<PAGE>

                                                                   EXHIBIT 10.28

THIS WARRANT AND THE SECURITIES ISSUABLE UPON EXERCISE OF THIS WARRANT HAVE NOT
BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES
ACT") OR ANY STATE SECURITIES LAWS, AND MAY NOT BE SOLD, OFFERED FOR SALE,
ASSIGNED, TRANSFERRED OR OTHERWISE DISPOSED OF, UNLESS REGISTERED PURSUANT TO
THE PROVISIONS OF THE SECURITIES ACT OR AN OPINION OF COUNSEL IS OBTAINED
STATING THAT SUCH DISPOSITION IS IN COMPLIANCE WITH AN AVAILABLE EXEMPTION FROM
SUCH REGISTRATION.

SERIES Q                                                     WARRANT TO PURCHASE
NO. 003                                           375,000 SHARES OF COMMON STOCK

                               WARRANT TO PURCHASE
                                  COMMON STOCK
                                       OF
                              NEOPROBE CORPORATION

This certifies that, for value received, David C. Bupp, or his registered
permitted assigns (collectively, the "HOLDER"), is entitled to purchase from
NEOPROBE CORPORATION, (the "COMPANY"), a corporation organized and existing
under the laws of the State of Delaware, subject to the terms and conditions set
forth below, at any time on or after 9:00 A.M., Eastern time, on March 8, 2004
of this Warrant, and before 5:00 P.M., Eastern time, on the Expiration Date (as
defined below), the number of fully paid and nonassessable shares of common
stock, $0.001 par value, of the Company ("COMMON STOCK") stated above at the
Purchase Price (as defined below). The Purchase Price and the number of shares
purchasable hereunder are subject to adjustment as provided below. This Warrant
is issued pursuant to the terms of the First Amendment to 8.5% Senior Secured
Note Purchase Agreement, dated as of March 8, 2004, as the same may be amended,
modified or supplemented pursuant to the terms thereof (the "PURCHASE
AGREEMENT"), and is subject to the terms thereof.

                                    ARTICLE I

                                   DEFINITIONS

                  Section 1.1. (a) The term "Business Day" as used in this
Warrant means a day other than a Saturday, Sunday or other day on which national
banking associations whose principal offices are located in the State of Ohio
are authorized by law to remain closed.

                  (b)      The term "Expiration Date" as used in this Warrant
means the date of expiration of the sixty month period immediately after the
Exercise Date (as defined in Section 2.1 hereof) or, if that day is not a
Business Day, as defined above, at or before 5:00 P.M. Eastern time on the next
following Business Day.

                  (c)      "Person" means any person or entity including any
corporation, a limited liability company, an association, a partnership, an
organization, an individual, a governmental or political subdivision thereof or
a governmental agency.

                  (c)      The term "Purchase Price" as used in this Warrant
shall mean Fifty Cents ($0.50), as may be adjusted pursuant to the terms of
Article III hereof.

                  (e)      "Register," "registered," and "registration" refer to
a registration effected by preparing and filing one or more registration
statements of the Company in compliance with the 1933 Act or any successor rule
providing for offering securities, and the declaration or ordering of
effectiveness of such registration statement(s) by the United States Securities
and Exchange Commission (the "SEC").

<PAGE>

                  (f)      "Registrable Securities" means the Warrant Shares
which have been, or which may from time to time be issued, upon exercise of the
Warrants.

                  (g)      "Registration Statement" means the registration
statement of the Company which the Company has agreed to file hereunder
registering the offer and sale by Holder to the public of the Registrable
Securities.

                  (d)      The term "Warrant" as used in this Warrant means this
Warrant and Warrants of like tenor to purchase up to the amount of Warrant
Shares (as defined below), indicated on the first page of the Warrant.

                  (e)      The term "Warrant Shares" as used in this Warrant
means the shares of Common Stock issuable upon exercise of the Warrant.

                                   ARTICLE II

                        DURATION AND EXERCISE OF WARRANT

                  Section 2.1. This Warrant may be exercised at any time after
9:00 A.M., Eastern time, on March 8, 2004 (the "EXERCISE DATE") and before 5:00
P.M., Eastern time, on the Expiration Date.

                  Section 2.2. (a) The Holder may exercise this Warrant in whole
or in part (but not in denominations of fewer than 5,000 Warrant Shares except
upon an exercise of the Warrant with respect to the remaining balance of Warrant
Shares purchasable hereunder at the time of exercise) by surrender of this
Warrant, with the Purchase Form (attached hereto) duly executed, to the Company
at its corporate office, together with the applicable Purchase Price of each
Warrant Share being purchased in lawful money of the United States, or by
certified check or official bank check payable in United States dollars to the
order of the Company, subject to compliance with all the other conditions set
forth in this Warrant.

                  (b)      Upon receipt of this Warrant with the Purchase Form
duly executed and accompanied by payment of the aggregate Purchase Price for the
shares of Common Stock for which this Warrant is being exercised, the Company
shall cause to be issued certificates for the total number of whole shares (as
provided in Section 3.2) of Common Stock for which this Warrant is being
exercised in such denominations as the Holder may request, each registered in
the name of the Holder or such other name as may be designated by the Holder,
and thereafter the Company will promptly deliver, at its sole cost and expense,
those certificates to the Holder, together with any other securities or property
to which the Holder is entitled upon such exercise.

