NEOPROBE CORPORATION Amended and Restated 10% Series B Senior Secured Convertible Promissory Note due December 26, 2011

Exhibit 10.3

THIS NOTE AND THE SHARES OF COMMON STOCK ISSUABLE UPON CONVERSION HEREOF HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “ACT”), OR APPLICABLE STATE SECURITIES LAWS, AND MAY NOT BE SOLD, TRANSFERRED, OR OTHERWISE DISPOSED OF IN THE ABSENCE OF SUCH REGISTRATION OR RECEIPT BY THE MAKER OF AN OPINION OF COUNSEL IN THE FORM, SUBSTANCE AND SCOPE REASONABLY SATISFACTORY TO THE MAKER THAT THIS NOTE AND THE SHARES OF COMMON STOCK ISSUABLE UPON CONVERSION HEREOF MAY BE SOLD, TRANSFERRED, OR OTHERWISE DISPOSED OF, UNDER AN EXEMPTION FROM REGISTRATION UNDER THE ACT AND SUCH STATE SECURITIES LAWS.

NEOPROBE CORPORATION

Amended and Restated 10% Series B Senior Secured Convertible Promissory Note

due December 26, 2011

Dated: April 16, 2008

Amended and Restated: July 24, 2009

For value received, NEOPROBE CORPORATION, a Delaware corporation (the “ Maker ”), hereby promises to pay to the order of Platinum-Montaur Life Sciences, LLC, 152 West 57th Street, New York, NY 10019 (together with its successors, representatives, and permitted assigns, the “ Holder ”), in accordance with the terms hereinafter provided, the principal amount of Three Million and 00/100 Dollars ($3,000,000.00), together with interest thereon. This Note is being issued pursuant to the Purchase Agreement, and the Exchange Agreement (as those terms are defined in Section 1.1 hereof).  The Maker has also issued to the Holder the Maker’s 10% Series A Senior Secured Convertible Promissory Note (“ Series A Note ”) and shares of the Maker’s 8% Series A Convertible Preferred Stock (“ Preferred Stock ”). This Note and the Series A Note, as amended and restated in connection with the Exchange Agreement, are collectively referred to herein as the “Notes.”

All payments under or pursuant to this Note shall be made in United States Dollars in immediately available funds to the Holder at the address of the Holder first set forth above or at such other place as the Holder may designate from time to time in writing to the Maker or by wire transfer of funds to the Holder’s account, instructions for which are attached hereto as Exhibit A. The outstanding principal balance of this Note shall be due and payable on December 26, 2011 (the “ Maturity Date ”) or at such earlier time as provided herein.

ARTICLE I

PAYMENT TERMS

1.1          Purchase Agreement .  This Note has been executed and delivered pursuant to the Securities Purchase Agreement, dated as of December 26, 2007 (the “Purchase Agreement ”), and the Securities Amendment and Exchange Agreement, dated as of July 24, 2009 (the “Exchange Agreement”), each by and among the Maker and the purchasers listed therein. Capitalized terms used and not otherwise defined herein shall have the meanings set forth for such terms in the Purchase Agreement.

1.2          Interest . Beginning on the original issuance date of this Note (the “ Issuance Date ”), the outstanding principal balance of this Note shall bear interest, in arrears, at a rate per annum equal to ten percent (10%), payable monthly on the first day of each calendar month (each, an “ Interest Payment Date ”) commencing February 1, 2008, at the option of the Maker in (A) cash or (B) in registered shares of Common Stock; provided, however, (i) payment of interest in shares of Common Stock may only occur if during the 20 Trading Days immediately prior to the applicable Interest Payment Date and through and including the date such shares of Common Stock are issued to the Holder all of the Equity Conditions, unless waived by the Holder in writing, have been met and the Maker shall have given the Holder notice in accordance with the notice requirements set forth below, and (ii) as to such Interest Payment Date, within two days after the Interest Payment Date, the Maker shall cause the physical delivery to the Holder   of a certificate representing the number of shares of Common Stock to be applied against such interest payment equal to the quotient of (x) the applicable interest payment divided by (y) 90% of the average VWAP for the five (5) Trading Days immediately preceding the Interest Payment Date.  Interest shall be computed on the basis of a 360-day year of twelve (12) 30-day months, shall compound monthly and shall accrue commencing on the Issuance Date.  Furthermore, upon the occurrence of an Event of Default (as defined in Section 2.1 hereof), the Maker will pay interest to the Holder, payable on demand, on the outstanding principal balance of and unpaid interest on the Note from the date of the Event of Default until such Event of Default is cured at the rate of the lesser of thirteen percent (13%) and the maximum applicable legal rate per annum.   Notwithstanding the above, the Maker may not issue a number of shares of Common Stock in excess of the Maximum Monthly Interest Share Amount toward the payment of Interest, as to all outstanding Series A Notes and Series B Notes, in the aggregate, during any rolling twenty (20) Trading Day period. For purposes hereof, “ Maximum Monthly Interest Share Amount ” means 20% of the aggregate dollar trading volume (as reported on Bloomberg) of the Common Stock on the principal Trading Market over the twenty (20) consecutive Trading Day period immediately prior to the applicable Interest Payment Date.

