UNIT PURCHASE AGREEMENT

     UNIT  PURCHASE  AGREEMENT  made  as  of  April  27,  2001  by  and  between
THERMOGENESIS  CORP.,  a Delaware  corporation  ("Seller")  and the  undersigned
investor ("Buyer").

     WHEREAS,  Seller is offering  (the  "Offering")  up to 78 units,  each unit
consisting of Fifty  Thousand  (50,000)  shares of the  Company's  Common Stock,
$0.001 par value and a warrant  representing  the right to acquire an additional
Ten Thousand (10,000) shares of the Company's Common Stock, $0.001 par value, at
an exercise price of $2.88 per share (each a "Unit"),  at a purchase price equal
to $90,000  (the  "Purchase  Price") per Unit,  to Buyer and other  investors in
accordance with the terms and subject to the conditions of this Agreement;

     WHEREAS,  subject to the terms and conditions set forth in this  Agreement,
Buyer  desires to subscribe for and  purchase,  and Seller  desires to issue and
sell to Buyer a certain number of Units;

     NOW,  THEREFORE,  in  consideration  of the  premises  and  of  the  mutual
covenants,  agreements and conditions  hereinafter set forth, the parties hereto
hereby agree as follows:

SECTION 1  PURCHASE AND SALE OF SECURITIES.

     1.1 Purchase and Sale of Securities.  In reliance upon the  representations
and warranties made herein and subject to the terms and conditions hereof, Buyer
intending to be legally  bound hereby  agrees to purchase from Seller and Seller
agrees to issue and sell to Buyer on the  Closing  Date the  number of Units set
forth  beneath  Buyer's name on the signature  page,  at the Purchase  Price per
Unit.

     Seller  proposes  to enter into this same form of purchase  agreement  with
certain other  investors  (the "Other  Buyers") and expects to complete sales of
the Units to them.  The Buyer and the Other  Buyers  are  hereinafter  sometimes
referred to as the "Buyers." and this Agreement and the  agreements  executed by
the Other Buyers are hereinafter  sometimes referred to as the "Agreements." The
Units,  including the shares of Common Stock issued as part of each Unit and the
shares of Common Stock issuable upon exercise of warrants issued as part of each
Unit, are hereinafter sometimes referred to as the "Securities."

     1.2 Purchase Price and Payment for the Securities. Simultaneously
with the execution and delivery of this Agreement, the Buyer is delivering to
THERMOGENESIS CORP. payment in an amount equal to the number of Units purchased
hereunder times the Purchase Price (the "Aggregate Purchase Price"). Payment of
the Aggregate  Purchase Price to the Company hereunder is being made by delivery
of a certified or bank cashier's check drawn payable to the order of the Company





or by wire transfer of the Aggregate  Purchase  Price to the Company or by other
means satisfactory to the Company.  Buyer understands and agrees that Seller, in
its sole discretion, reserves the right to accept or reject any subscription for
the  purchase of the Units,  in whole or in part,  and to withdraw  its offer to
sell the  Units at any time  prior to its  acceptance  of such  subscription  to
purchase.  A  subscription  shall be deemed  accepted  by the Seller when Seller
executes and delivers to the undersigned a counterpart of this Agreement.

     1.3 Time and  Place  Closing.  The  Securities  will be sold in one or more
closings at such place,  date and time as may be fixed by the Company (each such
date referred to herein as the "Closing  Date").  The initial Closing Date shall
be at the offices of the  Company,  3146 Gold Camp  Drive,  Rancho  Cordova,  CA
95670, or at such other place,  date or time as may be fixed by mutual agreement
by Buyer and Seller; provided, however, that the final Closing shall be no later
than April 27, 2001,  unless extended by the Company to May 1, 2001. The initial
closing,  if any, shall be conditioned  upon the sale of at least 72 Units.  For
purposes of the  minimum,  cancellation  of debt  participating  in the offering
shall be counted towards the number of Units.

     1.4 Delivery of Shares of Common Stock on the Closing Date. On each Closing
date,  Seller  shall  deliver,   (i)  against  payment  therefor,   certificates
representing  the shares of Common  Stock and the warrant  comprising  the Units
purchased by Buyer, and (ii) all other documents required to be delivered on the
Closing Date pursuant to this Agreement.  The Shares and Warrants have been duly
authorized and issued to the Buyer and, on the Closing Date,  will conform as to
legal matters to the description thereof contained in the Memorandum. Except for
the holders of the Company's  Series A preferred  stock, the stockholders of the
Company or holders of the  Company's  other  securities  have no  preemptive  or
similar rights with respect to the Securities.  The certificates  evidencing the
Shares and  Warrant as  delivered  to the Buyer will be in due and proper  legal
form.

SECTION 2  REPRESENTATIONS AND WARRANTIES OF SELLER.