                  (c)      If the Holder exercises this Warrant with respect to
fewer than all the shares of Common Stock that may be purchased by exercise of
this Warrant, the Company will execute a new Warrant for the balance of the
shares of Common Stock that may be purchased by exercise of this Warrant and
deliver that new Warrant to the Holder.

                                   ARTICLE III

                      ADJUSTMENT OF PURCHASE PRICE, NUMBER
                         OF SHARES OR NUMBER OF WARRANTS

                  Section 3.1. The Purchase Price, the number and type of
securities issuable on exercise of this Warrant and the number of Warrants
outstanding are subject to adjustment from time to time as follows:

                                        2

<PAGE>

                  (a)      If the Company issues any shares of its Common Stock
as a dividend on its Common Stock, the Purchase Price then in effect will be
proportionately reduced at the opening of business on the day following the date
fixed for the determination of stockholders entitled to receive the dividend or
other distribution. For example, if the Company distributes one share of Common
Stock as a dividend on each outstanding share of Common Stock the Purchase Price
would be reduced by 50%. If the Company issues as a dividend on its Common Stock
any securities which are convertible into, or exchangeable for, shares of its
Common Stock, such dividend will be treated as a dividend of the Common Stock
into which the securities may be converted, or for which they may be exchanged,
and the Purchase Price shall be proportionately reduced.

                  (b)      If the outstanding shares of Common Stock are
subdivided into a greater number of shares of Common Stock, then the Purchase
Price will be proportionately reduced at the opening of business on the day
following the day when the subdivision becomes effective, and if the outstanding
shares of the Common Stock are combined into a smaller number of shares of
Common Stock, the Purchase Price will be proportionately increased at the
opening of business on the day following the day when the combination becomes
effective.

                  (c)      If by reason of a merger, consolidation,
reclassification or similar corporate event, the holders of the Common Stock
receive securities or assets other than Common Stock, upon exercise of this
Warrant after that corporate event, the Holder of this Warrant will be entitled
to receive the securities or assets the Holder would have received if the Holder
had exercised this Warrant immediately before the first such corporate event and
not disposed of the securities or assets received as a result of that or any
subsequent corporate event.

                  Section 3.2. Upon each adjustment of the applicable Purchase
Price pursuant to Section 3.1 hereof, this Warrant will, after the adjustment,
evidence the right to purchase, at the adjusted Purchase Price, the number of
shares (calculated to the nearest hundredth) obtained by (i) multiplying the
number of shares issuable on exercise of this Warrant immediately prior to the
adjustment by the Purchase Price in effect immediately prior to the adjustment
and (ii) dividing the resulting product by the Purchase Price in effect
immediately after the adjustment. However, the Company will not be required to
issue a fractional share or to make any payment in lieu of issuing a fractional
share.

                  Section 3.3. Whenever the Purchase Price or the number of
shares or type of securities issuable on exercise of this Warrant is adjusted as
provided in this Article III, the Company will compute the adjusted Purchase
Price and the adjusted number of Warrant Shares and will prepare a certificate
signed by its President or any Vice President, and by its Treasurer or Secretary
setting forth the effective date of the adjustment, the adjusted Purchase Price
and the adjusted number of Warrant Shares and showing in reasonable detail the
facts upon which the adjustments were based and mail a copy of that certificate
to the Holder by first class mail, postage prepaid, addressed to the registered
Holder of this Warrant at the address of such Holder as shown on the books of
the Company.

                  Section 3.4. If at any time when this Warrant is outstanding
the Company:

                  (a)      declares any cash dividend (or authorizes any other
distribution) on its Common Stock;

                  (b)      authorizes the granting to the holders of its Common
Stock of rights to subscribe for or purchase any shares of its capital stock or
assets, other than a dividend payable solely in shares of Common Stock;

                  (c)      authorizes a reclassification, split or combination
of the Common Stock, or a consolidation or merger to which the Company is a
party or a sale or transfer of all or substantially all the assets of the
Company; or

                                        3

<PAGE>

                  (d)      authorizes a voluntary or involuntary dissolution,
liquidation or winding up of the Company;

then, in any one or more of said cases, the Company shall give, by certified or
registered mail, postage prepaid, addressed to the registered Holder of this
Warrant at the address of such Holder as shown on the books of the Company, (i)
at least 30 days' prior written notice of the date on which the books of the
Company shall close or a record shall be taken for such dividend, distribution
or subscription rights or for determining rights to vote in respect of any such
dissolution, liquidation or winding-up; (ii) at least 10 days' prior written
notice of the date on which the books of the Company shall close or a record
shall be taken for determining rights to vote in respect of any such
reorganization, reclassification, consolidation, merger or sale, and (iii) in
the case of any such reorganization, reclassification, consolidation; merger,
sale, dissolution, liquidation or winding-up, at least 30 days' written notice
of the date when the same shall take place. Any notice given in accordance with
clause (i) above shall also specify, in the case of any such dividend,
distribution or option rights, the date on which the holders of Common Stock
shall be entitled thereto. Any notice given in accordance with clause (iii)
above shall also specify the date on which the holders of Common Stock shall be
entitled to exchange their Common Stock for securities or other property
deliverable upon such reorganization, reclassification, consolidation, merger,
sale, dissolution, liquidation or winding-up, as the case may be.

