offering and distribution of the
Initial Securities upon notice by Merrill Lynch to the Company setting forth the
number of Option Securities as to which the several Underwriters are then
exercising the option and the time and date of payment and delivery for such
Option Securities. Any such time and date of delivery (a "Date of Delivery")
shall be determined by Merrill Lynch, but shall not be later than seven full
business days after the exercise of said option, nor in any event prior to the
Closing Time, as hereinafter defined. If the option is exercised as to all or
any portion of the Option Securities, each of the Underwriters, acting severally
and not jointly, will purchase that proportion of the total number of Option
Securities then being purchased which the number of Initial Securities set forth
in

                                       9


Schedule A opposite the name of such Underwriter bears to the total number of
Initial Securities, subject in each case to such adjustments as Merrill Lynch in
its discretion shall make to eliminate any sales or purchases of fractional
shares.

      (c) Payment. Payment of the purchase price for, and delivery of
certificates for, the Initial Securities shall be made at the offices of Latham
& Watkins LLP, 135 Commonwealth Drive, Menlo Park, California 94025-1105, or at
such other place as shall be agreed upon by the Representatives and the Company
at 9:00 A.M. (Eastern time) on the third (fourth, if the pricing occurs after
4:30 P.M. (Eastern time) on any given day) business day after the date hereof
(unless postponed in accordance with the provisions of Section 10), or such
other time not later than ten business days after such date as shall be agreed
upon by the Representatives and the Company (such time and date of payment and
delivery being herein called "Closing Time").

      In addition, in the event that any or all of the Option Securities are
purchased by the Underwriters, payment of the purchase price for, and delivery
of certificates for, such Option Securities shall be made at the above-mentioned
offices, or at such other place as shall be agreed upon by the Representatives
and the Company, on each Date of Delivery as specified in the notice from the
Representatives to the Company.

      Payment shall be made to the Company by wire transfer of immediately
available funds to a bank account designated by the Company against delivery to
the Representatives for the respective accounts of the Underwriters of
certificates for the Securities to be purchased by them. It is understood that
each Underwriter has authorized the Representatives, for its account, to accept
delivery of, receipt for, and make payment of the purchase price for, the
Initial Securities and the Option Securities, if any, which it has agreed to
purchase. Merrill Lynch, individually and not as representative of the
Underwriters, may (but shall not be obligated to) make payment of the purchase
price for the Initial Securities or the Option Securities, if any, to be
purchased by any Underwriter whose funds have not been received by the Closing
Time or the relevant Date of Delivery, as the case may be, but such payment
shall not relieve such Underwriter from its obligations hereunder.

      (d) Denominations; Registration. Certificates for the Initial Securities
and the Option Securities, if any, shall be in such denominations and registered
in such names as the Representatives may request in writing at least one full
business day before the Closing Time or the relevant Date of Delivery, as the
case may be. Unless the Representatives request electronic deposit of the
Securities, the certificates for the Initial Securities and the Option
Securities, if any, will be made available for examination and packaging by the
Representatives in The City of New York not later than 10:00 A.M. (Eastern time)
on the business day prior to the Closing Time or the relevant Date of Delivery,
as the case may be.

      SECTION 3. Covenants of the Company. The Company covenants with each
Underwriter as follows:

      (a) Compliance with Securities Regulations and Commission Requests. The
Company, subject to Section 3(b), will comply with the requirements of Rule 430A
or Rule 434, as applicable, and will notify the Representatives immediately, and
confirm the notice in writing, (i) when any post-effective amendment to the
Registration Statement shall become effective, or any supplement to the
Prospectus or any amended Prospectus shall have been filed, (ii) of the receipt
of any comments from the Commission, (iii) of any request by the Commission for
any amendment to the Registration Statement or any amendment or supplement to
the Prospectus or for additional information, and (iv) of the issuance by the
Commission of any stop order suspending the effectiveness of the Registration
Statement or of any order preventing or suspending the use of any preliminary
prospectus, or of the suspension of the qualification of the Securities for
offering or sale in any jurisdiction, or of the initiation of or, upon becoming
aware of

                                       10


such, any threat of proceedings for any such purposes. The Company will promptly
effect the filings necessary pursuant to Rule 424(b) and will take such steps as
it deems necessary to ascertain promptly whether the form of prospectus
transmitted for filing under Rule 424(b) was received for filing by the
Commission and, in the event that it was not, it will promptly file such
prospectus. The Company will make every reasonable effort to prevent the
issuance of any stop order and, if any stop order is issued, to obtain the
lifting thereof at the earliest possible moment.

      (b) Filing of Amendments. The Company will give the Representatives notice
of its intention to file or prepare any amendment to the Registration Statement
(including any filing under Rule 462(b)) or any amendment, supplement or
revision to either the prospectus included in the Registration Statement at the
time it became effective or to the Prospectus, will furnish the Representatives
with copies of any such documents a reasonable amount of time prior to such
proposed filing or use, as the case may be, and will not file or use any such
document to which the Representatives or counsel for the Underwriters shall
object.

      (c) Delivery of Registration Statements. The Company has furnished or will
deliver to the Representatives and counsel for the Underwriters, without charge,
signed copies of the Registration Statement as originally filed and of each
amendment thereto (including exhibits filed therewith or incorporated by
reference therein) and signed copies of all consents and certificates of
experts, and will also deliver to the Representatives, without charge, a
conformed copy of the Registration Statement as originally filed and of each
amendment thereto (without exhibits) for each of the Underwriters. The copies of
the Registration Statement and each amendment thereto furnished to the
Underwriters will be identical to the electronically transmitted copies thereof
filed with the Commission pursuant to EDGAR, except to the extent permitted by
Regulation S-T.