1.3          Payment of Principal; No Prepayment .   The Principal Amount hereof shall be paid in full on the Maturity Date or, if earlier, upon acceleration of this Note in accordance with the terms hereof. Any amount of principal repaid hereunder may not be reborrowed.  The Maker may not prepay any portion of the principal amount of this Note without the prior written consent of the Holder, which may be withheld in the Holder’s sole and absolute discretion.

1.4         Security Agreement .   The obligations of the Maker hereunder are secured by a continuing security interest in certain assets of the Maker pursuant to the terms of a Security Agreement dated as of December 26, 2007 by and between the Maker and the Holder, a Patent, Trademark and Copyright Security Agreement, dated as of December 26, 2007, by and among the Maker and the Maker’s subsidiaries, on the one hand, and the Holder, on the other hand, and a Blocked Account Control Agreement (“ Account Control Agreement ”) among the Maker, the Holder and U.S. Bank National Association (“ Bank ”), pursuant to the terms of Section 5.15 of the Purchase Agreement.

1.5          Payment on Non-Business Days .   Whenever any payment to be made shall be due on a Saturday, Sunday or a public holiday under the laws of the State of New York, such payment may be due on the next succeeding business day and such next succeeding day shall be included in the calculation of the amount of accrued interest payable on such date.

1.6          Transfer .   This Note may be transferred or sold, subject to the provisions of Section 5.8 hereof, or pledged, hypothecated or otherwise granted as security by the Holder.

1.7          Replacement .   Upon receipt of a duly executed, notarized and unsecured written statement from the Holder with respect to the loss, theft or destruction of this Note (or any replacement hereof) and a standard indemnity, or, in the case of a mutilation of this Note, upon surrender and cancellation of such Note, the Maker shall issue a new Note, of like tenor and amount, in lieu of such lost, stolen, destroyed or mutilated Note.

1.8          Use of Proceeds .   The Maker shall use the proceeds of this Note as set forth in the Purchase Agreement.

1.9          Allocation of Payments .  All payments to each of the Series B Holders under the Series B Notes shall be made pro rata among the Series B Holders based upon the aggregate unpaid principal amount of the Series B Notes held by them.

ARTICLE II

EVENTS OF DEFAULT; REMEDIES

2.1         Events of Default. The occurrence of any of the following events shall be an “ Event of Default ” under this Note:

(a)           any default in the payment of (i) the principal amount hereunder when due, or (ii) interest on, or liquidated damages in respect of, this Note, as and when the same shall become due and payable (whether on the Maturity Date or by acceleration or otherwise); or

(b)           the suspension from listing, without subsequent listing on any one of, or the failure of the Common Stock to be listed on at least one of the OTC Bulletin Board, the American Stock Exchange, the Nasdaq Global Select Market, the Nasdaq Global Market, the Nasdaq Capital Market or The New York Stock Exchange, Inc. for a period of more than five (5) consecutive Trading Days; or

(c)           the Maker shall fail to (i) timely deliver the shares of Common Stock upon conversion of the Note or any interest accrued and unpaid, (ii) file a Registration Statement in accordance with the terms of the Registration Rights Agreement or (iii) make the payment of any fees or other payments due under this Note, the Purchase Agreement, the Registration Rights Agreement or the other Transaction Documents, which failure is not remedied within five (5) business days after such performance is due; or

(d)           while the Registration Statement is required to be maintained effective pursuant to the terms of the Registration Rights Agreement, the effectiveness of the Registration Statement (as defined in the Registration Rights Agreement) lapses for any reason (including, without limitation, the issuance of a stop order) or is unavailable to the Holder for sale of the Registrable Securities (as defined in the Registration Rights Agreement) as provided in the Registration Rights Agreement (other than as a result of any breach of the Registration Rights Agreement or violation of law by any holder of the Notes, or their agents or Affiliates), and such lapse or unavailability continues for a period of ten (10) consecutive Trading Days,  provided  that the Maker has not exercised its rights pursuant to Section 3(n)   of the Registration Rights Agreement; or