                  Section 3.5. The form of this Warrant need not be changed
because of any change in the Purchase Price or in the number of Warrant Shares,
and Warrants issued after that change may continue to describe the Purchase
Price and the number of Warrant Shares which were described in this Warrant as
initially issued.

                                   ARTICLE IV

                          OTHER PROVISIONS RELATING TO
                            RIGHTS OF WARRANT HOLDER

                  Section 4.1. If this Warrant is duly exercised, the Holder
will for all purposes be deemed to become the holder of record of the Warrant
Shares as to which this Warrant is exercised, and the certificate for such
shares will be dated, on the date this Warrant is surrendered for exercise and
the Purchase Price paid in accordance with Section 2.2 hereof, except that if
such date is not a Business Day, the Holder will be deemed to become the record
holder of the Warrant Shares, and the certificate will be dated, on the next
succeeding Business Day. The Holder will not be entitled to any rights as a
holder of the Warrant Shares, including the right to vote and to receive
dividends, until the Holder becomes or is deemed to become the holder of such
shares pursuant to the terms hereof.

                  Section 4.2. (a) The Company covenants and agrees that it will
at all times reserve and keep available for the exercise of this Warrant a
sufficient number of authorized but unissued shares of Common Stock to permit
the exercise in full of this Warrant.

                  (b)      The Company covenants that all shares of Common Stock
issued upon exercise of this Warrant and against payment of the Purchase Price
will be duly authorized, validly issued, fully paid and nonassessable and free
from all pre-emptive rights of any stockholder and free of all taxes, liens and
charges with respect to the issue thereof. The Company covenants that it will
take all reasonable action as may be necessary to assure that such Common Stock
may be issued as provided herein without violation of any applicable law or
regulation, or of any requirements of any domestic securities exchange or
automated quotation system upon which the Common Stock may be listed, or any
agreement to which the Company may be a party.

                  Section 4.3. Notices to the Holder relating to this Warrant
will be effective on the earliest of actual receipt or the third business day
after mailing by first class mail (which shall be certified or

                                        4

<PAGE>

registered, return receipt requested), postage prepaid, addressed to the Warrant
Holder at the address shown on the books of the Company.

                  Section 4.4. The issuance of certificates for shares of Common
Stock upon the exercise of the Warrant shall be made without charge to the
Holder for any issue tax in respect thereof; provided, however, that the Company
shall not be required to pay any tax which may be payable in respect of any
transfer involved in the issuance and delivery of any certificate in a name
other than that of the then Holder of the Warrant being exercised.

                                    ARTICLE V

                           TREATMENT OF WARRANT HOLDER

                  Prior to presentation of this Warrant for registration of
transfer, the Company may treat the Holder for all purposes as the owner of this
Warrant and the Company will not be affected by any notice to the contrary.

                                   ARTICLE VI

                 COMBINATION, EXCHANGE AND TRANSFER OF WARRANTS

                  Section 6.1. Any transfer permitted under this Warrant will be
made by surrender of this Warrant to the Company at its principal office with
the Form of Assignment (attached hereto) duly executed. In such event the
Company will, without charge, execute and deliver a new Warrant to and in the
name of the assignee named in the instrument of assignment and this Warrant will
promptly be canceled.

                  Section 6.2. This Warrant may be divided or combined with
other Warrants which carry the same rights upon presentation of them at the
principal office of the Company together with a written notice signed by the
Holder, specifying the names and denominations in which new Warrants are to be
issued.

                  Section 6.3. Upon receipt by the Company of evidence
reasonably satisfactory to it of the loss, theft, destruction or mutilation of
this Warrant, and, in the case of loss, theft or destruction, of reasonably
satisfactory indemnification, or, in the case of mutilation, upon surrender of
the mutilated Warrant, the Company will execute and deliver a new Warrant
bearing the same terms and date as the lost, stolen or destroyed Warrant, which
will thereupon become void.

                                        5

<PAGE>

                                   ARTICLE VII

                               REGISTRATION RIGHTS

                  Section 7.1. (a) For a period of eighteen (18) months
following the date of this Warrant, except as otherwise provided in this Section
7.1(a), the Company shall notify all Holders in writing at least fifteen (15)
days prior to the filing of any registration statement under the Securities Act
for purposes of a public offering of securities of the Company (including, but
not limited to, registration statements relating to secondary offerings of
securities of the Company, but excluding registration statements (i) relating to
employee benefit plans, or (ii) relating solely to corporate reorganizations or
other transactions under Rule 145 of the Securities Act), and will afford Holder
an opportunity to include in such registration statement all or some of the
Registrable Securities held by Holder. If Holder desires to include in any such
registration statement any of the Registrable Securities held by it, Holder
shall, within fifteen (15) days after the receipt of the above-described notice
from the Company, so notify the Company in writing. Such notice shall state the
intended method of disposition of the Registrable Securities held by Holder.