      (d) Delivery of Prospectuses. The Company has delivered to each
Underwriter, without charge, as many copies of each preliminary prospectus as
such Underwriter reasonably requested, and the Company hereby consents to the
use of such copies for purposes permitted by the 1933 Act. The Company will
furnish to each Underwriter, without charge, during the period when the
Prospectus is required to be delivered under the 1933 Act, such number of copies
of the Prospectus (as amended or supplemented) as such Underwriter may
reasonably request. The Prospectus and any amendments or supplements thereto
furnished to the Underwriters will be identical to the electronically
transmitted copies thereof filed with the Commission pursuant to EDGAR, except
to the extent permitted by Regulation S-T.

      (e) Continued Compliance with Securities Laws. The Company will comply
with the 1933 Act and the 1933 Act Regulations so as to permit the completion of
the distribution of the Securities as contemplated in this Agreement and in the
Prospectus. If at any time when a prospectus is required by the 1933 Act to be
delivered in connection with sales of the Securities, any event shall occur or
condition shall exist as a result of which it is necessary, in the opinion of
counsel for the Underwriters or for the Company, to amend the Registration
Statement or amend or supplement the Prospectus in order that the Prospectus
will not include any untrue statements of a material fact or omit to state a
material fact necessary in order to make the statements therein not misleading
in the light of the circumstances existing at the time it is delivered to a
purchaser, or if it shall be necessary, in the opinion of such counsel, at any
such time to amend the Registration Statement or amend or supplement the
Prospectus in order to comply with the requirements of the 1933 Act or the 1933
Act Regulations, the Company will promptly prepare and file with the Commission,
subject to Section 3(b), such amendment or supplement as may be necessary to
correct such statement or omission or to make the Registration Statement or the
Prospectus comply with such requirements, and the Company will furnish to the
Underwriters such number of copies of such amendment or supplement as the
Underwriters may reasonably request.

                                       11


      (f) Blue Sky Qualifications. The Company will use its best efforts, in
cooperation with the Underwriters, to qualify the Securities for offering and
sale under the applicable securities laws of such states and other jurisdictions
(domestic or foreign) as the Representatives may designate and to maintain such
qualifications in effect for a period of not less than one year from the later
of the effective date of the Registration Statement and any Rule 462(b)
Registration Statement; provided, however, that the Company shall not be
obligated to file any general consent to service of process or to qualify as a
foreign corporation or as a dealer in securities in any jurisdiction in which it
is not so qualified or to subject itself to taxation in respect of doing
business in any jurisdiction in which it is not otherwise so subject.

      (g) Rule 158. The Company will timely file such reports pursuant to the
Securities Exchange Act of 1934 (the "1934 Act") as are necessary in order to
make generally available to its securityholders as soon as practicable an
earnings statement for the purposes of, and to provide the benefits contemplated
by, the last paragraph of Section 11(a) of the 1933 Act.

      (h) Use of Proceeds. The Company will use the net proceeds received by it
from the sale of the Securities in the manner specified in the Prospectus under
"Use of Proceeds".

      (i) Listing. The Company will use its best efforts to effect the listing
of the Common Stock (including the Securities) on the Nasdaq National Market.

      (j) Restriction on Sale of Securities. During a period of 180 days from
the date of the Prospectus, the Company will not, without the prior written
consent of Merrill Lynch, (i) directly or indirectly, offer, pledge, sell,
contract to sell, sell any option or contract to purchase, purchase any option
or contract to sell, grant any option, right or warrant to purchase or otherwise
transfer or dispose of any share of Common Stock or any securities convertible
into or exercisable or exchangeable for Common Stock or file any registration
statement under the 1933 Act with respect to any of the foregoing or (ii) enter
into any swap or any other agreement or any transaction that transfers, in whole
or in part, directly or indirectly, the economic consequence of ownership of the
Common Stock, whether any such swap or transaction described in clause (i) or
(ii) above is to be settled by delivery of Common Stock or such other
securities, in cash or otherwise. The foregoing sentence shall not apply to (A)
the Securities to be sold hereunder, (B) any shares of Common Stock issued by
the Company upon the exercise of an option or warrant or the conversion of a
security outstanding on the date hereof and referred to in the Prospectus, (C)
any shares of Common Stock issued or options to purchase Common Stock granted
pursuant to existing employee benefit plans of the Company referred to in the
Prospectus, (D) any shares of Common Stock issued pursuant to any non-employee
director stock plan or dividend reinvestment plan or (E) shares of Common Stock,
up to an aggregate of 10% of the outstanding shares of Common Stock immediately
after the offering and sale of the Initial Securities, sold to partners,
vendors, manufacturers, distributors, customers, of other similar parties
pursuant to a strategic alliance or collaboration at a price greater than or
equal to the then market price of the Company's Common Stock, provided, however,
that in the case of subclause (E) above, the recipients of such Common Stock
agree to be bound by the restrictions of this Section 3(j).

      (k) Reporting Requirements. The Company, during the period when the
Prospectus is required to be delivered under the 1933 Act, will file all
documents required to be filed with the Commission pursuant to the 1934 Act
within the time periods required by the 1934 Act and the rules and regulations
of the Commission thereunder.