(e)           default shall be made in the performance or observance of (i) any covenant, condition or agreement contained in this Note (other than is set forth in (a) through (d) above) and such default is not cured within ten (10) days after the earlier of (A) the date the Maker receives notice from the Holder of the occurrence thereof or (B) the date on which the Maker knew or should have known, if it had exercised reasonable diligence, of such default, or (ii) any material covenant, condition or agreement contained in the Purchase Agreement, Registration Rights Agreement, the Series A Note, or any other Transaction Document that is not covered by any other provisions of this Section 2.1 and such default is not cured within ten (10) days after the earlier of (A) the date the Maker receives notice from the Holder of the occurrence thereof or (B) the date on which the Maker knew or should have known, if it had exercised reasonable diligence, of such default; or

(f)           any material representation or warranty made by the Maker herein or in the Purchase Agreement, the Series A Note or any other Transaction Document shall prove to have been false or incorrect or breached in a material respect on the date as of which made; or

(g)            the Maker shall (i) default in any payment of any amount or amounts of principal of or interest on any Indebtedness (other than the Indebtedness hereunder) the aggregate principal amount of which Indebtedness, in the aggregate, exceeds $100,000, which default entitles the holder or holders of such Indebtedness to accelerate the maturity thereof, or (ii) default in the observance or performance of any other agreement or condition relating to any Indebtedness or contained in any instrument or agreement evidencing, securing or relating thereto, or any other event shall occur or condition exist, which default, event or condition continues beyond any applicable cure period, and the effect of which default, event or condition is to cause, or to permit the holder or holders or beneficiary or beneficiaries of such Indebtedness to cause with the giving of notice if required, such Indebtedness to become due prior to its stated maturity; or

(h)           the Maker shall (i) apply for or consent to the appointment of, or the taking of possession by, a receiver, custodian, trustee or liquidator of itself or of all or a substantial part of its property or assets, (ii) make a general assignment for the benefit of its creditors, (iii) commence a voluntary case under the United States Bankruptcy Code (as now or hereafter in effect) or under the comparable laws of any jurisdiction (foreign or domestic), (iv) file a petition seeking to take advantage of any bankruptcy, insolvency, moratorium, reorganization or other similar law affecting the enforcement of creditors’ rights generally, (v) acquiesce in writing to any petition filed against it in an involuntary case under United States Bankruptcy Code (as now or hereafter in effect) or under the comparable laws of any jurisdiction (foreign or domestic), (vi) admit in writing its inability to pay its debts as they become due, or (vii) take any action under the laws of any jurisdiction (foreign or domestic) analogous to any of the foregoing; or

(i)           a proceeding or case shall be commenced in respect of the Maker, without its application or consent, in any court of competent jurisdiction, seeking (i) the liquidation, reorganization, moratorium, dissolution, winding up, or composition or readjustment of its debts, (ii) the appointment of a trustee, receiver, custodian, liquidator or the like of it or of all or any substantial part of its assets in connection with the liquidation or dissolution of the Maker, or (iii) similar relief in respect of it under any law providing for the relief of debtors, and such proceeding or case described in clause (i), (ii) or (iii) shall continue undismissed, or unstayed and in effect, for a period of sixty (60) days or any order for relief shall be entered in an involuntary case under United States Bankruptcy Code (as now or hereafter in effect) or under the comparable laws of any jurisdiction (foreign or domestic) against the Maker or action under the laws of any jurisdiction (foreign or domestic) analogous to any of the foregoing shall be taken with respect to the Maker and shall continue undismissed, or unstayed and in effect for a period of sixty (60) days; or

(j)           at any point after 135 vital blue dye lymph nodes have been obtained from patients who have completed surgery and injection of the drug in the Phase 3 clinical trial of Lymphoseek (NEO3-05), the failure of Maker to achieve the primary objective in such trial of efficacy of Lymphoseek, which is the concordance of in-vivo detection rate of Lymphoseek and vital blue dye in tumor-draining sentinel lymph nodes as confirmed by pathology in at least ninety-three percent (93%) of such patients, determined in good faith by the Company and the Holder following a review of the unaudited trial data; or