                           (1)      If the registration statement as to which
the Company gives notice under this Section 7.1(a) is for an underwritten
offering, the Company shall so advise the Holder. In such event, the right of
any Holder to include any of its Registrable Securities in such registration
shall be conditioned upon such Holder's participation in such underwriting and
the inclusion of Holder's Registrable Securities in the underwriting to the
extent provided herein. If Holder proposes to distribute Registrable Securities
through such underwriting the Holder shall enter into an underwriting agreement
in customary form with the underwriter or underwriters selected for such
underwriting by the Company. Notwithstanding any other provision of this
Agreement, if the managing underwriter determines in good faith that marketing
factors require a limitation of the number of shares to be underwritten, the
number of shares that may be included in the underwriting shall be allocated as
determined by the underwriter and the Company.

                           (2)      The Company shall have the right to
terminate or withdraw any registration initiated by it under this Section 7.1(a)
prior to the effectiveness of such registration whether or not Holder has
elected to include Registrable Securities in such registration. In such an
event, the Registration Expenses of such withdrawn registration shall be borne
by the Company in accordance with Section 7.4 hereof.

                  (b)      Subject to the conditions of this Section 7.1(b), if
anytime after eighteen (18) months following the date of this Warrant, the
Company shall receive a written request from Holder that the Company file a
registration statement under the Securities Act covering the registration of
some or all of the Registrable Securities then held by Holder, then the Company
shall, within thirty (30) days of the receipt thereof, subject to the
limitations of this Section 7.1, effect the registration under the Securities
Act of all Registrable Securities that Holder requests to be registered.

                  (c)      The Company shall, as required by applicable
securities regulations, from time to time file with the SEC, pursuant to Rule
424 promulgated under the 1933 Act, the prospectus and prospectus supplements,
if any, to be used in connection with sales of the Registrable Securities under
the Registration Statement. Holder and his counsel shall have a reasonable
opportunity to review and comment upon such prospectus prior to its filing with
the SEC.

                  Section 7.2. With respect to the Registration Statement, the
Company shall have the following obligations:

                  (a)      The Company shall prepare and file with the SEC such
amendments (including post-effective amendments) and supplements to the
Registration Statement and the prospectus used in connection with the
Registration Statement, which prospectus is to be filed pursuant to Rule 424
promulgated under the 1933 Act, as may be necessary to keep the Registration
Statement effective.

                                        6

<PAGE>

                  (b)      The Company shall permit Holder to review and comment
upon the Registration Statement and all amendments and supplements thereto at
least two Business Days prior to their filing with the SEC. Holder shall provide
the Company with any comments or corrections to the Registration Statement, or
any amendments or supplements thereto, within two Business Days from the date
Holder receives the final version thereof.

                  (c)      The Company shall furnish to Holder, (i) promptly
after the same is prepared and filed with the SEC, at least one copy of the
Registration Statement and any amendment(s) thereto, including financial
statements and schedules, and all exhibits, (ii) upon the effectiveness of any
registration statement, 10 copies of the prospectus included in such
registration statement and all amendments and supplements thereto (or such other
number of copies as Holder may reasonably request) and (iii) such other
documents, including copies of any preliminary or final prospectus, as Holder
may reasonably request from time to time in order to facilitate the disposition
of the Registrable Securities owned by Holder.

                  (d)      The Company shall use commercially reasonable efforts
to (i) register and qualify the Registrable Securities covered by a registration
statement under such other securities or "blue sky" laws of such jurisdictions
in the United States as Holder reasonably request, (ii) prepare and file in
those jurisdictions, such amendments (including post-effective amendments) and
supplements to such registrations and qualifications as may be necessary to
maintain the effectiveness thereof, (iii) take such other actions as may be
necessary to maintain such registrations and qualifications in effect at all
times during while the Registration Statement is effective, and (iv) take all
other actions reasonably necessary or advisable to qualify the Registrable
Securities for sale in such jurisdictions; provided, however, that the Company
shall not be required in connection therewith or as a condition thereto to (x)
qualify to do business in any jurisdiction where it would not otherwise be
required to qualify but for this Section 3(d), (y) subject itself to general
taxation in any such jurisdiction, or (z) file a general consent to service of
process in any such jurisdiction.

                  (e)      As promptly as practicable after becoming aware of
such event or facts, the Company shall notify Holder in writing of the happening
of any event or existence of such facts as a result of which 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, and promptly prepare
and file with the SEC and with all other applicable "blue sky" authorities a
supplement or amendment to such registration statement to correct such untrue
statement or omission, and deliver 10 copies of such supplement or amendment to
Holder (or such other number of copies as Holder may reasonably request). The
Company shall also promptly notify Holder in writing (i) when a prospectus or
any prospectus supplement or post-effective amendment has been filed, and when
the Registration Statement or any post-effective amendment has become effective,
(ii) of any request by the SEC for amendments or supplements to the Registration
Statement or related prospectus or related information, and (iii) of the
Company's reasonable determination that a post-effective amendment to the
Registration Statement would be appropriate.

                  (f)      The Company shall use its commercially reasonable
efforts to prevent the issuance of any stop order or other suspension of
effectiveness of any registration statement, or the suspension of the
qualification of any Registrable Securities for sale in any jurisdiction and, if
such an order or suspension is issued, to obtain the withdrawal of such order or
suspension at the earliest possible moment and to notify Holder of the issuance
of such order and the resolution thereof or its receipt of actual notice of the
initiation or threat of any proceeding for such purpose.