     Seller represents and warrants to Buyer as follows:

     2.1 Corporate Organization. Seller is a corporation duly organized, validly
existing and in good standing under the laws of the State of Delaware,  with all
requisite corporate power and authority to own, operate and lease its properties
and to carry on its business as it is now being  conducted,  and is qualified or
licensed  to do  business in good  standing  in each  jurisdiction  in which the
property owned, leased or operated by it or the nature of the business conducted
by it makes such qualification or licensing necessary,  except where its failure
so to qualify to be licensed would not have a material adverse effect on Seller.

     2.2  Capitalization.  The  authorized  capital stock of Seller  consists of
50,000,000 shares of Common Stock, and 2,000,000 shares of preferred stock, both
par value  $0.001.  The issued and  outstanding  shares of the Seller's  capital
stock is  accurately  reflected  in its annual  report on Form 10-K for the year
ended June 30,  2000,  as of that date.  The attached  Schedule  2.2  accurately
reflects the shares of the Seller's  capital  stock issued since that date,  the




shares of capital stock options,  warrants and convertible privileges which have
been  reacquired  by the  Company  since that date,  and the number of shares of
capital stock,  options,  warrants and  convertible  privileges  (broken down by
class)  outstanding as of the Closing Date.  Except as described in the attached
Schedule 2.2 and in Seller's  annual report on Form 10-K for the year ended June
30,  2000,  there are no  outstanding  contracts,  agreements,  calls,  options,
warrants,  rights,  subscriptions,  obligations or other  commitments of Seller,
directly or indirectly, relating to or calling for the authorization,  issuance,
transfer,  sale or other  disposition of any share of the capital stock or other
voting   interests  of  Seller  or  securities   convertible,   exercisable   or
exchangeable  into or for any of the  foregoing.  Seller does not own or control
any stock,  equity,  voting  ownership  or other  interest  in any  corporation,
partnership, joint venture or other business association or entity.

     2.3 Authorization:  Validity. Seller has full corporate power and authority
to enter into the Agreements and to carry out its obligations  thereunder.  When
issued in  accordance  with the  Agreements,  the shares of Common Stock will be
validly issued, fully paid and nonassessable.  The execution and delivery of the
Agreements and the  consummation of the transactions  contemplated  thereby have
been duly  authorized by the Board of Directors of Seller,  which  authorization
remains in full force and  effect  and has not been  modified  or amended by any
subsequent action of such Board of Directors,  and no other corporate actions or
proceedings  on the part of Seller are necessary to authorize the  Agreements or
the transactions  contemplated  thereby. The Agreements constitute the valid and
binding obligations of Seller enforceable in accordance with their terms.

     2.4 No Violation.  Except for any required filings under applicable Federal
and state  securities  laws,  which Seller  undertakes to make,  the  execution,
delivery and performance by Seller of the Agreements and the  consummation by it
of the transactions  contemplated thereby,  including,  without limitation,  the
issuance,  sale and delivery of the shares of Common  Stock,  do not require the
consent, waiver,  approval,  license or authorization of or filing of any notice
or report  with any person,  entity or public  authority  and will not  violate,
result in a breach of or the acceleration of any obligation under, or constitute
a default  under,  any provision of Seller's  Certificate  of  Incorporation  or
By-laws  or  any  indenture,   mortgage,   lien,  lease,  agreement,   contract,
instrument,  order, judgment,  decree, law, ordinance or regulation to which any
property  of  Seller  is  subject  or by which  Seller is bound or result in the
creation  or  imposition  of any lien,  claim,  charge,  restriction,  equity or
encumbrance  of any  kind  whatsoever  upon,  or give to any  other  person  any
interest  or  right  in or  with  respect  to,  any of the  properties,  assets,
business, agreements or contracts of Seller.

     2.5  Compliance  With  Law.  To the  best of its  knowledge,  Seller  is in
compliance  with  the  governmental  laws,  ordinances,  codes,  orders,  rules,
regulations  and  requirements  applicable  to its  business and  conditions  of
employment,  except where noncompliance could not reasonably be expected to have
a material  adverse  effect on the  business,  assets,  properties  or financial
condition  of Seller.  Seller has obtained  all  permits,  licenses,  variances,
exemptions,  orders,  contracts and approvals  from  Federal,  state,  local and
foreign governmental and regulatory bodies which are material,  singularly or in
the aggregate, to the operation of its business (collectively, the "Permits" and
each individually,  a "Permit"). Seller is in compliance with the material terms
of each  Permit  and with all  requirements,  standards  and  procedures  of the




federal, state, local and foreign governmental or regulatory bodies which issued
the Permits or any of them and there does not exist under any of the Permits any
default or event of default or event  which with notice or lapse of time or both
would constitute an event of default by Seller.

