<PAGE>

                                                                   EXHIBIT 10.27

                            STOCK PURCHASE AGREEMENT

         This Stock Purchase Agreement (the "Agreement") is entered into on
November 12, 2002 by and between Cell Robotics International, Inc., a Colorado
corporation ("Seller"), and Mr. Oton M. Tisch (the "Buyer"). Buyer and Seller
are referred to collectively herein as the "Parties."

                             PRELIMINARY STATEMENTS

1.       Seller desires to sell, issue and deliver to Buyer certain shares of
common stock, par value $.004 per share, of Seller (the "Common Stock"); and

2.       Buyer desires to purchase from Seller such shares of Common Stock on
the terms and subject to the conditions set forth herein.

                                    AGREEMENT

         The Parties, intending to be legally bound, agree as follows:

1.       PURCHASE, SALE AND DELIVERY

         1.1      The Shares. Subject to the terms and conditions of this
Agreement, at the Closing (as defined below), Seller shall sell, issue and
deliver to Buyer and Buyer shall acquire and purchase from Seller, all right,
title and interest into 3,086,204 shares of Common Stock ("Shares").

         1.2      Purchase Price. The Parties agree that the total purchase
price for issuing the Shares shall be an amount equal to $1,388,792 (the
"Purchase Price"), which shall be comprised of the following: (a) the repayment
in full of $900,000 of principal and $139,165 of accrued but unpaid interest
owing by Seller to Buyer under that certain Loan Agreement dated January 31,
2001 between Buyer and Seller (as amended, the "Loan Agreement"), and (b) the
repayment in full of $337,300 of principal and $12,327 of accrued but unpaid
interest owing by Seller to Buyer under that certain Amended and Restated
Promissory Note in the face amount of $2,000,000 dated effective September 17,
2002 executed by Seller and payable to the order of Buyer (the "Note"). Upon
issuance of the Shares, Buyer acknowledges and agrees that (i) all principal,
interest and other obligations owing by Seller to Buyer under the Loan Agreement
shall be deemed to be repaid, satisfied and forever discharged and all
obligations of Seller to Buyer under the Loan Agreement shall be deemed
terminated and of no further force and effect and (ii) all principal and
interest described in clause (b) of this Section 1.2 outstanding under the Note
shall be deemed to be repaid, satisfied and forever discharged.


                                       1
<PAGE>

         1.3      Closing. The closing of the transactions contemplated by this
Agreement (the "Closing") shall take place at the offices of Seller, 2715
Broadbent Parkway N.E., Albuquerque, New Mexico, on November 12, 2002 or such
other date as Buyer and Seller may mutually determine (the "Closing Date").

         1.4      Deliveries at the Closing. At the Closing, (a) Seller will
deliver to Buyer one or more stock certificates representing the Shares, and (b)
Seller will deliver a warrant (the "Warrant") substantially in the form as
Exhibit A attached hereto to purchase that number of shares of Common Stock
equal to 771,551 shares of Common Stock.

2.       REPRESENTATIONS AND WARRANTIES OF SELLER

         Seller represents and warrants to Buyer the following:

         2.1      Corporate Status and Good Standing. Seller is a corporation
duly organized, validly existing, and in good standing under the laws of
Colorado.

         2.2      Authorization of Transaction. Seller has full power and
authority to execute and deliver this Agreement and the Warrant and to perform
its obligations hereunder and thereunder. The execution and delivery of this
Agreement by Seller and the Warrant and the consummation by Seller of the
transactions contemplated hereby have been duly and validly authorized by all
necessary corporate action. Each of this Agreement and the Warrant constitutes
the valid and legally binding obligation of Seller, enforceable in accordance
with its terms and conditions, except as enforceability may be limited by
general equitable principles, bankruptcy, insolvency, reorganization, moratorium
or other laws affecting creditors' rights generally and as may be limited by
applicable federal or state securities laws.