(k)           the Bank shall provide written notice to the Maker or Holder of the Bank’s termination of the Account Control Agreement, and the Maker does not within forty-five (45) days following such notice (i) establish a replacement blocked account pursuant to Section 5.15 of the Purchase Agreement with another financial institution, on substantially the same terms contained in the Account Control Agreement, or as otherwise reasonably acceptable to Maker and Holder (the “Replacement Account”), (ii) transfer all funds held in the account subject to the Account Control Agreement to the Replacement Account, and (iii) provide evidence to the Holder that an instruction letter, substantially in the form of the Instruction Letter attached as Exhibit M to the Purchase Agreement, has been executed by each of the Maker and Ethicon, irrevocably instructing Ethicon to make payments under the Ethicon Agreement to the Replacement Account; or

(l)           the occurrence of any default or event of default under any other Note or the failure by the Maker to comply with its material obligations under the Certificate of Designations governing the terms of the Preferred Stock.

2.2           Remedies Upon An Event of Default .  If an Event of Default shall have occurred and shall be continuing, the Holder of this Note may at any time at its option declare the entire unpaid principal balance of this Note, together with all interest accrued hereon, due and payable, and thereupon, the same shall be accelerated and so due and payable, without presentment, demand, protest, or notice, all of which are hereby expressly unconditionally and irrevocably waived by the Maker; provided, however, that upon the occurrence of an Event of Default described above, the Holder, in its sole and absolute discretion, may (a) demand that the entire principal amount of this Note then outstanding and all accrued and unpaid interest thereon shall be converted into shares of Common Stock at the Conversion Price per share on the Trading Day immediately preceding the date the Holder demands conversion pursuant to this clause, or (b) exercise or otherwise enforce any one or more of the Holder’s rights, powers, privileges, remedies and interests under this Note (including, if applicable, pursuant to Section 3.7 hereof), the Purchase Agreement, the Registration Rights Agreement or applicable law.  No course of delay on the part of the Holder shall operate as a waiver thereof or otherwise prejudice the right of the Holder. No remedy conferred hereby shall be exclusive of any other remedy referred to herein or now or hereafter available at law, in equity, by statute or otherwise. No notice or other action of Holder shall be required in the case of an Event of Default set forth in Sections 2.1(h) or (i), and, in such event, the outstanding principal balance and accrued interest hereunder shall be automatically due and payable.

ARTICLE III

CONVERSION; ANTIDILUTION

3.1         Conversion Option .  At any time and from time to time on or after the Issuance Date, the entire outstanding principal balance of this Note (the “ Conversion Amount ”) shall be convertible (in whole or in part), at the option of the Holder (the “ Conversion Option ”), into such number of fully paid and non-assessable shares of Common Stock (the “ Conversion Rate ”) as is determined by dividing (x) that portion of the Conversion Amount as of such date that the Holder elects to convert by (y) the Conversion Price (as defined in Section 3.2 hereof) then in effect on the date on which the Holder faxes a notice of conversion (the “ Conversion Notice ”), duly executed, to the Maker (facsimile number (614) 793-7520, Attn.: Brent L. Larson, Vice President - Finance) (the “ Conversion Date ”);   provided, however, that the Conversion Price shall be subject to adjustment as described in Section 3.5 below.  The Holder shall deliver this Note to the Maker at the address designated in the Purchase Agreement at such time that this Note is fully converted. With respect to partial conversions of this Note, the Maker shall keep written records of the amount of this Note converted as of each Conversion Date.

3.2          Conversion Price . The term “Conversion Price” shall mean $0.36, subject to adjustment under Section 3.5 hereof.

3.3          Mechanics of Conversion .

(a)           Not later than three (3) Trading Days after any Conversion Date, the Maker or its designated transfer agent, as applicable, shall issue and deliver to the Depository Trust Company (“DTC”) account on the Holder’s behalf via the Deposit Withdrawal Agent Commission System (“DWAC”) as specified in the Conversion Notice, the number of shares of Common Stock to which the Holder shall be entitled upon such conversion, registered in the name of the Holder or its designee.  In the alternative, not later than three (3) Trading Days after any Conversion Date, the Maker shall deliver to the applicable Holder by express courier a certificate or certificates which shall be free of restrictive legends and trading restrictions (other than those required pursuant to the Purchase Agreement) representing the number of shares of Common Stock being acquired upon the conversion of this Note (the “ Delivery Date ”). Notwithstanding the foregoing to the contrary, the Maker or its transfer agent shall only be obligated to issue and deliver the shares to the DTC on the Holder’s behalf via DWAC (or certificates free of restrictive legends) if such conversion is in connection with a sale by the Holder and the Holder has complied with the applicable prospectus delivery requirements or an exemption from such registration requirements (each as evidenced by documentation furnished to and reasonably satisfactory to the Maker). If in the case of any Conversion Notice such certificate or certificates are not delivered to or as directed by the Holder by the Delivery Date, the Holder shall be entitled by written notice to the Maker at any time on or before its receipt of such certificate or certificates thereafter, to rescind such conversion, in which event the Maker shall immediately return this Note tendered for conversion, whereupon the Maker and the Holder shall each be restored to their respective positions immediately prior to the delivery of such notice of revocation, except that any amounts described in Sections 3.3(b) and (c) shall be payable through the date notice of rescission is given to the Maker.