     2.6 Memorandum and SEC Filings.  Seller previously has delivered to Buyer a
copy of its Private Placement Memorandum dated April 9, 2001 (the "Memorandum").
The  Memorandum  contains  information  concerning  the  Offering  and a copy of
Seller's Annual Report on Form 10-K for its fiscal year ended June 30, 2000, and
Quarterly  Reports on Form 10-Q for the quarterly  periods  ended  September 30,
2000  and  December  31,  2000  (the  "SEC  Report")  filed by  Seller  with the
Securities and Exchange  Commission (the "SEC").  Since January 1, 1997,  Seller
has made all filings required to be made by it under the Securities Act of 1933,
as amended  (the "1933  Act"),  the  Securities  Exchange Act of 1934 (the "1934
Act") and the  securities  laws of any  state,  and any  rules  and  regulations
promulgated  thereunder.   The  audited  and  unaudited  consolidated  financial
statements  of  Seller  included  in the  SEC  Reports  have  been  prepared  in
accordance with generally accepted accounting  principles  consistently  applied
(except  as may be  indicated  in the notes  thereto)  and  fairly  present  the
financial  position  of Seller as at the dates  thereof  and the  results of its
operations and changes in cash flows for the periods then ended. The information
contained in the  Memorandum and the SEC Reports is or was accurate and complete
as of the date given. No stop order preventing the use of the Memorandum, or any
other  amendment or supplement  thereto,  or any order asserting that any of the
transactions  contemplated  by this  Agreement  are subject to the  registration
requirements  of the Act, has been issued by the SEC.  The SEC  Reports,  at the
time they were or are hereafter filed or last amended,  as the case may be, with
the  Commission,  complied  and will comply in all  material  respects  with the
requirements of the Exchange Act of 1934. Neither the Agreements, the Memorandum
nor the SEC Reports,  taken as a whole, contain any untrue statement of material
fact or omit to state a material  fact  necessary  to make the  statements  made
therein,  in  light  of the  circumstances  under  which  they  were  made,  not
misleading.

     2.7 As of the Closing  Date  Intellectual  Property.  As  described  in the
Company's Form 10-K for the fiscal year 2000, the Company owns or possesses,  or
can  acquire  on  reasonable  terms,  all  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 and trade names ("Intellectual Property")
currently  employed  or  utilized  by it in  connection  with the  business  now
operated  and  proposed  to be  operated  by it and the  following  products  or
proposed products of the Company: The CryoSeal System and the BioArchive System.
The Company has not  received  any notice of  infringement  of or conflict  with
asserted  rights  of others  with  respect  to any  Intellectual  Property.  The
description  of the  Intellectual  Property in the  Company's  Form 10-K for the
fiscal  year 2000 does not contain any untrue  statement  of a material  fact or
omit to state any material  fact  required to be stated  therein or necessary to
make the statements  therein, in the light of the circumstances under which they
were made, not misleading.

     2.8 NASDAQ Compliance. Seller has taken all necessary actions to ensure its
continued  inclusion in, and the continued  eligibility  of the Common Stock for
trading on, The Nasdaq Stock Market ("NASDAQ") under all currently effective and




currently proposed inclusion requirements.

     2.9 Absence of Certain  Changes or Events.  Except as  disclosed in the SEC
Reports and on Schedule 2.2 hereto, since June 30, 2000, Seller has not:


     (a)  incurred any  obligation  or  liability,  whether  fixed or contingent
          (including,  without  limitation,  any  liability  as a  guarantor  or
          otherwise  with respect to the  liabilities  of others),  except those
          incurred  in the  ordinary  course  of  business,  none  of  which  is
          materially  adverse,  and except in connection with the Agreements and
          the transactions contemplated thereby;

     (b)  discharged or satisfied any lien or encumbrance or paid any obligation
          or liability (fixed or contingent),  other than in the ordinary course
          of business;

     (c)  mortgaged,  pledged or subjected to lien, charge, security interest or
          to any other  encumbrance any of its assets or properties,  other than
          in the ordinary course of business;

     (d)  transferred,  leased or  otherwise  disposed  of any of its  assets or
          properties  except for a fair  consideration in the ordinary course of
          business  or  acquired  any  assets or  properties,  other than in the
          ordinary course of business;

     (e)  canceled or compromised any debt or claim,  other than in the ordinary
          course of business;

     (f)  waived or  released  any rights of material  value,  other than in the
          ordinary course of business;

     (g)  suffered  any  casualty  loss or damage  (whether  or not such loss or
          damage  shall have been covered by  insurance)  which  materially  and
          adversely  affects the ability of Seller to conduct its business as it
          is presently conducted;

     (h)  declared any dividend or made any payment or  distribution  in respect
          of its Common Stock;

     (i)  been the subject of any  regulatory  action,  citation  or  comparable
          action or entered into any consent order with government agencies with
          regard to its operations or products;

     (j)  implemented any material change in accounting principles, practices or
          methods; or

     (k)  experienced a material  adverse  change in its financial  condition or
          results of operation.