         2.3      Consents and Approvals. Seller does not need to give any
notice to, make any filing with, or obtain any authorization, consent, or
approval of any government or governmental agency in order to consummate the
transactions contemplated by this Agreement, other than (a) such filings as are
required pursuant to applicable federal and state securities laws and blue sky
laws, which filings will be effected within the required statutory period; and
(b) such consents, approvals, orders or authorizations the failure of which to
be made or obtained would not have any change or effect that is or is reasonably
likely to be materially adverse to the financial condition, business or results
of operations of Seller or impair the ability of Seller to perform its
obligations in any material respect.

         2.4      Non-Contravention. Neither the execution and the delivery of
this Agreement, nor the consummation of the transactions contemplated hereby
will violate in any material respect any constitution, statute, regulation,
rule, injunction, judgment, order, decree, ruling, charge, or other restriction
of any government, governmental agency, or court to which Seller is subject or
any provision of its certificate of incorporation or bylaws. Except as obtained
prior to the Closing, no approval, waiver or consent by Seller under any
instrument, contract or


                                       2
<PAGE>

agreement to which Seller is a party is necessary to consummate the transactions
contemplated hereby.

         2.5      Title; Ownership. The Shares that are being purchased by Buyer
hereunder, when issued, sold and delivered in accordance with the terms of this
Agreement for the consideration expressed herein, will be duly and validly
issued, fully paid and nonassessable and will be free of restrictions on
transfer, other than restrictions on transfer under this Agreement and under
applicable state and federal securities laws. The Common Stock issuable upon
exercise of the Warrants purchased under this Agreement has been duly and
validly reserved for issuance and, upon issuance in accordance with the terms of
the Warrant, will be duly and validly issued, fully paid and nonassessable and
will be free of restrictions on transfer, other than restrictions on transfer
under this Agreement, the Warrant and under applicable state and federal
securities laws.

         2.6      Offering. Subject to the truth and accuracy of Buyer's
representations set forth in Article 3, the offer, sale and issuance of the
Shares as contemplated by this Agreement are exempt from the registration
requirements of the Securities Act of 1933, as amended (the "Act"), and the
qualification or registration requirements of the federal securities laws or
other applicable blue sky laws.

3.       REPRESENTATIONS AND WARRANTIES OF BUYER

         Buyer represents and warrants to Seller the following:

         3.1      Authorization of Transaction. Buyer has full power, capacity
and authority to execute and deliver this Agreement and to perform his
respective obligations hereunder. This Agreement constitutes the valid and
legally binding obligation of Buyer, enforceable in accordance with its terms
and conditions, except as enforceability may be limited by general equitable
principles, bankruptcy, insolvency, reorganization, moratorium or other laws
affecting creditors' rights generally and as may be limited by applicable
federal or state securities laws.

         3.2      Consents and Approvals. Buyer need not give any notice to,
make any filing with, or obtain any authorization, consent, or approval of any
government or governmental agency in order to consummate the transactions
contemplated by this Agreement.

         3.3      Non-Contravention. Neither the execution and the delivery of
this Agreement, nor the consummation of the transactions contemplated hereby
will violate in any material respect any constitution, statute, regulation,
rule, injunction, judgment, order, decree, ruling, charge, or other restriction
of any government, governmental agency, or court to which Buyer is subject. No
approval, waiver or consent by Buyer under any instrument, contract or agreement
to which Buyer or any of its affiliates is a party is necessary to consummate
the transactions contemplated hereby.

         3.4      Purchase for Entirely Own Account. This Agreement is made with
Buyer in reliance upon Buyer's representation to Seller, which by Buyer's
execution of this Agreement


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<PAGE>

Buyer hereby confirms, that the Shares to be received by Buyer and the Common
Stock issuable upon exercise of the Warrant (collectively, the "Securities")
will be acquired for investment for Buyer's own account, not as a nominee or
agent, and not with a view to the resale or distribution of any part thereof,
and that Buyer has no present intention of selling, granting any participation
in or otherwise distributing the same. By executing this Agreement, Buyer
further represents that Buyer does not have any contract, undertaking, agreement
or arrangement with any person to sell, transfer or grant participations to such
person or to any third person, with respect to any of the Securities.

         3.5      Disclosure of Information. Buyer has had an opportunity to
review Seller's filings under the Act and the Securities Exchange Act of 1934,
as amended, and has received all the information he considers necessary or
appropriate for deciding whether to purchase the Shares and the Warrants. Buyer
further represents that he has had an opportunity to ask questions and receive
answers from Seller regarding such filings, the terms and conditions of the
offering of the Shares and the Warrants and the business, properties, prospects
and financial condition of Seller.