      (l) Compliance with NASD Rules. The Company hereby agrees that it will
ensure that the Reserved Securities will be restricted as required by the NASD
or the NASD rules from sale, transfer, assignment, pledge or hypothecation for a
period of 180 days following the date of this Agreement. The Underwriters will
notify the Company as to which persons will need to be so restricted. At the
request of

                                       12


the Underwriters, the Company will direct the transfer agent to place a stop
transfer restriction upon such securities for such period of time. Should the
Company release, or seek to release, from such restrictions any of the Reserved
Securities, the Company agrees to reimburse the Underwriters for any reasonable
expenses (including, without limitation, legal expenses) they incur in
connection with such release.

      SECTION 4. Payment of Expenses.

      (a) Expenses. The Company will pay or cause to be paid all expenses
incident to the performance of its obligations under this Agreement, including
(i) the preparation, printing and filing of the Registration Statement
(including financial statements and exhibits) as originally filed and of each
amendment thereto, (ii) the preparation, printing and delivery to the
Underwriters of this Agreement, any Agreement among Underwriters and such other
documents as may be required in connection with the offering, purchase, sale,
issuance or delivery of the Securities, (iii) the preparation, issuance and
delivery of the certificates for the Securities to the Underwriters, including
any stock or other transfer taxes and any stamp or other duties payable upon the
sale, issuance or delivery of the Securities to the Underwriters, (iv) the fees
and disbursements of the Company's counsel, accountants and other advisors, (v)
the qualification of the Securities under securities laws in accordance with the
provisions of Section 3(f) hereof, including filing fees and the reasonable fees
and disbursements of counsel for the Underwriters in connection therewith and in
connection with the preparation of the Blue Sky Survey and any supplement
thereto, (vi) the printing and delivery to the Underwriters of copies of each
preliminary prospectus and of the Prospectus and any amendments or supplements
thereto, (vii) the preparation, printing and delivery to the Underwriters of
copies of the Blue Sky Survey and any supplement thereto up to $20,000, (viii)
the fees and expenses of any transfer agent or registrar for the Securities,
(ix) the costs and expenses of the Company relating to investor presentations on
any "road show" undertaken in connection with the marketing of the Securities,
including without limitation, expenses associated with the production of road
show slides and graphics, fees and expenses of any consultants engaged in
connection with the road show presentations, travel and lodging expenses of the
representatives and officers of the Company and any such consultants, and the
cost of transportation chartered in connection with the road show, provided that
the cost of private aircraft chartered in connection with the road show shall be
limited to 50% of such private aircraft expenses, (x) the filing fees incident
to, and the reasonable fees and disbursements of counsel to the Underwriters in
connection with, the review by the NASD of the terms of the sale of the
Securities and (xi) the fees and expenses incurred in connection with the
inclusion of the Common Stock (including the Securities) for quotation on the
Nasdaq National Market and (xii) all costs and expenses of the Underwriters,
including the fees and disbursements of counsel for the Underwriters, in
connection with matters related to the Reserved Securities which are designated
by the Company for sale to Invitees. Except as otherwise provided herein, the
Underwriters shall be responsible for all other expenses incurred by the
Underwriters in performance of their obligations hereunder, including the fees
and expenses of their counsel.

      (b) Termination of Agreement. If this Agreement is terminated by the
Representatives in accordance with the provisions of Section 5, Section 9(a)(i)
or Section 11 hereof, the Company shall reimburse the Underwriters for all of
their out-of-pocket expenses, including the reasonable fees and disbursements of
counsel for the Underwriters.

      SECTION 5. Conditions of Underwriters' Obligations. The obligations of the
several Underwriters hereunder are subject to the accuracy of the
representations and warranties of the Company contained in Section 1 hereof or
in certificates of any officer of the Company delivered pursuant to the
provisions hereof, to the performance by the Company of its covenants and other
obligations hereunder, and to the following further conditions:

                                       13


      (a) Effectiveness of Registration Statement. The Registration Statement,
including any Rule 462(b) Registration Statement, has become effective and at
Closing Time no stop order suspending the effectiveness of the Registration
Statement shall have been issued under the 1933 Act or proceedings therefor
initiated or threatened by the Commission, and any request on the part of the
Commission for additional information shall have been complied with to the
reasonable satisfaction of counsel to the Underwriters. A prospectus containing
the Rule 430A Information shall have been filed with the Commission in
accordance with Rule 424(b) (or a post-effective amendment providing such
information shall have been filed and declared effective in accordance with the
requirements of Rule 430A).

      (b) Opinion of Counsel for Company. At Closing Time, the Representatives
shall have received the favorable opinion, dated as of Closing Time, of Wilson
Sonsini Goodrich & Rosati, P.C., counsel for the Company, in form and substance
satisfactory to counsel for the Underwriters, together with signed or reproduced
copies of such letter for each of the other Underwriters to the effect set forth
in Exhibit A hereto and to such further effect as counsel to the Underwriters
may reasonably request.

      (c) Opinions of Patent Counsel for Company.

            (i) At Closing Time, the Representatives shall have received the
      favorable opinion, dated as of Closing Time, of Sterne Kessler Goldstein
      Fox LLP, in form and substance satisfactory to counsel for the
      Underwriters, together with signed or reproduced copies of such letter for
      each of the other Underwriters to the effect set forth in Exhibit B-1
      hereto and to such further effect as counsel to the Underwriters may
      reasonably request.