     2.10 Private Offering.  Subject to the accuracy of the  representations  of
Buyer in Section 3 hereof and the similar representations of the Other Buyers in
the Agreements,  the offer, sale and issuance of the Units,  which are comprised
of shares of  Common  Stock and  Warrant  to  purchase  shares of Common  Stock,
constitute  transactions exempt from the registration  requirements of Section 5
of the 1933 Act and neither Seller nor anyone acting on its behalf will take any
action hereafter that would cause the loss of such exemption.

SECTION 3.  REPRESENTATIONS AND WARRANTIES OF BUYER.

     Buyer  understands  that the  issuance  and sale of the  Units,  which  are
comprised  of shares of Common  Stock and Warrant to  purchase  shares of Common
Stock,  have not been  registered  under the 1933 Act, on the  grounds  that the
issuance and sale of such  securities to the Buyer is exempt pursuant to Section
4(2) of the 1933 Act and/or  Regulation  D  promulgated  under the 1933 Act, and
that the  reliance of Seller on such  exemptions  is  predicated  in part on the
Buyer's representations,  warranties, covenants and acknowledgments set forth in
this Section 3.

     3.1 Authorization. If Buyer is a corporation, it represents and warrants to
Seller that it is a corporation  duly  organized,  validly  existing and in good
standing  under  the  laws of the  state of its  incorporation;  that it was not
organized for the specific purpose of purchasing the Units to be purchased by it
hereunder;  that it has full  corporate  power and  authority to enter into this
Agreement and to carry out its obligations  hereunder;  all corporate actions or
proceedings  on the  part of such  Buyer  as are  necessary  to  authorize  this
Agreement or the  transactions  contemplated  hereby;  and that the transactions
contemplated hereby have been taken. Buyer represents and warrants to the Seller
that this Agreement  constitutes the valid and binding obligation of such Buyer,
enforceable in accordance  with its  respective  terms except to the extent that
enforceability may be limited by equity,  bankruptcy,  insolvency and other laws
of general application affecting the rights and remedies of creditors.

     3.2 Purchase  Without View to Distribute.  Buyer represents and warrants to
Seller that the Units, which are comprised of shares of Common Stock and Warrant
to purchase shares of Common Stock, being purchased by it are being acquired for
its own  account,  not as a nominee  or agent,  and not with a view to resale or
distribution  within the  meaning of the 1933 Act and the rules and  regulations
thereunder.

     3.3 Restrictions on Transfer.

     (a) Buyer (i) acknowledges that the Securities are not registered under the
1933 Act and that the Securities must be held indefinitely by it unless they are
subsequently  registered under the 1933 Act or an exemption from registration is
available, (ii) is aware that any routine sales of the Securities under Rule 144
of the SEC  under  the  1933  Act may be made  only in  limited  amounts  and in
accordance  with the terms and  conditions  of that Rule and that in such  cases
where  the Rule is not  applicable,  compliance  with  some  other  registration
exemption  will be  required,  (iii) is  aware  that  Rule 144 is not  presently




available for use by Buyer for resale of any such  Securities and that there can
be no assurance that Rule 144 will be available at any time in the future,  (iv)
is aware that,  except as provided in Section 5 hereof,  Seller is not obligated
to register  under the 1933 Act any sale,  transfer or other  disposition of the
Securities,  (v) is aware that Seller  shall not be  required  to  register  the
transfer of the  Securities on the books of Seller unless Seller shall have been
provided with an opinion of counsel satisfactory to it prior to such transfer to
the  effect  that  registration  under  the  1933  Act or any  applicable  state
securities  law has been  effected  or is not  required in  connection  with the
transaction  resulting in such transfer,  and (vi) is aware that the Securities,
and each certificate  representing the Securities and any shares of Common Stock
or other  securities  issued in respect of such Securities upon any stock split,
stock dividend, recapitalization,  merger, consolidation or similar event, shall
(unless otherwise  permitted by paragraph (b) of this Section 3.4) be stamped or
otherwise imprinted with the following legend:

     "THE  SECURITIES  REPRESENTED  BY  THIS  CERTIFICATE  MAY  NOT BE  SOLD  OR
     OTHERWISE DISPOSED OF IN THE ABSENCE OF AN EFFECTIVE REGISTRATION UNDER THE
     SECURITIES  ACT OF 1933,  AS  AMENDED  (THE  "ACT")  AND  APPLICABLE  STATE
     SECURITIES  LAWS,  OR AN OPINION OF COUNSEL THAT SUCH  REGISTRATION  IS NOT
     REQUIRED UNDER THE ACT AND THE RULES AND REGULATIONS PROMULGATED THEREUNDER
     OR UNDER APPLICABLE  STATE  SECURITIES LAWS AND THAT SUCH  REGISTRATION HAS
     BEEN EFFECTED."