                                        7

<PAGE>

                  Section 7.3. (a) Holder shall promptly furnish to the Company
such information regarding itself, the Registrable Securities held by it and the
intended method of disposition of the Registrable Securities held by it as shall
be reasonably requested by the Company to effect the registration of such
Registrable Securities, including information to be included in the Registration
Statement, prospectus and all amendments and supplements thereto, and shall
execute such documents in connection with such registration as the Company may
reasonably request.

                  (b)      Holder agrees to cooperate with the Company as
reasonably requested by the Company in connection with the preparation and
filing of the Registration Statement, any amendment thereto, or any amendment or
supplement to the prospectus.

                  (c)      Holder agrees that, upon receipt of any notice from
the Company of the happening of any event or existence of facts of the kind
described in Section 7.2(f) or the first sentence of 7.2(e), Holder will
immediately discontinue disposition of Registrable Securities until Holder's
receipt of the copies of the supplemented or amended prospectus contemplated by
Section 7.2(f) or the first sentence of 7.2(e).

                  Section 7.4. All reasonable expenses, other than sales or
brokerage commissions, incurred in connection with registrations, filings or
qualifications pursuant to Sections 7.1(a) and (b), including, without
limitation, all registration, listing and qualification fees, printing and
accounting fees, and fees and disbursements of counsel for the Company, shall be
paid by the Company.

                  Section 7.5. (a) To the fullest extent permitted by law, the
Company will, and hereby does, indemnify, hold harmless and defend each Holder,
each Person, if any, who controls Holder, the members, the directors, officers,
partners, employees, agents, representatives of Holder and each Person, if any,
who controls Holder within the meaning of the 1933 Act or the Securities
Exchange Act of 1934, as amended (the "1934 ACT") and their respective
successors and assigns (each, an "Indemnified Person"), against any losses,
claims, damages, liabilities, judgments, fines, penalties, charges, costs,
attorneys' fees, amounts paid in settlement or expenses, joint or several,
(collectively, "Claims") incurred in investigating, preparing or defending any
action, claim, suit, inquiry, proceeding, investigation or appeal taken from the
foregoing by or before any court or governmental, administrative or other
regulatory agency, body or the SEC, whether pending or threatened, whether or
not an indemnified party is or may be a party thereto ("Indemnified Damages"),
to which any of them may become subject insofar as such Claims (or actions or
proceedings, whether commenced or threatened, in respect thereof) arise out of
or are based upon: (i) any untrue statement or alleged untrue statement of a
material fact in the Registration Statement, or any post-effective amendment
thereto or in any filing made in connection with the qualification of the
offering under the securities or other "blue sky" laws of any jurisdiction in
which Registrable Securities are offered ("Blue Sky Filing"), or the omission or
alleged omission to state a material fact required to be stated therein or
necessary to make the statements therein not misleading, (ii) any untrue
statement or alleged untrue statement of a material fact contained in the final
prospectus (as amended or supplemented, if the Company files any amendment
thereof or supplement thereto with the SEC) or the omission or alleged omission
to state therein any material fact necessary to make the statements made
therein, in light of the circumstances under which the statements therein were
made, not misleading, or (iii) any violation or alleged violation by the Company
of the 1933 Act, the 1934 Act, any other law, including, without limitation, any
state securities law, or any rule or regulation thereunder relating to the offer
or sale of the Registrable Securities pursuant to the Registration Statement
(the matters in the foregoing clauses (i) through (iii) being, collectively,
"Violations"). The Company shall reimburse each Indemnified Person promptly as
such expenses are incurred and are due and payable, for any legal fees or other
reasonable expenses incurred by them in connection with investigating or
defending any such Claim. Notwithstanding anything to the contrary contained
herein, the indemnification agreement contained in this Section 6(a): (i) shall
not apply to a Claim by an Indemnified Person arising out of or based upon a
Violation which occurs as a result of any untrue statement or omission of a
material fact by Holder in information provided to the Company expressly for use
in connection with the preparation of the Registration Statement, or any
amendment thereof or supplement thereto; (ii) with respect to any superseded
prospectus, shall not inure to the benefit of any such person from whom the
person asserting any such Claim purchased the Registrable Securities

                                        8

<PAGE>

that are the subject thereof (or to the benefit of any person controlling such
person) if the untrue statement or omission of material fact contained in the
superseded prospectus was corrected in the revised prospectus, as then amended
or supplemented, prior to the purchase, and if such revised prospectus was
timely made available by the Company pursuant to Section 7.2(c) or Section
7.2(e); (iii) shall not be available to the extent such Claim is based on a
failure of an Indemnified Person to deliver or to cause to be delivered the
prospectus made available by the Company, if such prospectus was timely made
available by the Company pursuant to Section 7.2(c) or Section 7.2(e); and (iv)
shall not apply to amounts paid in settlement of any Claim if such settlement is
effected without the prior written consent of the Company, provided that such
consent shall not be unreasonably withheld. Such indemnity shall remain in full
force and effect regardless of any investigation made by or on behalf of the
Indemnified Person and shall survive any transfer of the Registrable Securities
by Holder pursuant to Section 7.5.