         3.6      Investment Experience. Buyer is an investor in securities of
companies in the development stage and acknowledges that he is able to fend for
himself, can bear the economic risk of his investment, and has such knowledge
and experience in financial or business matters that he is capable of evaluating
the merits and risks of the investment in the Shares and the Warrants.

         3.7      Residence; Accredited Investor. Buyer's principal residence is
Venezuela. Buyer is an "accredited investor" within the meaning of Securities
and Exchange Commission ("SEC") Rule 501 of Regulation D, as presently in
effect.

         3.8      Restricted Securities. Buyer understands that the Securities
he is purchasing are characterized as "restricted securities" under the federal
securities laws inasmuch as they are being acquired from Seller in a transaction
not involving a public offering and that under such laws and applicable
regulations such Securities may be resold without registration under the Act
only in certain limited circumstances. In the absence of an effective
registration statement covering the Securities (or the Common Stock issued on
exercise of the Warrant) or an available exemption from registration under the
Act, the Shares (and any Common Stock issued on exercise of the Warrant) must be
held indefinitely. In this connection, Buyer represents that he is familiar with
SEC Rule 144, as presently in effect, and understands the resale limitations
imposed thereby and by the Act, including without limitation the Rule 144
condition that current information about Seller be available to the public.


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<PAGE>

         3.9      Legends. It is understood that the certificates evidencing the
Securities may bear the following legend:

         "THE SHARES REPRESENTED BY THIS INSTRUMENT HAVE NOT BEEN
         REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE
         "SECURITIES ACT"), OR ANY STATE SECURITIES LAWS AND MAY NOT
         BE OFFERED, SOLD, PLEDGED OR OTHERWISE TRANSFERRED OR
         DISPOSED OF UNLESS AND UNTIL SUCH SECURITIES ARE REGISTERED
         UNDER THE SECURITIES ACT AND APPLICABLE STATE SECURITIES LAWS
         OR AN OPINION OF LEGAL COUNSEL IS DELIVERED TO THE COMPANY
         STATING THAT AN EXEMPTION FROM SUCH REGISTRATION IS
         AVAILABLE."

         3.10     Advisors. Buyer has reviewed with his own tax advisors the
federal, state and local tax consequences of this investment, where applicable,
and the transactions contemplated by this Agreement. Buyer acknowledges that he
has had the opportunity to review this Agreement, the Warrant and the
transactions contemplated by this Agreement with Buyer's own legal counsel.
Buyer is relying solely on his legal counsel and tax advisors and not on any
statements or representations of Seller or any of the Seller's agents for legal
or tax advice with respect to this investment or the transactions contemplated
by this Agreement.

4.       CONDITIONS TO CLOSING

         4.1      Conditions to Obligations of Buyer. The obligation of Buyer to
consummate the transactions to be performed by it in connection with the Closing
is subject to satisfaction of the following conditions:

                  (a)      the representations and warranties set forth in
Article 2 shall be true and correct in all material respects at and as of the
Closing Date;

                  (b)      Seller shall have performed and complied with all of
its covenants hereunder in all material respects through the Closing;

                  (c)      All authorizations, approvals or permits, if any, of
any governmental authority or regulatory body of the United States or of any
state that are required prior to the lawful issuance and sale of the Securities
pursuant to this Agreement shall be duly obtained and effective as of the
Closing;

                  (d)      no statute, rule, regulation, executive order,
decree, temporary restraining order, preliminary or permanent injunction or
other order enacted, entered, promulgated, enforced or issued by any court of
competent jurisdiction or other governmental entity preventing the consummation
of the transactions contemplated hereby shall be in effect; and

                  (e)      all actions to be taken by Seller in connection with
consummation of the transactions contemplated hereby and all certificates,
opinions, instruments, and other documents required to effect the transactions
contemplated hereby will be reasonably satisfactory in form and substance to
Buyer.

         Buyer may waive any condition specified in this Section 4.1 if he
executes a writing so stating at or prior to the Closing.