     (b) The restrictions on the  transferability  of the Securities shall cease
and terminate when such Securities shall have been registered under the 1933 Act
and are  proposed  to be sold or  otherwise  disposed of in  accordance  with an
intended method of disposition by the Seller or Sellers thereof set forth in the
registration  statement covering such Securities  required by Section 5.2 or any
other   applicable   registration   statement,   or  when  such  Securities  are
transferable in accordance with the provisions of Rule 144(k)  promulgated under
the  1933  Act.  Whenever  the  restrictions  on  transfer  shall  terminate  as
hereinabove  provided with respect to any of the  Securities,  the holder of any
such  Securities  bearing the legend set forth in paragraph  (a) of this Section
3.3 as to which such  conditions  shall have  terminated  shall be  entitled  to
receive from Seller,  without  expense (except for the payment of any applicable
transfer  tax) and as  expeditiously  as possible,  new stock  certificates  not
bearing such legend.

     3.4  Access  to  Information.  Each  Buyer  acknowledges  that it has  been
provided  with a copy of the  Memorandum  (including  the SEC  Reports)  and has
carefully  reviewed the same.  Buyer further  acknowledges  that Seller has made
available to it the  opportunity  to ask  questions of and receive  answers from
Seller's  officers and  directors  concerning  the terms and  conditions  of the
Offering and the business and financial condition of the Seller, and to acquire,
and each Buyer has  received to its  satisfaction,  such  information  about the
business and financial  condition of Seller and the terms and  conditions of the
offering as it has requested.



     3.5 Additional Representations of Buyer. Buyer represents that (i) it is an
"accredited  investor" as such term is defined in Rule 501 promulgated under the
1933 Act,  (ii) its  financial  situation is such that it can afford to bear the
economic risk of holding the  Securities  for an  indefinite  period of time and
suffer complete loss of its investment in the Securities, (iii) it has the funds
necessary  to  purchase  the  Units  immediately  available  to it and  (iv) its
knowledge and  experience in financial and business  matters are such that it is
capable  of  evaluating  the merits  and risks of its  purchase  of the Units as
contemplated by this Agreement.

SECTION 4. COVENANTS OF SELLER.

     4.1 Consummation of Agreements. Seller shall perform and fulfill
all conditions and obligations on its part to be performed and fulfilled under
the Agreements, to the end that the transactions contemplated by the Agreements
shall be carried out. To this end, Seller will obtain all necessary
authorizations or approvals of its Board of Directors to the execution and
performance of the Agreements, which shall include as integral parts thereof the
issuance to Buyer of the Securities upon the terms and conditions set forth in
the Agreements.

     4.2 Compliance  with  Regulation D. Seller agrees to file a Form D with the
SEC within  fifteen  days of the date of the  Closing  and to file,  on a timely
basis,  any  amendments or  supplements  to such Form D as may be required under
Regulation D promulgated  under the 1933 Act.  Seller also agrees to comply with
the filing  requirements of state  securities laws applicable to the sale of the
Units hereunder.

     4.3 Good  Faith  Effort  to  Effect  Transfers.  Upon  registration  of the
Securities,  or  the  termination  under  the  provisions  of  Rule  144  of the
restriction  on transfer,  the Seller agrees to issue or cause its corporate and
securities  counsel  to issue all  required  consents  or  opinions  that may be
required to effect the transfer of the  Securities  and removal of any legend on
such  Securities  upon transfer.  Seller agrees that it shall use all reasonable
efforts to cause such consents or opinions of counsel to be  transmitted  to the
Seller's  transfer  agent  within 24 hours of  receipt  of a  request  by Buyer,
provided that all required certifications or representations  required to effect
such transfer have been provided with such request.  The Seller will pay its own
legal expenses to prepare such consents or opinions of counsel  contemplated  by
this Section 4.3.

SECTION 5. REGISTRATION.

     5.1 Definitions. As used herein:

     (a) The  terms  "register,"  "registered"  and  "registration"  refers to a
registration  effected  by  preparing  and filing a  registration  statement  in
compliance   with  the  1933  Act  and  the   declaration  or  ordering  of  the
effectiveness of such registration statement.

     (b) For the purposes hereof, the term "Registrable  Securities" means, with
respect  to the Units  offered  hereby,  the  shares of Common  Stock  purchased
hereunder,  the  shares  of  Common  Stock to be  issued  upon  exercise  of the




Warrants,  and any stock to be issued in respect of, or part of, the Registrable
Securities as a result of a stock split,  stock  dividend,  recapitalization  or
combination.