            (ii) At Closing Time, the Representatives shall have received the
      favorable opinion, dated as of Closing Time, of the Quine Intellectual
      Property Law Group P.C., in form and substance satisfactory to counsel for
      the Underwriters, together with signed or reproduced copies of such letter
      for each of the other Underwriters to the effect set forth in Exhibit B-2
      hereto and to such further effect as counsel to the Underwriters may
      reasonably request.

      (d) Opinion of Counsel for Underwriters. At Closing Time, the
Representatives shall have received the favorable opinion, dated as of Closing
Time, of Latham & Watkins LLP, counsel for the Underwriters, together with
signed or reproduced copies of such letter for each of the other Underwriters
with respect to the matters set forth in clauses (i), (ii), (v) through (viii),
inclusive, (x) (solely as to the information in the Prospectus under
"Description of Capital Stock--Common Stock") and the penultimate paragraph of
Exhibit A hereto. In giving such opinion such counsel may rely, as to all
matters governed by the laws of jurisdictions other than the law of the State of
New York and the federal law of the United States and the General Corporation
Law of the State of Delaware, upon the opinions of counsel satisfactory to the
Representatives. Such counsel may also state that, insofar as such opinion
involves factual matters, they have relied, to the extent they deem proper, upon
certificates of officers of the Company and certificates of public officials.

      (e) Officers' Certificate. At Closing Time, there shall not have been,
since the date hereof or since the respective dates as of which information is
given in the Prospectus, any material adverse change in the condition, financial
or otherwise, or in the earnings, business affairs or business prospects of the
Company, whether or not arising in the ordinary course of business, and the
Representatives shall have received a certificate of the President or a Vice
President of the Company and of the chief financial or chief accounting officer
of the Company, dated as of Closing Time, to the effect that (i) there has been
no such material adverse change (ii) the representations and warranties in
Section 1(a) hereof are true and correct with the same force and effect as
though expressly made at and as of Closing Time (except those representations
and warranties that address matters only as of a particular date shall remain
true and correct as of such date), (iii) the Company has complied with all
agreements and satisfied all conditions

                                       14


on its part to be performed or satisfied at or prior to Closing Time, and (iv)
no stop order suspending the effectiveness of the Registration Statement has
been issued and no proceedings for that purpose have been instituted or are
pending or, to their knowledge, contemplated by the Commission.

      (f) Accountant's Comfort Letter. At the time of the execution of this
Agreement, the Representatives shall have received from Ernst & Young LLP a
letter dated such date, in form and substance satisfactory to the
Representatives, together with signed or reproduced copies of such letter for
each of the other Underwriters containing statements and information of the type
ordinarily included in accountants' "comfort letters" to underwriters with
respect to the financial statements and certain financial information contained
in the Registration Statement and the Prospectus.

      (g) Bring-down Comfort Letter. At Closing Time, the Representatives shall
have received from Ernst & Young LLP a letter, dated as of Closing Time, to the
effect that they reaffirm the statements made in the letter furnished pursuant
to subsection (f) of this Section, except that the specified date referred to
shall be a date not more than three business days prior to Closing Time.

      (h) Approval of Listing. At Closing Time, the Securities shall have been
approved for inclusion in the Nasdaq National Market, subject only to official
notice of issuance.

      (i) No Objection. The NASD has confirmed that it has not raised any
objection with respect to the fairness and reasonableness of the underwriting
terms and arrangements.

      (j) Lock-up Agreements. At the date of this Agreement, the Representatives
shall have received an agreement substantially in the form of Exhibit C hereto
signed by the persons listed on Schedule C hereto.

      (k) Conditions to Purchase of Option Securities. In the event that the
Underwriters exercise their option provided in Section 2(b) hereof to purchase
all or any portion of the Option Securities, the representations and warranties
of the Company contained herein and the statements in any certificates furnished
by the Company hereunder shall be true and correct as of each Date of Delivery
and, at the relevant Date of Delivery, the Representatives shall have received:

            (i) Officers' Certificate. A certificate, dated such Date of
      Delivery, of the President or a Vice President of the Company and of the
      chief financial or chief accounting officer of the Company confirming that
      the certificate delivered at the Closing Time pursuant to Section 5(e)
      hereof remains true and correct as of such Date of Delivery.

            (ii) Opinion of Counsel for Company. The favorable opinion of Wilson
      Sonsini Goodrich & Rosati, P.C., counsel for the Company, in form and
      substance satisfactory to counsel for the Underwriters, dated such Date of
      Delivery, relating to the Option Securities to be purchased on such Date
      of Delivery and otherwise to the same effect as the opinion required by
      Section 5(b) hereof.

            (iii) Opinion of Sterne Kessler Goldstein Fox LLP, Special Patent
      Counsel for Company. The favorable opinion of Sterne Kessler Goldstein Fox
      LLP, in form and substance satisfactory to counsel for the Underwriters,
      dated such Date of Delivery, relating to the Company's Intellectual
      Property and otherwise to the same effect as the opinion required by
      Section 5(c) (i) hereof.

            (iv) Opinion of Quine Intellectual Property Law Group P.C., Special
      Patent Counsel for Company. The favorable opinion of Quine Intellectual
      Property Law Group P.C., in form and

                                       15


      substance satisfactory to counsel for the Underwriters, dated such Date of
      Delivery, relating to the Company's Intellectual Property and otherwise to
      the same effect as the opinion required by Section 5(c) (ii) hereof.