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<PAGE>

         4.2      Conditions to Obligations of Seller. The obligation of Seller
to consummate the transactions to be performed by it in connection with the
Closing is subject to satisfaction of the following conditions:

                  (a)      the representations and warranties set forth in
Article 3 shall be true and correct in all material respects at and as of the
Closing Date;

                  (b)      Buyer shall have performed and complied with all of
his covenants hereunder in all material respects through the Closing;

                  (c)      All authorizations, approvals or permits, if any, of
any governmental authority or regulatory body of the United States or of any
state that are required in connection with the lawful issuance and sale of the
Securities pursuant to this Agreement shall be duly obtained and effective as of
the Closing;

                  (d)      no statute, rule, regulation, executive order,
decree, temporary restraining order, preliminary or permanent injunction or
other order enacted, entered, promulgated, enforced or issued by any court of
competent jurisdiction or other governmental entity preventing the consummation
of the transactions contemplated hereby shall be in effect;

                  (e)      all actions to be taken by Buyer in connection with
consummation of the transactions contemplated hereby and all certificates,
opinions, instruments, and other documents required to effect the transactions
contemplated hereby will be reasonably satisfactory in form and substance to
Seller; and

                  (f)      Buyer shall have acknowledged the repayment of
Seller's debt as the Purchase Price.

         Seller may waive any condition specified in this Section 4.2 if it
executes a writing so stating at or prior to the Closing.

5.       REGISTRATION RIGHTS.

         5.1      Registration by the Company. Subject to the terms and
conditions of this Agreement, the Seller shall file with the SEC within thirty
(30) days of the date of this Agreement a registration statement on Form SB-2
under the Act (the "Registration Statement") for the registration of the resale
by the Buyer of the Registrable Securities (as defined below). The Seller shall
use reasonable best efforts to cause such filed Registration Statement to become
and remain effective (pursuant to Rule 415 under the Act or otherwise); prepare
and file with the SEC such amendments and supplements to such Registration
Statement and the prospectus used in connection therewith as may be necessary to
keep such Registration Statement effective during the term of this Agreement;
and comply in all material respects with the provisions of the Act with respect
to the disposition of all Registrable Securities covered by such Registration


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<PAGE>

Statement during such period in accordance with the intended methods of
disposition by the Buyer. If Seller fails to comply with this Section 5.1 and
the Registration Statement is not declared effective by the SEC within 90 days
of the date of this Agreement, then, as relief for damages to the Buyer by
reason of any such delay, for each full 30-day period occurring after such
90-day period in which the Registration Statement fails to become effective,
Seller shall issue to Buyer 154,310 shares of Common Stock (the "Additional
Shares"). Any Additional Shares issued to Buyer pursuant to this Section 5.1
shall constitute liquidated damages for the failure of Seller to cause the
Registration Statement to become effective and upon such issuance of the
Additional Shares, Buyer shall be deemed to have released Seller for any such
failure to comply. Notwithstanding the foregoing, Seller shall not be in breach
of this Section 5.1 and no Additional Shares shall be required to be issued to
Buyer by Seller if any delay is attributed to changes required by the Buyer in
the Registration Statement with respect to information relating to the Buyer,
including, without limitation, changes to the plan of distribution. The Seller
may at any time elect, in his sole discretion, to waive his right to the
Additional Shares if the Registration Statement is not declared effective by the
SEC. It is a condition precedent to the obligations of the Seller under this
Section 5.1 that Buyer shall furnish to the Seller in writing such information
regarding the Buyer, the Common Stock and the intended method of disposition
thereof as the Seller shall reasonably request and as shall be required in
connection with the action to be taken by the Seller. So long as the Seller
complies with this Section 5.1, the Buyer shall have no right to take any action
to restrain, enjoin or otherwise delay any registration as the result of any
controversy that might arise with respect to the interpretation or
implementation of this Article 5. "Registrable Securities" shall mean the Shares
and the shares of Common Stock issued under the Warrant and any shares of Common
Stock issued as a dividend, stock split or other distribution with respect to or
in exchange for or in replacement of such Securities; provided, however, that
Registrable Securities shall not include any shares of Common Stock (a) which
have previously been registered or which have been sold to the public either
pursuant to a registration statement or Rule 144, (b) which have been sold in a
private transaction in which the transferor's rights under this Agreement are
not assigned or are not assignable or (c) the registration rights with respect
to such shares have been terminated pursuant to Section 5.3