                  (b)      In connection with the Registration Statement, Holder
agrees to indemnify, hold harmless and defend, to the same extent and in the
same manner as is set forth in Section 6(a), the Company, each of its directors,
each of its officers who signs the Registration Statement, each Person, if any,
who controls the Company within the meaning of the 1933 Act or the 1934 Act and
their respective successors and assigns (collectively and together with an
Indemnified Person, an "Indemnified Party"), against any Claim or Indemnified
Damages to which any of them may become subject, under the 1933 Act, the 1934
Act or otherwise, insofar as such Claim or Indemnified Damages arise out of or
are based upon any Violation, in each case to the extent, and only to the
extent, that such Violation (i) occurs in reliance upon and in conformity with
information furnished to the Company by Holder expressly for use in connection
with the Registration Statement, prospectus or amendment or supplement thereto,
(ii) arises from an untrue statement or omission of material fact contained in a
superseded prospectus, if the untrue statement or omission of material fact
contained in the superseded prospectus was corrected in the revised prospectus,
as then amended or supplemented, if such revised prospectus was timely made
available by the Company pursuant to Section 7.2(c) or Section 7.2(e), (iii)
arises as a result of such Holder 's failure to deliver or to cause to be
delivered the prospectus made available by the Company, if such prospectus was
timely made available by the Company pursuant to Section 7.2(c) or Section
7.2(e), or (iv) arises from the offer or sale or Registrable Securities under
the securities or other "blue sky" laws of any jurisdiction in which Holder has
not requested the Company to register and qualify the Registrable Securities
pursuant to Section 7.2(d); and, subject to Section 7.4, Holder will reimburse
promptly as such expenses are incurred and are due and payable any legal fees or
other reasonable expenses incurred by them in connection with investigating or
defending any such Claim; provided, however, that the indemnity agreement
contained in this Section 7.5 and the agreement with respect to contribution
contained in Section 7 shall not apply to amounts paid in settlement of any
Claim if such settlement is effected without the prior written consent of
Holder, provided that such consent shall not be unreasonably withheld. Such
indemnity shall remain in full force and effect regardless of any investigation
made by or on behalf of such Indemnified Party and shall survive the transfer of
the Registrable Securities by Holder pursuant to Section 7.8.

                  (c)      Promptly after receipt by an Indemnified Person or
Indemnified Party under this Section 7.5 of notice of the commencement of any
claim, investigation, inquiry, action or proceeding (including any governmental
action or proceeding) involving a Claim, such Indemnified Person or Indemnified
Party shall, if a Claim in respect thereof is to be made against any
indemnifying party under this Section 7.5, 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
control of the defense thereof with counsel mutually satisfactory to the
indemnifying party and the Indemnified Person or the Indemnified Party, as the
case may be; provided, however, that an Indemnified Person or Indemnified Party
shall have the right to retain its own counsel with the fees and expenses to be
paid by the indemnifying party, if, in the reasonable opinion of counsel
retained by the indemnifying party, the representation by such counsel of the
Indemnified Person or Indemnified Party and the indemnifying party would be
inappropriate due to actual or potential differing interests between such
Indemnified Person or Indemnified Party and any other party represented by such
counsel in such proceeding. The Indemnified Party or Indemnified Person shall
cooperate fully with the indemnifying party in connection with any negotiation
or defense of any such action or claim by the indemnifying party and shall
furnish to the indemnifying party all information

                                        9

<PAGE>

reasonably available to the Indemnified Party or Indemnified Person which
relates to such action or claim. The indemnifying party shall keep the
Indemnified Party or Indemnified Person fully apprised at all times as to the
status of the defense or any settlement negotiations with respect thereto. No
indemnifying party shall be liable for any settlement of any action, claim or
proceeding effected without its written consent, provided, however, that the
indemnifying party shall not unreasonably withhold, delay or condition its
consent. No indemnifying party shall, without the consent of the Indemnified
Party or Indemnified Person, consent to entry of any judgment or enter into any
settlement or other compromise which does not include as an unconditional term
thereof the giving by the claimant or plaintiff to such Indemnified Party or
Indemnified Person of a release from all liability in respect to such claim or
litigation. Following indemnification as provided for hereunder, the
indemnifying party shall be subrogated to all rights of the Indemnified Party or
Indemnified Person with respect to all third parties, Persons, firms or
corporations relating to the matter for which indemnification has been made. The
failure to deliver written notice to the indemnifying party within a reasonable
time of the commencement of any such action shall not relieve such indemnifying
party of any liability to the Indemnified Person or Indemnified Party under this
Section 6, except to the extent that the indemnifying party is prejudiced in its
ability to defend such action.

                  Section 7.6. To the extent any indemnification by an
indemnifying party is prohibited or limited by law, the indemnifying party
agrees to make the maximum contribution with respect to any amounts for which it
would otherwise be liable under Section 7.5 to the fullest extent permitted by
law; provided, however, that: (i) no seller of Registrable Securities guilty of
fraudulent misrepresentation (within the meaning of Section 11(f) of the 1933
Act) shall be entitled to contribution from any seller of Registrable Securities
who was not guilty of fraudulent misrepresentation; and (ii) contribution by any
seller of Registrable Securities shall be limited in amount to the net amount of
proceeds received by such seller from the sale of such Registrable Securities.