            (v) Opinion of Counsel for Underwriters. The favorable opinion of
      Latham & Watkins LLP, counsel for the Underwriters, dated such Date of
      Delivery, relating to the Option Securities to be purchased on such Date
      of Delivery and otherwise to the same effect as the opinion required by
      Section 5(d) hereof.

            (vi) Bring-down Comfort Letter. A letter from Ernst & Young LLP, in
      form and substance satisfactory to the Representatives and dated such Date
      of Delivery, substantially in the same form and substance as the letter
      furnished to the Representatives pursuant to Section 5(f) hereof, except
      that the "specified date" in the letter furnished pursuant to this
      paragraph shall be a date not more than five days prior to such Date of
      Delivery.

      (l) Additional Documents. At Closing Time and at each Date of Delivery
counsel for the Underwriters shall have been furnished with such documents and
opinions as they may require for the purpose of enabling them to pass upon the
issuance and sale of the Securities as herein contemplated, or in order to
evidence the accuracy of any of the representations or warranties, or the
fulfillment of any of the conditions, herein contained; and all proceedings
taken by the Company in connection with the issuance and sale of the Securities
as herein contemplated shall be satisfactory in form and substance to the
Representatives and counsel for the Underwriters.

      (m) Termination of Agreement. If any condition specified in this Section
shall not have been fulfilled when and as required to be fulfilled, this
Agreement, or, in the case of any condition to the purchase of Option Securities
on a Date of Delivery which is after the Closing Time, the obligations of the
several Underwriters to purchase the relevant Option Securities, may be
terminated by the Representatives by notice to the Company at any time at or
prior to Closing Time or such Date of Delivery, as the case may be, and such
termination shall be without liability of any party to any other party except as
provided in Section 4 and except that Sections 1, 6, 7 and 8 shall survive any
such termination and remain in full force and effect.

      SECTION 6. Indemnification.

      (a) Indemnification of Underwriters. The Company agrees to indemnify and
hold harmless each Underwriter, its affiliates, as such term is defined in Rule
501(b) under the 1933 Act (each, an "Affiliate"), its selling agents and each
person, if any, who controls any Underwriter within the meaning of Section 15 of
the 1933 Act or Section 20 of the 1934 Act as follows:

            (i) against any and all loss, liability, claim, damage and expense
      whatsoever, as incurred, arising out of any untrue statement or alleged
      untrue statement of a material fact contained in the Registration
      Statement (or any amendment thereto), including the Rule 430A Information
      or the omission or alleged omission therefrom of a material fact required
      to be stated therein or necessary to make the statements therein not
      misleading or arising out of any untrue statement or alleged untrue
      statement of a material fact included in any preliminary prospectus or the
      Prospectus (or any amendment or supplement thereto), or the omission or
      alleged omission therefrom of a material fact necessary in order to make
      the statements therein, in the light of the circumstances under which they
      were made, not misleading;

            (ii) against any and all loss, liability, claim, damage and expense
      whatsoever, as incurred, to the extent of the aggregate amount paid in
      settlement of any litigation, or any

                                       16


      investigation or proceeding by any governmental agency or body, commenced
      or threatened, or of any claim whatsoever based upon any such untrue
      statement or omission, or any such alleged untrue statement or omission;
      provided that (subject to Section 6 (d) below) any such settlement is
      effected with the written consent of the Company;

            (iii) against any and all expense whatsoever, as incurred (including
      the fees and disbursements of counsel chosen by Merrill Lynch), reasonably
      incurred in investigating, preparing or defending against any litigation,
      or any investigation or proceeding by any governmental agency or body,
      commenced or threatened, or any claim whatsoever based upon any such
      untrue statement or omission, or any such alleged untrue statement or
      omission, to the extent that any such expense is not paid under (i) or
      (ii) above;

provided, however, that this indemnity agreement shall not apply to any loss,
liability, claim, damage or expense to the extent arising out of any untrue
statement or omission or alleged untrue statement or omission made in reliance
upon and in conformity with written information furnished to the Company by any
Underwriter through Merrill Lynch expressly for use in the Registration
Statement (or any amendment thereto), including the Rule 430A Information, or
any preliminary prospectus or the Prospectus (or any amendment or supplement
thereto); and, provided, further, that the Company will not be liable to any
Underwriter with respect to any Prospectus to the extent that the Company shall
sustain the burden of proving that any such loss, liability, claim, damage or
expense resulted from the fact that such Underwriter, in contravention of a
requirement of this Agreement or applicable law, sold Securities to a person to
whom such Underwriter failed to send or give, at or prior to the Closing Date, a
copy of the Final Prospectus, as then amended or supplemented if: (i) the
Company has previously furnished copies thereof (sufficiently in advance of the
Closing Date to allow for distribution by the Closing Date) to the Underwriter
and the loss, liability, claim, damage or expense of such Underwriter resulted
from an untrue statement or omission of a material fact contained in or omitted
from the Preliminary Prospectus which was correct in the Final Prospectus as, if
applicable, amended or supplemented prior to the Closing Date and such Final
Prospectus was required by law to be delivered at or prior to the written
confirmation of sale to such person and (ii) such failure to give or send such
Final Prospectus by the Closing Date to the party or parties asserting such
loss, liability, claim, damage or expense would have constituted the sole
defense to the claim asserted by such person.