         5.2      Market Standoff Rights. Buyer agrees that in connection with
an underwritten sale of shares of Common Stock to the public effected pursuant
to a registration statement filed with, and declared effective by, the SEC under
the Act, if requested by the Seller and the managing underwriters in such
offering, not to effect any public sale or distribution or other transfer or
disposal (including encumbrances) of any of the Buyer's securities (other than
securities acquired in or after such offering), including a sale pursuant to
Rule 144 (except as part of such underwritten offering), for a period of up to
180 days after the closing date of such underwritten offering. The Seller may
impose stop-transfer instructions with respect to the Registrable Securities (or
other securities) subject to the foregoing restriction until the end of such
180-day period; provided, however, that the foregoing obligation shall be
conditioned upon all officers and directors of the Seller entering into similar
agreements and not being released from such agreements at any time before or
during such 180-day period.


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<PAGE>

         5.3      Termination of Registration Rights. The right of Buyer to
request registration or inclusion in any registration pursuant to this Article 5
and the obligations of the Seller under this Article 5 shall terminate upon the
earlier of (a) if all of the Registrable Securities held by the Buyer may
immediately be sold under Rule 144 during any 90-day period or (b) the third
anniversary of the date hereof.

         5.4      Indemnification. If any Registrable Securities are included in
a Registration Statement under this Agreement:

                  (a)      To the extent permitted by law, the Seller will
defend, indemnify and hold harmless the Buyer and any underwriter (as defined in
the Act) for the Buyer and each person, if any, who controls the Buyer or such
underwriter within the meaning of the Act, from and against any and all loss,
damage, liability, cost and expense to which the Buyer or any such underwriter
or controlling person may become subject under the Act or otherwise, insofar as
such losses, damages, liabilities, costs or expenses are caused by any untrue
statement or alleged untrue statement of any material fact contained in such
registration statement, any prospectus contained therein or any amendment or
supplement thereto, or arise out of or are based upon the omission or alleged
omission to state therein a material fact required to be stated therein or
necessary to make the statements therein, in light of the circumstances in which
they were made, not misleading (each, a "Violation"); provided, however, that
the Seller will not be liable in any such case to the extent that any such loss,
damage, liability, cost or expenses arises out of or is based upon an untrue
statement or alleged untrue statement or omission or alleged omission so made in
conformity with information furnished by the Buyer, such underwriter or such
controlling person in writing specifically for use in the preparation thereof.

                  (b)      To the extent permitted by law, the Buyer will
defend, indemnify and hold harmless the Seller and any underwriter (as defined
in the Act) and each person, if any, who controls the Seller or such underwriter
within the meaning of the Act, from and against any and all loss, damage,
liability, cost and expense to which the Seller or any such underwriter or
controlling person may become subject under the Act or otherwise, insofar as
such losses, damages, liabilities, costs or expenses are caused by any
Violation, in each case to the extent such Violation arises out of or is based
upon an untrue statement or alleged untrue statement of any material fact or
omission or alleged omission to state therein a material fact so made in
conformity with information furnished by the Buyer, such underwriter or such
controlling person in writing specifically for use in the preparation of a
registration statement, any prospectus contained therein or any amendment or
supplement thereto.

                  (c)      Promptly after receipt by an indemnified party under
this Section 5.4 of notice of the commencement of any action (including any
governmental action), such indemnified party shall, if a claim in respect
thereof is to be made against any indemnifying party under this Section 5.4,
deliver to the indemnifying party a written notice of the commencement thereof
and the indemnifying party shall have the right to participate in, and, to the
extent the indemnifying party so desires, jointly with any other indemnifying
party similarly noticed, to assume the defense thereof with counsel mutually
satisfactory to the parties;