     (c) The terms  "Holder"  or  "Holders"  mean any  person or persons to whom
Registrable  Securities were originally  issued or qualifying  transferees under
Section 5.6 hereof who hold Registrable Securities.

     5.2 Filing of  Registration  Statement.  Within 45 days  after the  Closing
Date, the Seller will prepare and file a Registration Statement on Form S-3 (the
"Registration  Statement")  with the SEC in order  to  register  the sale of the
Registrable Securities by Buyers from time to time through underwriters,  agents
or  otherwise,  in  negotiated or market  transaction  or through  NASDAQ or the
facilities of any national securities exchange on which the Common Stock is then
traded or in privately negotiated transactions. Seller will use its best efforts
to obtain a declaration of effectiveness of such Registration Statement and take
all actions incidental thereto (including,  without limitation, the execution of
an undertaking to file  post-effective  amendments,  appropriate  qualifications
under the applicable  blue sky or other state  securities  laws and  appropriate
compliance  with exemptive  regulations  issued under the 1933 Act and any other
governmental  requirements  or  regulations)  as may be  necessary  to permit or
facilitate the public sale and distribution of the Registrable Securities by the
Holders.  Notwithstanding  the foregoing,  to the extent  available,  Buyers may
utilize Rule 144 for the resale of the Registrable Securities.

     5.3  Expenses.  All  expenses  incurred  currently  or  in  the  future  in
connection with any registration  pursuant to this Section 5, including  without
limitation,  all registration,  filing and  qualification  fees (including those
attributable  to  the  Registrable  Securities),  printing  expenses,  fees  and
disbursements  of counsel for Seller and fees and expenses of counsel for Seller
incurred pursuant to Section 4.3 of this Agreement or Section 4.3 of the Warrant
Certificate  and expenses of any comfort  letters or special  audits of Seller's
financial  statements  incidental to or required by such  registration  shall be
borne by  Seller  (excluding  underwriting  discounts  and  selling  commissions
payable with respect to the sale of Registrable Securities).

     5.4   Registration   Procedures.   In  the   case  of  each   registration,
qualification  or compliance  effected by the Seller pursuant to this Section 5,
Seller will, at its expense:

     (a) keep such registration statement effective and file any necessary post-
effective  amendments  and use its best  efforts to maintain  the  effectiveness
thereof  until the  earlier  of (i) such time as Seller  reasonably  determines,
based upon an opinion of counsel,  that the Holders will be eligible to sell all
of the Registrable  Securities then owned by the Holders without registration in
the open market in  compliance  with the 1933 Act and  without  regard to volume
restrictions or (ii) for a period of 36 months from the date of effectiveness of
the Registration Statement.

     (b) prepare and file with the SEC such  amendments and  supplements to such
Registration   Statement  as  may  be  necessary  to  keep  such   registration,
qualification or compliance effective and comply with the provisions of the 1933




Act with respect to the disposition of all securities covered thereby during the
applicable period;

     (c) update, correct, amend and supplement such registration,  qualification
or compliance as necessary;

     (d) furnish such number of  preliminary  and final  prospectuses  and other
documents incident thereto as a Holder from time to time may reasonably request;

     (e)  register or qualify  such  Registrable  Securities  for offer and sale
under the Blue Sky or securities  laws of such  jurisdictions  as any Holder may
reasonably  designate  to  enable  it  to  consummate  the  disposition  of  the
Registrable  Securities  in such  jurisdiction,  except that Seller shall not be
required  in  connection  therewith  or as a  condition  thereof to qualify as a
foreign corporation or to execute a general consent to service of process in any
State;

     (f) timely file all  reports  required to be filed by it under the 1933 Act
or the 1934 Act and the rules and regulations adopted by the SEC thereunder, all
to the  extent  required  to  enable  each  such  Buyer to sell the  Registrable
Securities  without  registration  under the 1933 Act  pursuant  to (i) Rule 144
adopted by the SEC under the 1933 Act, as such rule may be amended  from time to
time, or (ii) any similar rule or regulation hereafter adopted by the SEC;

     (g) take all action necessary to render the Registrable Securities eligible
for inclusion on NASDAQ for trading thereon; and

     (h)  upon  the  sale  of  any  Registrable   Securities  pursuant  to  such
Registration  Statement remove all restrictive  legends from all certificates or
other instruments evidencing the Registrable Securities.

     5.5 Further  Information.  If Registrable  Securities owned by a Holder are
included in the Registration Statement, such Holder shall furnish to Seller such
information  regarding  itself as Seller may reasonable  request and as shall be
required  in  connection  with any  registration,  qualification  or  compliance
referred to in this Section 5.

SECTION 6. INDEMNIFICATION.