      (b) Indemnification of Company, Directors and Officers. Each Underwriter
severally agrees to indemnify and hold harmless the Company, its directors, each
of its officers who signed the Registration Statement, and each person, if any,
who controls the Company within the meaning of Section 15 of the 1933 Act or
Section 20 of the 1934 Act, against any and all loss, liability, claim, damage
and expense described in the indemnity contained in subsection (a) of this
Section, as incurred, but only with respect to untrue statements or omissions,
or alleged untrue statements or omissions, made in the Registration Statement
(or any amendment thereto), including the Rule 430A Information or any
preliminary prospectus or the Prospectus (or any amendment or supplement
thereto) in reliance upon and in conformity with written information furnished
to the Company by such Underwriter through Merrill Lynch expressly for use in
the Registration Statement (or any amendment thereto) or such preliminary
prospectus or the Prospectus (or any amendment or supplement thereto).

      (c) Actions against Parties; Notification. Each indemnified party shall
give notice as promptly as reasonably practicable to each indemnifying party of
any action commenced against it in respect of which indemnity may be sought
hereunder, but failure to so notify an indemnifying party shall not relieve such
indemnifying party from any liability hereunder to the extent it is not
materially prejudiced as a result thereof and in any event shall not relieve it
from any liability which it may have otherwise than on account of this indemnity
agreement. In the case of parties indemnified pursuant to Section 6(a) above,
counsel to the indemnified parties shall be selected by Merrill Lynch, and, in
the case

                                       17


of parties indemnified pursuant to Section 6(b) above, counsel to the
indemnified parties shall be selected by the Company. An indemnifying party may
participate at its own expense in the defense of any such action; provided,
however, that counsel to the indemnifying party shall not (except with the
consent of the indemnified party) also be counsel to the indemnified party. In
no event shall the indemnifying parties be liable for fees and expenses of more
than one counsel (in addition to any local counsel) separate from their own
counsel for all indemnified parties in connection with any one action or
separate but similar or related actions in the same jurisdiction arising out of
the same general allegations or circumstances. No indemnifying party shall,
without the prior written consent of the indemnified parties, settle or
compromise or consent to the entry of any judgment with respect to any
litigation, or any investigation or proceeding by any governmental agency or
body, commenced or threatened, or any claim whatsoever in respect of which
indemnification or contribution could be sought under this Section 6 or Section
7 hereof (whether or not the indemnified parties are actual or potential parties
thereto), unless such settlement, compromise or consent (i) includes an
unconditional release of each indemnified party from all liability arising out
of such litigation, investigation, proceeding or claim and (ii) does not include
a statement as to or an admission of fault, culpability or a failure to act by
or on behalf of any indemnified party.

      (d) Settlement without Consent if Failure to Reimburse. If at any time an
indemnified party shall have requested an indemnifying party to reimburse the
indemnified party for fees and expenses of counsel, such indemnifying party
agrees that it shall be liable for any settlement of the nature contemplated by
Section 6(a)(ii) or settlement of any claim in connection with any violation
referred to in Section 6(e) effected without its written consent if (i) such
settlement is entered into more than 45 days after receipt by such indemnifying
party of the aforesaid request, (ii) such indemnifying party shall have received
notice of the terms of such settlement at least 30 days prior to such settlement
being entered into and (iii) such indemnifying party shall not have reimbursed
such indemnified party in accordance with such request prior to the date of such
settlement.

      (e) Indemnification for Reserved Securities. In connection with the offer
and sale of the Reserved Securities, the Company agrees to indemnify and hold
harmless the Underwriters, their Affiliates and selling agents and each person,
if any, who controls any Underwriter within the meaning of either Section 15 of
the 1933 Act or Section 20 of the 1934 Act, from and against any and all loss,
liability, claim, damage and expense (including, without limitation, any legal
or other expenses reasonably incurred in connection with defending,
investigating or settling any such action or claim), as incurred, (i) arising
out of the violation of any applicable laws or regulations of foreign
jurisdictions where Reserved Securities have been offered; (ii) arising out of
any untrue statement or alleged untrue statement of a material fact contained in
any prospectus wrapper or other material prepared by or with the consent of the
Company for distribution to Invitees in connection with the offering of the
Reserved Securities or caused by any omission or alleged omission to state
therein a material fact required to be stated therein or necessary to make the
statements therein not misleading; (iii) caused by the failure of any Invitee to
pay for and accept delivery of Reserved Securities which have been orally
confirmed for purchase by any Invitee by the end of the first business day after
the date of the Agreement; or (iv) related to, or arising out of or in
connection with, the offering of the Reserved Securities.

      SECTION 7. Contribution. If the indemnification provided for in Section 6
hereof is for any reason unavailable to or insufficient to hold harmless an
indemnified party in respect of any losses, liabilities, claims, damages or
expenses referred to therein, then each indemnifying party shall contribute to
the aggregate amount of such losses, liabilities, claims, damages and expenses
incurred by such indemnified party, as incurred, (i) in such proportion as is
appropriate to reflect the relative benefits received by the Company on the one
hand and the Underwriters on the other hand from the offering of the Securities
pursuant to this Agreement or (ii) if the allocation provided by clause (i) is
not permitted by applicable law, in such proportion as is appropriate to reflect
not only the relative benefits referred to in clause (i) above but also the
relative fault of the Company on the one hand and of the Underwriters on the

                                       18


other hand in connection with the statements or omissions, or in connection with
any violation of the nature referred to in Section 6(e) hereof, which resulted
in such losses, liabilities, claims, damages or expenses, as well as any other
relevant equitable considerations.