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<PAGE>

provided, however, that an indemnified party (together with all other
indemnified parties which may be represented without conflict by one counsel)
will have the right to retain one separate counsel, with the reasonable fees and
expenses to be paid by the indemnifying party, if representation of such
indemnified party by the counsel retained by the indemnifying party is
inappropriate due to actual or potential differing interests between such
indemnified party and any other party represented by such counsel in such
proceeding. The failure to deliver written notice to the indemnifying party
within a reasonable time of the commencement of any such action, if materially
prejudicial to its ability to defend such action, shall relieve such
indemnifying party of any liability to the indemnified party under this Section
5.4, but the omission so to deliver written notice to the indemnifying party
shall not relieve it of any liability that it may have to any indemnified party
otherwise than under this Section 5.4.

         5.5      (a) Subject to Section 5.5(b), (i) Notify the Buyer of
Registrable Securities covered by the Registration Statement if, to its
knowledge, the Registration Statement, at the time it or any amendment thereto
became effective, contained an untrue statement of a material fact or omitted to
state a material fact required to be stated therein or necessary to make the
statements therein not misleading, and, as promptly as practicable, prepare and
file with the SEC a post-effective amendment to the Registration Statement such
that the Registration Statement, as so amended, shall 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 misleading, and
(ii) notify the Buyer of Registrable Securities covered by the Registration
Statement, at any time when a prospectus relating thereto is required to be
delivered under the Act, if, to its knowledge, the prospectus included in the
Registration Statement, as then in effect, includes an untrue statement of a
material fact or omits to state a material fact required to be stated therein or
necessary to make the statements therein, in light of the circumstances under
which they were made, not misleading so that, amended or supplemented, such
prospectus shall not include 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, in light of the circumstances under which they were made,
not misleading. Buyer agrees that upon receipt of any notice from Seller
pursuant to this Section 5.5(a), Buyer will promptly discontinue Buyer's
disposition of Registrable Securities pursuant to the Registration Statement
covering such Registrable Securities until Buyer shall have received notice from
Seller that the Registration Statement has been amended and/or copies of the
supplemented or amended prospectus contemplated by this Section 5.5(a) have been
furnished. If so directed by Seller, the Buyer of Registrable Securities will
deliver to Seller all copies, other than permanent file copies, in such Buyer's
possession of the prospectus covering such Registrable Securities at the time of
receipt of such notice.

         (b)      If (i) there is material non-public information regarding the
Seller which the Seller's Board of Directors reasonably determines not to be in
the Seller's best interest to disclose and which the Seller is not otherwise
required to disclose or (ii) there is a significant business opportunity
(including, but not limited to, the acquisition or disposition of assets (other
than in the ordinary course of business) or any merger, consolidation, tender
offer or other similar transaction) available to the Seller which the Seller's
Board of Directors reasonably determines not to be in the Seller's best interest
to


                                       9
<PAGE>

disclose and which the Seller would be required to disclose under the
Registration Statement, then the Seller may suspend the sale of Registrable
Securities under the Registration Statement for a period not to exceed
forty-five (45) consecutive days.

6.       GENERAL PROVISIONS

         6.1      Survival. The warranties, representations and covenants of the
Parties contained in or made pursuant to this Agreement shall survive the
execution and delivery of this Agreement and the Closing.

         6.2      Expenses. Each of the Parties will bear its own costs and
expenses (including legal fees and expenses) incurred in connection with this
Agreement and the transactions contemplated hereby.

         6.3      Finder. Each Party represents that it neither is nor will be
obligated for any finders' fee or commission in connection with this
transaction. Buyer agrees to indemnify and to hold harmless Seller from any
liability for any commission or compensation in the nature of a finders' fee
(and the costs and expenses of defending against such liability or asserted
liability) for which Buyer or any of its officers, partners, employees or
representatives is responsible.

         6.4      Entire Agreement. This Agreement (including the documents
referred to herein) constitutes the entire agreement among the Parties and
supersedes any prior understandings, agreements, or representations by or among
the Parties, written or oral, to the extent they relate in any way to the
subject matter hereof.

