SUBSCRIPTION AGREEMENT

Exhibit 10.31

SUBSCRIPTION AGREEMENT

          Subscription Agreement (together with the schedules and exhibits hereto, this “ Agreement ”), dated as of _________, 2008, by and between BioDrain Medical, Inc., a Minnesota corporation (“the Company ”), and each of the Persons (as defined below) who has executed a signature page to this Agreement (each a “ Purchaser ,” and together, the “ Purchasers ”).

W I T N E S S E T H:

           WHEREAS, the Company desires to issue and sell to the Purchasers, and the Purchasers desire to purchase from the Company, a minimum of $0.8 million and a maximum of $1.7 million of Units (as such term is defined below) as set forth below.

          NOW, THEREFORE, in consideration of the premises and the mutual covenants and agreements hereinafter contained, and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, intending to be legally bound, the parties hereto hereby agree as follows:

1. Offer and Sale of Securities.

          1.1 The Offering . The Company is offering for sale of a minimum of 2,285,715 and a maximum of 4,857,144 units of Company securities. Each “unit” shall consist of one share of Company common stock, par value $0.001 per share (“ Share ”), and a warrant to purchase one share of Company common stock at $0.46 per share (“ Warrant ”). The Shares, Warrants, and Units offered hereby, and the underlying shares of Common Stock, are sometimes referred to herein as the “ Securities ”. The Purchasers of the Units shall have the benefit of certain registration rights in respect of the Shares (including Shares underlying the Warrants or “Warrant Shares”) on the terms and conditions of a Registration Rights Agreement, in the form of Exhibit B hereto (the “ Registration Rights Agreement ”). The Company is offering Units (the “ Offering ”) for sale only to individuals, entities or groups, including, without limitation, corporations, limited liability companies, limited or general partnerships, joint ventures, associations, joint stock companies, trusts, unincorporated organizations, or governments or any agencies or political subdivisions thereof (each, a “ Person ”) who are “accredited investors” (as defined herein). All subscription proceeds will be paid upon subscription to the account or accounts of Richardson & Patel LLP, the escrow agent utilized by the Company for receipt of funds (the “ Escrow Agent ”).

          1.2 Subscription . Subject to the terms and conditions hereinafter set forth in this Agreement, each Purchaser hereby offers to purchase, at a price of $0.35 per share, the number of Units set forth beneath each such Purchaser’s name on the signature pages of this Agreement, for an aggregate purchase price (the “Purchase Price”) to be paid by such Purchaser in the amount set forth on the signature page beneath such Purchaser’s name, to such account or accounts as the Company may specify by written notice to the Purchaser.

          1.3 Subscription Procedures . To submit this Subscription, each Purchaser must deliver (i) this Agreement, including, without limitation, the annexed Purchaser Questionnaire, both duly completed and executed and (ii) an executed Registration Rights Agreement to the following address unless otherwise advised by the Company:

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          Each Purchaser shall, promptly following the delivery of the subscription documents as described above, deliver and pay the applicable purchase price in full for the Units being subscribed for by such Purchaser, in the amount of $0.35 for each Unit, in U.S. dollars, in immediately available funds, in accordance with the payment instructions attached hereto as Exhibit C . The Company may accept or reject subscriptions, in whole or in part in its sole discretion. The Company shall notify each Purchaser of the portion, if any, of such Purchaser’s subscription which has been accepted and, if any portion of a Purchaser’s subscription is rejected, shall cause the Escrow Agent to refund to such Purchaser the purchase price paid by the Purchaser for the shares of Units with respect to which such Purchaser’s subscription was rejected.

2. Closing .

          Upon acceptance of subscriptions for Units from a Purchaser, the Company may hold a closing of the purchase and sale of such Securities at any time after receipt of an aggregate amount of $800,000 of Units has been sold by the Company (the “ Initial Closing ”). The Company may thereafter hold one or more additional closings (each closing, including the Initial Closing, a “ Closing, ” and the final closing, the “ Final Closing ”) upon the purchase and sale of additional Securities until an aggregate amount of up to $1,700,000 (the “ Maximum Offering ”) of Units has been sold by the Company. The date of the Initial Closing will be referred to as the “Initial Closing Date” and the date of the Final Closing is referred to as the “Final Closing Date.” At the Closing with respect to the subscription by each Purchaser, to the extent the same is accepted by the Company, the Company will register in the name of each such Purchaser that number of Securities being purchased by such Purchaser in accordance with the information on the applicable signature page of this Agreement.