      The relative benefits received by the Company on the one hand and the
Underwriters on the other hand in connection with the offering of the Securities
pursuant to this Agreement shall be deemed to be in the same respective
proportions as the total net proceeds from the offering of the Securities
pursuant to this Agreement (before deducting expenses) received by the Company
and the total underwriting discount received by the Underwriters, in each case
as set forth on the cover of the Prospectus bear to the aggregate initial public
offering price of the Securities as set forth on the cover of the Prospectus.

      The relative fault of the Company on the one hand and the Underwriters on
the other hand shall be determined by reference to, among other things, whether
any such untrue or alleged untrue statement of a material fact or omission or
alleged omission to state a material fact relates to information supplied by the
Company or by the Underwriters and the parties' relative intent, knowledge,
access to information and opportunity to correct or prevent such statement or
omission or any violation of the nature referred to in Section 6(e).

      The Company and the Underwriters agree that it would not be just and
equitable if contribution pursuant to this Section 7 were determined by pro rata
allocation (even if the Underwriters were treated as one entity for such
purpose) or by any other method of allocation which does not take account of the
equitable considerations referred to above in this Section 7. The aggregate
amount of losses, liabilities, claims, damages and expenses incurred by an
indemnified party and referred to above in this Section 7 shall be deemed to
include any legal or other expenses reasonably incurred by such indemnified
party in investigating, preparing or defending against any litigation, or any
investigation or proceeding by any governmental agency or body, commenced or
threatened, or any claim whatsoever based upon any such untrue or alleged untrue
statement or omission or alleged omission.

      Notwithstanding the provisions of this Section 7, no Underwriter shall be
required to contribute any amount in excess of the amount by which the total
price at which the Securities underwritten by it and distributed to the public
were offered to the public exceeds the amount of any damages which such
Underwriter has otherwise been required to pay by reason of any such untrue or
alleged untrue statement or omission or alleged omission.

      No person guilty of fraudulent misrepresentation (within the meaning of
Section 11(f) of the 1933 Act) shall be entitled to contribution from any person
who was not guilty of such fraudulent misrepresentation.

      For purposes of this Section 7, each person, if any, who controls an
Underwriter within the meaning of Section 15 of the 1933 Act or Section 20 of
the 1934 Act and each Underwriter's Affiliates and selling agents shall have the
same rights to contribution as such Underwriter, and each director of the
Company, each officer of the Company who signed the Registration Statement, and
each person, if any, who controls the Company within the meaning of Section 15
of the 1933 Act or Section 20 of the 1934 Act shall have the same rights to
contribution as the Company. The Underwriters' respective obligations to
contribute pursuant to this Section 7 are several in proportion to the number of
Initial Securities set forth opposite their respective names in Schedule A
hereto and not joint.

      SECTION 8. Representations, Warranties and Agreements to Survive. All
representations, warranties and agreements contained in this Agreement or in
certificates of officers of the Company submitted pursuant hereto, shall remain
operative and in full force and effect regardless of (i) any investigation made
by or on behalf of any Underwriter or its Affiliates or selling agents, any
person

                                       19


controlling any Underwriter, its officers or directors, any person controlling
the Company and (ii) delivery of and payment for the Securities.

      SECTION 9. Termination of Agreement.

      (a) Termination; General. The Representatives may terminate this
Agreement, by notice to the Company, at any time at or prior to Closing Time (i)
if there has been, since the time of execution of this Agreement or since the
respective dates as of which information is given in the Prospectus, any
material adverse change in the condition, financial or otherwise, or in the
earnings, business affairs or business prospects of the Company considered as
one enterprise, whether or not arising in the ordinary course of business or
(ii) if there has occurred any material adverse change in the financial markets
in the United States or the international financial markets, any outbreak of
hostilities or escalation thereof or other calamity or crisis or any change or
development involving a prospective change in national or international
political, financial or economic conditions, in each case the effect of which is
such as to make it, in the judgment of the Representatives, impracticable or
inadvisable to market the Securities or to enforce contracts for the sale of the
Securities, or (iii) if trading in any securities of the Company has been
suspended or materially limited by the Commission or the Nasdaq National Market,
or if trading generally on the American Stock Exchange or the New York Stock
Exchange or in the Nasdaq National Market has been suspended or materially
limited, or minimum or maximum prices for trading have been fixed, or maximum
ranges for prices have been required, by any of said exchanges or by such system
or by order of the Commission, the NASD or any other governmental authority, or
(iv) a material disruption has occurred in commercial banking or securities
settlement or clearance services in the United States, or (v) if a banking
moratorium has been declared by either Federal or New York authorities.

      (b) Liabilities. If this Agreement is terminated pursuant to this Section,
such termination shall be without liability of any party to any other party
except as provided in Section 4 hereof, and provided further that Sections 1, 6,
7 and 8 shall survive such termination and remain in full force and effect.