         6.5      Amendments and Waivers. No amendment of any provision of this
Agreement shall be valid unless the same shall be in writing and signed by the
Parties. No waiver by any Party of any default, misrepresentation, or breach of
warranty or covenant hereunder, whether intentional or not, shall be deemed to
extend to any prior or subsequent default, misrepresentation, or breach of
warranty or covenant hereunder or affect in any way any rights arising by virtue
of any prior or subsequent such occurrence.


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<PAGE>

         6.5      Notices. All notices, requests, demands, claims, and other
communications hereunder will be in writing. Any notice, request, demand, claim,
or other communication hereunder shall be deemed duly given if (and then two
business days after) it is sent by (a) confirmed facsimile; (b) overnight
delivery; or (c) registered or certified mail, return receipt requested, postage
prepaid, and addressed to the intended recipient as set forth below:

         If to Seller:                           Copy to:
         ------------                            -------

         Cell Robotics International, Inc.       Baker & McKenzie
         2715 Broadbent Parkway N.E.             2001 Ross Avenue, Suite 2300
         Albuquerque, New Mexico 87107           Dallas, TX 75201
         Attn: President                         Attn: W. Crews Lott
         Facsimile: (505) 344-8112               Facsimile: (214) 978-3099

         If to Buyer:
         -----------
         Oton M. Tisch
         Apartado 76949
         Caracas 1070,  Venezuela
         Facsimile: (011) 58212-239-7828

Any Party may send any notice, request, demand, claim, or other communication
hereunder to the intended recipient at the address set forth above using any
other means (including personal delivery, expedited courier, messenger service,
telecopy, telex, ordinary mail, or electronic mail), but no such notice,
request, demand, claim, or other communication shall be deemed to have been duly
given unless and until it actually is received by the intended recipient. Any
Party may change the address to which notices, requests, demands, claims, and
other communications hereunder are to be delivered by giving the other Parties
notice in the manner herein set forth.

         6.6      Succession and Assignment. This Agreement shall be binding
upon and inure to the benefit of the Parties named herein and their respective
successors and permitted assigns. No Party may assign either this Agreement or
any of its rights, interests, or obligations hereunder without the prior written
approval of the other Parties.

         6.7      Choice of Law; Section Headings. This Agreement shall be
governed by and construed in accordance with the domestic laws of the State of
New Mexico without giving effect to any choice or conflict of law provision or
rule (whether of the State of New Mexico or any other jurisdiction) that would
cause the application of the laws of any jurisdiction other than the State of
New Mexico. The section headings contained in this Agreement are for reference
purposes only and shall not affect the meaning or interpretation of this
Agreement.

         6.8      Jurisdiction. Any legal action or proceeding with respect to
this Agreement shall be brought in any New Mexico state or federal court sitting
in Bernalillo County, New Mexico, and, by execution and delivery of this
Agreement, Buyer and Seller hereby accept for themselves and in respect of their
property, generally and unconditionally, the jurisdiction of the aforesaid
courts. Buyer and Seller hereby irrevocably waive any objection, including,
without limitation, any objection to the laying of venue or based on the grounds
of forum non conveniens, which they may now or hereafter have to the bringing of
any such action or proceeding in such respective jurisdictions.


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<PAGE>

         6.9      Severability. Any term or provision of this Agreement that is
invalid or unenforceable in any situation in any jurisdiction shall not affect
the validity or enforceability of the remaining terms and provisions hereof or
the validity or enforceability of the offending term or provision in any other
situation or in any other jurisdiction.

         6.10     Counterparts. This Agreement may be executed in any number of
counterparts, each of which shall be deemed to be an original and all of which
together shall be deemed to be one and the same instrument.

         6.11     Authorship. The Parties agree that the terms and language of
this Agreement were the result of negotiations between the Parties and, as a
result, there shall be no presumption that any ambiguities in this Agreement
shall be resolved against either Party. Any controversy over construction of
this Agreement shall be decided without regard to events of authorship or
negotiation.

                                      *****

         The Parties have executed and delivered this Agreement as of the date
indicated in the first sentence of this Agreement.

CELL ROBOTICS INTERNATIONAL, INC.



By: /s/ Gary Oppedahl
   --------------------------------------
   Gary Oppedahl
   President and Chief Executive Officer



By: /s/ Oton M. Tisch
   ---------------------------------------
   Oton M. Tisch


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