     6.1 Indemnification of Buyer. Seller agrees to indemnify and hold harmless,
to the extent  permitted  by law,  Buyer,  its  directors  and officers and each
person who controls  Buyer  (within the meaning of the 1933 Act) against any and
all losses, claims,  damages,  liabilities and expenses caused by (i) any breach
of the representations, warranties, covenants and agreements of Seller contained
in the  Agreements;  or (ii) any untrue or alleged untrue  statement of material
fact  contained  in  any  registration  statement,   prospectus  or  preliminary
prospectus  filed  pursuant  to  Section 5 hereof  or 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,  except insofar as the




same are  caused by or  contained  in any  information  furnished  in writing to
Seller by Buyer expressly for use in such registration statement or prospectus.

     6.2 Indemnification of Seller. Buyer agrees to furnish to Seller in writing
such  information  and  affidavits  as  Seller  reasonably  requests  for use in
connection with any registration statement or prospectus and agrees to indemnify
and hold harmless,  to the extent  permitted by law,  Seller,  its directors and
officers  and each person who  controls  Seller  (within the meaning of the 1933
Act)  against any and all losses,  claims,  damages,  liabilities  and  expenses
caused by (i) any  breach of the  representations,  warranties,  covenants,  and
agreements of Buyer contained in this  Agreement;  or (ii) any untrue or alleged
untrue statement of material fact or any omission of a material fact required to
be stated in any registration  statement,  prospectus or preliminary  prospectus
filed pursuant to Section 5 hereof or necessary to make the  statements  therein
not  misleading,  but only to the  extent  that such  untrue or  alleged  untrue
statement or omission is contained or omitted in any information or affidavit so
furnished  in writing by such Buyer,  and in no event will Buyer be obligated to
indemnify Seller,  its directors,  officers or any person who controls Seller in
an amount in excess of the proceeds to be derived from the sale of Securities in
the offering giving rise to a claim for indemnification.

     6.3 Contribution.  If the indemnification provided for in this section 6 is
judicially  determined to be unavailable to an indemnified  person in respect of
any losses,  claims, damages or liabilities referred to herein, then, in lieu of
indemnifying such indemnified  person hereunder,  each party shall contribute to
the  amount  paid or  payable  by such  indemnified  person  as a result of such
losses,  claims,  damages or liabilities (and expense  relating  thereto) (i) in
such proportion as is appropriate to reflect the relative benefits to Seller, on
the one hand, and Buyer,  on the other hand, or (ii) if the allocation  provided
by clause (i) above is not  available,  in such  proportion as is appropriate to
reflect not only the relative  benefits  referred to in such clause (i) but also
the  relative  fault  of  each,  as  well  as  any  other   relevant   equitable
considerations.

     6.4 Defense of Action.  Any person  entitled to  indemnification  hereunder
will (i) give prompt notice to the indemnifying  party of any claim with respect
to which it seeks  indemnification;  and (ii) unless in such indemnified party's
reasonable  judgment  a  conflict  of  interest  between  such  indemnified  and
indemnifying   parties  may  exist  with  respect  to  such  claim,  permit  the
indemnifying  party to assume the defense of such claim with counsel  reasonably
satisfactory  to the  indemnified  party.  If such defense is not  assumed,  the
indemnifying  party will not be subject to any liability for any settlement made
without its consent  (but such consent will not be  unreasonably  withheld).  An
indemnifying  party who is not entitled to, or elects not to, assume the defense
of a claim will not be  obligated  to pay the fees and expenses of more than one
counsel for all parties  indemnified by such indemnifying  party with respect to
such  claim,  unless  in the  reasonable  judgment  of any  indemnified  party a
conflict of interest may exist between such  indemnified  party and any other of
such indemnified parties with respect to such claim.

     6.5 The remedies provided for in this Section 6 are not exclusive and shall



not  limit  any  rights or  remedies  that may  otherwise  be  available  to any
indemnified party at law or in equity.

SECTION 7.  CONDITIONS PRECEDENT TO BUYER'S OBLIGATIONS.

     7.1  Conditions.  The obligations of Buyer to consummate the Agreements and
the  transactions  contemplated  hereby are subject to the  satisfaction  of the
following  conditions  on or prior to the Closing Date except to the extent that
any such condition can be and is waived by Buyer:

     (a) Representations; Warranties; Covenants. Each of the representations and
warranties of Seller  contained in Section 2 hereof shall be true and correct in
all material  respects as though made at the time of and as of the Closing Date;
Seller  shall,  at or  before  the  Closing  Date,  have  performed  all  of its
obligations hereunder which by the terms hereof are to be performed on or before
the Closing Date,  and Seller shall have delivered to Buyer a Certificate of its
President  or Vice  President  dated  as of the  Closing  Date to the  foregoing
effect.