      SECTION 10. Default by One or More of the Underwriters. If one or more of
the Underwriters shall fail at Closing Time or a Date of Delivery to purchase
the Securities which it or they are obligated to purchase under this Agreement
(the "Defaulted Securities"), the Representatives shall have the right, within
24 hours thereafter, to make arrangements for one or more of the non-defaulting
Underwriters, or any other underwriters, to purchase all, but not less than all,
of the Defaulted Securities in such amounts as may be agreed upon and upon the
terms herein set forth; if, however, the Representatives shall not have
completed such arrangements within such 24-hour period, then:

            (i) if the number of Defaulted Securities does not exceed 10% of the
      number of Securities to be purchased on such date, each of the
      non-defaulting Underwriters shall be obligated, severally and not jointly,
      to purchase the full amount thereof in the proportions that their
      respective underwriting obligations hereunder bear to the underwriting
      obligations of all non-defaulting Underwriters, or

            (ii) if the number of Defaulted Securities exceeds 10% of the number
      of Securities to be purchased on such date, this Agreement or, with
      respect to any Date of Delivery which occurs after the Closing Time, the
      obligation of the Underwriters to purchase and of the Company to sell the
      Option Securities to be purchased and sold on such Date of Delivery shall
      terminate without liability on the part of any non-defaulting Underwriter.

      No action taken pursuant to this Section shall relieve any defaulting
Underwriter from liability in respect of its default.

                                       20


      In the event of any such default which does not result in a termination of
this Agreement or, in the case of a Date of Delivery which is after the Closing
Time, which does not result in a termination of the obligation of the
Underwriters to purchase and the Company to sell the relevant Option Securities,
as the case may be, either the (i) Representatives or (ii) the Company shall
have the right to postpone Closing Time or the relevant Date of Delivery, as the
case may be, for a period not exceeding seven days in order to effect any
required changes in the Registration Statement or Prospectus or in any other
documents or arrangements. As used herein, the term "Underwriter" includes any
person substituted for an Underwriter under this Section 10.

      SECTION 11. Default by the Company. If the Company shall fail at Closing
Time or at the Date of Delivery to sell the number of Securities that it is
obligated to sell hereunder, then this Agreement shall terminate without any
liability on the part of any nondefaulting party; provided, however, that the
provisions of Sections 1, 4, 6, 7 and 8 shall remain in full force and effect.
No action taken pursuant to this Section shall relieve the Company from
liability, if any, in respect of such default.

      SECTION 12. Tax Disclosure. Notwithstanding any other provision of this
Agreement, from the commencement of discussions with respect to the transactions
contemplated hereby, the Company (and each employee, representative or other
agent of the Company) may disclose to any and all persons, without limitation of
any kind, the tax treatment and tax structure (as such terms are used in
Sections 6011, 6111 and 6112 of the U.S. Code and the Treasury Regulations
promulgated thereunder) of the transactions contemplated by this Agreement and
all materials of any kind (including opinions or other tax analyses) that are
provided relating to such tax treatment and tax structure.

      SECTION 13. Notices. All notices and other communications hereunder shall
be in writing and shall be deemed to have been duly given if mailed or
transmitted by any standard form of telecommunication. Notices to the
Underwriters shall be directed to the Representatives at 4 World Financial
Center, New York, New York 10080, attention of [_________]; notices to the
Company shall be directed to it at 2625 Hanover Street, Palo Alto, California
94304, attention of Calvin Y. H. Chow with a copy to Wilson Sonsini Goodrich &
Rosati, Professional Corporation, 650 Page Mill Road, Palo Alto, California
94304-1050, Attention: Michael J. O'Donnell.

      SECTION 14. Parties. This Agreement shall each inure to the benefit of and
be binding upon the Underwriters, the Company and their respective successors.
Nothing expressed or mentioned in this Agreement is intended or shall be
construed to give any person, firm or corporation, other than the Underwriters,
the Company and their respective successors and the controlling persons and
officers and directors referred to in Sections 6 and 7 and their heirs and legal
representatives, any legal or equitable right, remedy or claim under or in
respect of this Agreement or any provision herein contained. This Agreement and
all conditions and provisions hereof are intended to be for the sole and
exclusive benefit of the Underwriters, the Company and their respective
successors, and said controlling persons and officers and directors and their
heirs and legal representatives, and for the benefit of no other person, firm or
corporation. No purchaser of Securities from any Underwriter shall be deemed to
be a successor by reason merely of such purchase.

      SECTION 15. GOVERNING LAW. THIS AGREEMENT SHALL BE GOVERNED BY AND
CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

      SECTION 16. TIME. TIME SHALL BE OF THE ESSENCE OF THIS AGREEMENT. EXCEPT
AS OTHERWISE SET FORTH HEREIN, SPECIFIED TIMES OF DAY REFER TO NEW YORK CITY
TIME.

                                       21


      SECTION 17. Counterparts. This Agreement may be executed in any number of
counterparts, each of which shall be deemed to be an original, but all such
counterparts shall together constitute one and the same Agreement.

      SECTION 18. Effect of Headings. The Section headings herein are for
convenience only and shall not affect the construction hereof.

                                       22


      If the foregoing is in accordance with your understanding of our
agreement, please sign and return to the Company a counterpart hereof, whereupon
this instrument, along with all counterparts, will become a binding agreement
among the Underwriters and the Company in accordance with its terms.

                                        Very truly yours,

                                        NANOSYS, INC.

                                        By_____________________________
                                          Name:
                                          Title:

CONFIRMED AND ACCEPTED,
      as of the date first above written:

MERRILL LYNCH & CO.
MERRILL LYNCH, PIERCE, FENNER & SMITH
            INCORPORATED
LEHMAN BROTHERS INC.
CIBC WORLD MARKETS CORP.
NEEDHAM & COMPANY, INC.

By: Merrill Lynch, Pierce, Fenner & Smith Incorporated

By______________________________________________________
                  Authorized Signatory

For themselves and as Representatives of the other Underwriters named in
Schedule A hereto.

                                       23