                  Section 7.7. With a view to making available to Holder the
benefits of Rule 144 promulgated under the 1933 Act or any other similar rule or
regulation of the SEC that may at any time permit Holder to sell securities of
the Company to the public without registration ("Rule 144"), until the Warrants
have been fully exercised or have expired, the Company agrees to:

                  (a)      make and keep public information available, as those
terms are understood and defined in Rule 144;

                  (b)      file with the SEC in a timely manner all reports and
other documents required of the Company and its officers under the 1933 Act and
the 1934 Act so long as the Company remains subject to such requirements and the
filing of such reports and other documents is required for the applicable
provisions of Rule 144; and

                  (c)      furnish to Holder so long as Holder owns Registrable
Securities, promptly upon request, (i) a written statement by the Company that
it and its officers have complied with the reporting and or disclosure
provisions of Rule 144, the 1933 Act and the 1934 Act, (ii) a copy of the most
recent annual or quarterly report of the Company and such other reports and
documents so filed by the Company and its officers, and (iii) such other
information as may be reasonably requested to permit Holder to sell such
securities pursuant to Rule 144 without registration.

                  Section 7.8. The Company shall not assign this Agreement or
any rights or obligations hereunder without the prior written consent of Holder,
including by merger or consolidation. Holder may not assign its rights under
this Agreement without the written consent of the Company, other than to a
permitted transferee of Holder's Warrant.

                                       10

<PAGE>

                                  ARTICLE VIII

                                  OTHER MATTERS

                  Section 8.1. (a) Except for transfers of this Warrant to a
member of the original Holder's parents, brothers, sisters, spouse or lineal
descendants, or to trusts for the benefit thereof, pursuant to which the
original Holder retains the sole authority to take any action hereunder on
behalf of such transferees, this Warrant may not be sold, transferred, pledged,
hypotecated or otherwise disposed of by the Holder, other than with respect to
the entire unexercised portion thereof. In addition to the foregoing
restriction, this Warrant and any Warrant Shares may not be sold, transferred,
pledged, hypothecated or otherwise disposed of except as follows: (i) to a
person who, in the reasonable opinion of counsel to the Company, is a person to
whom this Warrant or the Warrant Shares may legally be transferred without
registration and without the delivery of a current prospectus under the
Securities Act of 1933 (the "SECURITIES ACT") with respect thereto, and then
only against receipt of an agreement of such person to comply with the
provisions of this Section 8.1(a) with respect to any resale or other
disposition of such securities; or (ii) to any person upon delivery of a
prospectus then meeting the requirements of the Securities Act relating to such
securities and the offering thereof for such sale or disposition, and thereafter
to all successive assignees.

                  (b)      Unless the Warrant Shares have been registered under
the Securities Act, upon exercise of any of the Warrant and the issuance of any
of the Warrant Shares, all certificates representing Warrant Shares shall bear
on the face thereof substantially the following legend:

                  The SALE OR OTHER DISPOSITION OF THE SECURITIES REPRESENTED BY
         THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF
         1933, AS AMENDED, AND MAY NOT BE SOLD, OFFERED FOR SALE, ASSIGNED,
         TRANSFERRED OR OTHERWISE DISPOSED OF, UNLESS REGISTERED PURSUANT TO THE
         PROVISIONS OF THAT ACT OR UNLESS AN OPINION OF COUNSEL TO THE ISSUER IS
         OBTAINED STATING THAT SUCH DISPOSITION IS IN COMPLIANCE WITH AN
         AVAILABLE EXEMPTION FROM SUCH REGISTRATION.

                  (c)      The Holder shall have no right to require the Company
to register the Warrant Shares under the Securities Act of 1933 or any state
securities law, except to the extent provided in the Registration Rights
Agreement of even date herewith.

                  Section 8.2. All the covenants and provisions of this Warrant
by or for the benefit of the Company will bind and inure to the benefit of its
successors and assigns.

                  Section 8.3. All notices and other communications under this
Warrant must be in writing. Any notice or communication to the Company will be
effective upon the earlier of actual receipt or the third business day after
mailing by first class mail (which shall be certified or registered, return
receipt requested), postage prepaid, addressed (until another address is
designated by the Company) as follows:

                                    Neoprobe Corporation
                                    425 Metro Place North, Suite 300
                                    Dublin, OH 43017
                                    Attn: Chief Financial Officer
                                    (tele) (614) 793-7500
                                    (fax) (614) 793-7522

                  Any notice or demand authorized by this Warrant to be given or
made by the Company to the Holder must be given in accordance with Section 4.3.

                                       11

<PAGE>

                  Section 8.4. The corporate laws of the State of Delaware shall
govern all issues concerning the relative rights of the Company and its
stockholders. All other questions concerning the construction, validity,
enforcement and interpretation of this Warrant shall be governed by the internal
laws of the State of Ohio, without giving effect to any choice of law or
conflict of law provision or rule (whether of the State of Ohio or any other
jurisdictions) that would cause the application of the laws of any jurisdiction
other than the State of Ohio. Each party hereby irrevocably waives personal
service of process and consents to process being served in any such suit, action
or proceeding by mailing a copy thereof to such party at the address for such
notices to it under this Warrant and agrees that such service shall constitute
good and sufficient service of process and notice thereof. Nothing contained
herein shall be deemed to limit in any way any right to serve process in any
manner permitted by law. If any provision of this Warrant shall be invalid or
unenforceable in any jurisdiction, such invalidity or unenforceability shall not
affect the validity or enforceability of the remainder of this Warrant in that
jurisdiction or the validity or enforceability of any provision of this Warrant
in any other jurisdiction.