(b)           The Maker understands that a delay in the delivery of the shares of Common Stock upon conversion of this Note beyond the Delivery Date could result in economic loss to the Holder. If the Maker fails to deliver to the Holder such shares via DWAC (or, if applicable, certificates), or fails to deliver unlegended certificates representing such shares if required pursuant to Section 3.3(a) hereof,  by the Delivery Date, the Maker shall pay to such Holder, in cash, an amount per Trading Day for each Trading Day until such shares are delivered via DWAC or certificates are delivered (if applicable), together with interest on such amount at a rate of 10% per annum, accruing until such amount and any accrued interest thereon is paid in full, equal to the greater of (A) (i) 1% of the aggregate principal amount of the Notes requested to be converted for the first five (5) Trading Days after the Delivery Date and (ii) 2% of the aggregate principal amount of the Notes requested to be converted for each Trading Day thereafter and (B) $2,000 per day (which amount shall be paid as liquidated damages and not as a penalty). Nothing herein shall limit a Holder’s right to pursue actual damages for the Maker’s failure to deliver certificates representing shares of Common Stock upon conversion within the period specified herein and such Holder shall have the right to pursue all remedies available to it at law or in equity (including, without limitation, a decree of specific performance and/or injunctive relief). Notwithstanding anything to the contrary contained herein, the Holder shall be entitled to withdraw a Conversion Notice, and upon such withdrawal the Maker shall only be obligated to pay the liquidated damages accrued in accordance with this Section 3.3(b) through the date the Conversion Notice is withdrawn.

3.4          Ownership Cap and Certain Conversion Restrictions .

(a)           Notwithstanding anything to the contrary set forth in Section 3 of this Note, at no time may the Holder convert all or a portion of this Note if the number of shares of Common Stock to be issued pursuant to such conversion would exceed, when aggregated with all other shares of Common Stock owned by the Holder at such time, the number of shares of Common Stock which would result in the Holder beneficially owning (as determined in accordance with Section 13(d) of the Exchange Act and the rules thereunder) more than 4.99% of all of the Common Stock outstanding at such time; provided, however, that upon the Holder providing the Maker with sixty-one (61) days notice (pursuant to Section 4.1 hereof) (the “ Waiver Notice ”) that the Holder waives the limitations contained  in this Section 3.4(a) with regard to any or all shares of Common Stock issuable upon conversion of this Note, this Section 3.4(a) will be of no force or effect with regard to all or a portion of the Note referenced in the Waiver Notice.

(b)           Notwithstanding anything to the contrary set forth in Section 3 of this Note, at no time may the Holder convert all or a portion of this Note if the number of shares of Common Stock to be issued pursuant to such conversion, when aggregated with all other shares of Common Stock owned by the Holder at such time, would result in the Holder beneficially owning (as determined in accordance with Section 13(d) of the Exchange Act and the rules thereunder) in excess of 9.99% of the then issued and outstanding shares of Common Stock outstanding at such time;  provided,  however, that upon the Holder providing the Maker with a Waiver Notice that the Holder waives the limitations contained in this Section 3.4(b) with regard to any or all shares of Common Stock issuable upon conversion of this Note, this Section 3.4(b) shall be of no force or effect with regard to all or a portion of the Note referenced in the Waiver Notice.

(c)           Notwithstanding the above, the provisions of Section 3.4(a) and 3.4(b) shall not be applicable when calculating any adjustment to the Conversion Price hereunder or any other adjustments under Section 3.5 hereof.

3.5          Adjustment of Conversion Price .

(a)           Until the Note has been paid in full or converted in full, the Conversion Price shall be subject to adjustment from time to time as follows (but shall not be increased, other than pursuant to Section 3.5(a)(i) hereof):