     (b) Opinion of Counsel. At each Closing, Seller's Counsel shall have issued
to Buyer an  opinion  of counsel  as to this  transaction's  compliance  with or
exemption from federal and applicable state securities laws and as to such other
matters as are customarily included in opinions relating to transactions of this
kind in form reasonably satisfactory to Buyer.

SECTION 8.  CONDITIONS PRECEDENT TO SELLER'S OBLIGATIONS.

     8.1 Conditions. The obligations of Seller to consummate the
Agreements and the transactions contemplated hereby are subject to the
satisfaction of the following conditions on or prior to the Closing Date except
to the extent that any such condition can be and is waived by Seller:

     (a) Representations; Warranties; Covenants. Each of the representations and
warranties  of Buyer  contained in Section 3 hereof shall be true and correct in
all material respects as though made at the time of and as of the Closing; Buyer
shall, at or before the Closing, have performed all of its obligations hereunder
which by the terms hereof are to be  performed on or before the Closing.  Unless
Seller  receives  written  notification  to the contrary at the Closing,  Seller
shall be entitled to assume the preceding is accurate at the Closing.

SECTION 9.  MISCELLANEOUS.

     9.1 Law Governing.  This Agreement shall be construed under and governed by
the laws of the State of California applicable to contracts made and to be fully
performed therein.

     9.2 Broker or  Finder.  Buyer  represents  and  warrants  that no broker or
finder  has acted  for such  party in  connection  with  this  Agreement  or the
transactions  contemplated  by this  Agreement  and that no  broker or finder is
entitled to any broker's or finder's fee or other  commission in respect thereof
based in any way on agreements, arrangements or understandings made by Buyer.


     9.3  Notices.  All  notices,  requests,  demands  or  other  communications
hereunder  shall be deemed to have been  duly  given if  delivered  or mailed by
certified  or  registered  mail if to Seller at 3146  Gold  Camp  Drive,  Rancho
Cordova, California 95670, Attn: Chief Executive Officer, and if to the Buyer at
the address set forth on the signature page hereto,  or to such other address of
which either party may notify the other party.

     9.4 Survival of Representations,  Warranties and Covenants. Notwithstanding
any  investigation  made by any party to this  Agreement,  all  representations,
warranties,  covenants  and  obligations  made by Seller and Buyer  herein shall
survive the execution of this  Agreement and the sale and delivery of the shares
of Common Stock and warrants to purchase shares of Common Stock.

     9.5 Entire Agreement. This Agreement,  including the exhibits and schedules
referred   to  herein,   is   complete   and  all   promises,   representations,
understandings,  warranties and agreements  with reference to the subject matter
hereof,  and all  inducements  to the making of this  Agreement  relied  upon by
either  party  hereto,  have  been  expressed  herein  or in such  exhibits  and
schedules.

     9.6  Assignment.  This  Agreement  may not be assigned  by either  Buyer or
Seller  without the prior  written  consent of the other party.  This  Agreement
shall be  enforceable  by and shall inure to the benefit of and be binding  upon
the parties hereto and their successors and no others.

     9.7 Fees and Expenses.  Except as otherwise  specifically  provided herein,
each  of the  parties  will  bear  its  own  expenses  in  connection  with  the
negotiation and consummation of the transactions contemplated by this Agreement.

     9.8  Publicity  and  Disclosure.  Except  as may  be  required  by  federal
securities laws, no press release or public disclosure,  either written or oral,
of the  transactions  contemplated  by this  Agreement,  shall  be made by Buyer
hereto without the prior approval of Seller.

     9.9 Counterparts. This Agreement may be executed simultaneously in multiple
counterparts,  each of  which  shall be  deemed  an  original,  but all of which
together shall constitute one and the same document.

     9.10  Amendments  and Waivers.  Except as otherwise  provided  herein,  any
provision in any of the Agreements may be amended or waived only if Seller shall
obtain the written consent of the holders of a majority in interest of the Units
purchased from Sellers pursuant to the Agreements.

                   [THIS SPACE WAS INTENTIONALLY LEFT BLANK.]





     IN WITNESS  WHEREOF,  the parties  hereto have caused this  Agreement to be
executed as of the date set forth above.

THERMOGENESIS CORP.



By:     ____________________________
        Philip H. Coelho,
        Chief Executive Officer







                                            -----------------------------------
                                            PRINT NAME OF BUYER


                                            -----------------------------------
                                            SIGNATURE OF BUYER

                                            -----------------------------------


                                            -----------------------------------
                                            [Principal Address of Buyer]

                                            -----------------------------------
                                            [Tax Identification Number]


                                            Number of Units
                                            to be Purchased:
                                                                 --------------

                                            Price per Unit:      $
                                                                 --------------
                                            Aggregate Purchase
                                            Price:               $
                                                                  -------------