                  Section 8.5. Nothing in this Warrant will give any person,
corporation or other entity other than the Company and the Holder any right or
claim under this Warrant, and all agreements in this Warrant will be for the
sole benefit of the Company, the Holder, and their respective successors and
permitted assigns.

                  Section 8.6. The Article headings in this Warrant are for
convenience only, are not part of this Warrant and will not affect the
interpretation of its terms.

                  Section 8.7. Any controversy, claim or dispute arising out of
or relating to this Warrant or the breach, termination, enforceability or
validity of this Warrant, including the determination of the scope or
applicability of the agreement to arbitrate set forth in this Section 8.7 shall
be determined exclusively by binding arbitration in the City of Columbus, Ohio.
The arbitration shall be governed by the rules and procedures of the American
Arbitration Association (the "AAA") under its Commercial Arbitration Rules and
its Supplementary Procedures for Large, Complex Disputes; provided that persons
eligible to be selected as arbitrators shall be limited to attorneys-at-law each
of whom (a) is on the AAA's Large, Complex Case Panel or a Center for Public
Resources ("CPR") Panel of Distinguished Neutrals, or has professional
credentials comparable to those of the attorneys listed on such AAA and CPR
Panels, and (b) has actively practiced law (in private or corporate practice or
as a member of the judiciary) for at least 15 years in the State of Ohio
concentrating in either general commercial litigation or general corporate and
commercial matters. Any arbitration proceeding shall be before one arbitrator
mutually agreed to by the parties to such proceeding (who shall have the
credentials set forth above) or, if the parties are unable to agree to the
arbitrator within 15 business days of the initiation of the arbitration
proceedings, then by the AAA. No provision of, nor the exercise of any rights
under, this Section 8.7 shall limit the right of any party to request and obtain
from a court of competent jurisdiction in the State of Ohio, County of Franklin
(which shall have exclusive jurisdiction for purposes of this Section 8.7)
before, during or after the pendency of any arbitration, provisional or
ancillary remedies and relief including injunctive or mandatory relief or the
appointment of a receiver. The institution and maintenance of an action or
judicial proceeding for, or pursuit of, provisional or ancillary remedies shall
not constitute a waiver of the right of any party, even if it is the plaintiff,
to submit the dispute to arbitration if such party would otherwise have such
right. Each of the parties hereby submits unconditionally to the exclusive
jurisdiction of the state and federal courts located in the County of Franklin,
State of Ohio for purposes of this provision, waives objection to the venue of
any proceeding in any such court or that any such court provides an inconvenient
forum and consents to the service of process upon it in connection with any
proceeding instituted under this Section 8.7 in the same manner as provided for
the giving of notice under this Warrant. Judgment upon the award rendered may be
entered in any court having jurisdiction. The parties hereby expressly consent
to the nonexclusive jurisdiction of the state and federal courts situated in the
County of Franklin, State of Ohio for this purpose and waive objection to the
venue of any proceeding in such court or that such court provides an
inconvenient forum. The arbitrator shall have the power to award recovery of all
costs (including attorneys' fees, administrative fees, arbitrators' fees and
court costs) to the prevailing party. The arbitrator shall not have power, by
award or otherwise, to vary any of the provisions of this Warrant.

                                       12

<PAGE>

                  IN WITNESS WHEREOF, this Warrant has been duly executed by the
Company as of March 8, 2004.

                                                     NEOPROBE CORPORATION

                                    By: /s/ Brent L. Larson
                                    --------------------------------------------
                                        Brent L. Larson
                                        Vice President-Finance and Chief
                                        Financial Officer

                                       13

<PAGE>

                                  PURCHASE FORM

                      To Be Executed By The Warrant Holder

To       Exercise The Warrant In Whole Or In Part:

To:      NEOPROBE CORPORATION

         The undersigned (_____________________________________________)

                                    Please insert Tax ID Number or other
                                    identifying number of Holder

hereby irrevocably elects to exercise the right of purchase represented by the
within Warrant for, and to purchase thereunder, ___________________ shares of
Common Stock of Neoprobe Corporation in the amount of $__________ The
undersigned requests that certificates for those shares of Common Stock be
issued as follows:

                  Name:________________________________________________

                  Address:_____________________________________________

                  Deliver to:__________________________________________

                  Address:_____________________________________________

                  Denominations:_______________________________________

and that, if the number of shares of Common Stock is not all the shares of
Common Stock purchasable by exercise of the Warrant, that a new Warrant for the
balance of the shares of Common Stock purchasable under the within Warrant be
registered in the name of, and delivered to, the undersigned at the address
stated below:

                  Address:_____________________________________________

                  Date:________________________________________________

                                    Signature:__________________________________

                                       14

<PAGE>

                               FORM OF ASSIGNMENT

                (To Be Executed Only Upon a Permitted Assignment)

FOR VALUE RECEIVED, the undersigned hereby sells, assigns, and transfers unto
____________________ the all of the undersigned's right, title and interest in
the within Warrant.

                                    Signature:__________________________________

Signature Guaranteed:

___________________________

                                       15