          2.1 Escrow . Pending each Closing, all funds paid in respect of this Agreement with regard to such Closing shall be deposited in an escrow account (the “ Escrow Account ”) maintained by the Escrow Agent pursuant to an Escrow Agreement among the Company, Purchaser and Escrow Agent, set forth as Exhibit D . The Escrow Account shall not be interest bearing. If the Company accepts subscriptions for the Securities at or prior to the Initial Closing Date or the Final Closing Date, as the case may be, then all subscription proceeds received for subscriptions accepted by the Company prior to such Closing Date shall be paid over to the Company at each Closing, net of any offering expenses, which shall be paid to the appropriate parties at each such Closing. If the Company shall not have received and accepted a Purchaser’s subscription or if the Offering is terminated and no Closing occurs, then that subscription shall be void and all funds paid hereunder by such Purchaser, without deduction therefrom or interest thereon, shall be promptly returned to such Purchaser. If the Offering is terminated and no Closing occurs, then all subscriptions shall be void and all funds paid hereunder by Purchasers, without deduction therefrom or interest thereon, shall be promptly returned to the Purchasers. The Offering shall automatically terminate, all subscriptions shall be void and all funds shall be refunded to the Purchasers as provided in this Section 2.1 (which refunds shall be made on or before March 31, 2008), unless on or before March 31, 2008 all of the conditions set forth in Section 3 hereof have been satisfied and the Initial Closing shall have occurred.

          2.2. Return of Funds . Each Purchaser hereby authorizes and directs the Escrow Agent to return or direct the return of any funds from the Escrow Account, without deduction therefrom or interest thereon, to the same account from which the funds were originally drawn, to the extent that such Purchaser’s subscription is not accepted prior to the termination of the Offering.

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3. Conditions to the Obligations of each Purchaser at Closing .

          The obligation of each Purchaser to purchase the Securities subscribed for by such Purchaser at the Closing is subject to the satisfaction on or prior to the Closing Date of the following conditions, each of which may be waived by the applicable Purchaser:

          3.1 Representations and Warranties . The representations and warranties of the Company contained in this Agreement which are qualified as to materiality must be true and correct in all respects and the representations and warranties of the Company contained in this Agreement which are not qualified as to materiality must be true and correct in all material respects as of the Closing Date except to the extent that the representations and warranties relate to an earlier date in which case the representations and warranties must be true and correct as written or true and correct in all material respects, as the case may be, as of the earlier date.

          3.2 Performance of Covenants . The Company shall have performed or complied in all material respects with all covenants and agreements required to be performed by it on or prior to the Closing pursuant to this Agreement.

          3.3 No Injunctions; etc . No court or governmental injunction, order or decree prohibiting the purchase and sale of the Units will be in effect. There will not be in effect any law, rule or regulation prohibiting or restricting the sale or requiring any consent or approval of any Person that has not been obtained to issue and sell the Units to the Purchasers.

          3.4 Closing Documents . At each Closing, the Company shall have delivered to the Escrow Agent the following:

          3.5 Waivers and Consents . The Company will have obtained all consents and waivers necessary to (i) execute and deliver this Agreement and all related documents and agreements, and (ii) to issue and deliver the Units, and all such consents and waivers will be in full force and effect.

4. Conditions to the Obligations of the Company at Closing .

          The obligation of the Company to issue and sell the Units to any Purchaser is subject to the satisfaction on or prior to each Closing Date of the following conditions, each of which may be waived by the Company:

          4.1 Receipt of Purchase Price . The Escrow Agent shall have received payment in full in immediately available funds in U.S. dollars of the Purchase Price for the Units with respect to which the Company has accepted the Subscription made by such Purchaser by means of this Agreement.

          4.2 Representations and Warranties . The representations and warranties of the Purchaser contained in this Agreement which are qualified as to materiality must be true and correct in all respects and the representations and warranties of the Purchaser contained in this Agreement which are not qualified as to materiality must be true and correct in all material respects as of the applicable Closing Date.

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          4.3 Performance of Covenants . The Purchaser will have performed or complied in all material respects with all covenants and agreements required to be performed by the Purchasers on or prior to the Closing pursuant to this Agreement.

          4.4 Purchaser Questionnaire . All of the information furnished by such Purchaser in the confidential purchaser questionnaire accompanying this Agreement (the “ Purchaser Questionnaire ”) shall have been accurate and complete in all material respects.

          4.5 No Injunctions . No court or governmental injunction, order or decree prohibiting the purchase or sale of the Units will be in effect.

          4.6 Closing Document . The Purchasers will have delivered to the Company the Registration Rights Agreement duly executed by the Purchasers.

5. Representations and Warranties of each Purchaser .

          Each Purchaser, in order to induce the Company to perform this Agreement, hereby represents and warrants, severally and not jointly, as follows:

          5.1 Due Authorization . Each Purchaser represents for such Purchaser to the Company that such Purchaser has full power and authority and has taken all action necessary to authorize such Purchaser to execute, deliver and perform such Purchaser’s obligations under this Agreement. This Agreement is the legal, valid and binding obligation of such Purchaser in accordance with its terms.

          5.2 Accredited Investor . Each Purchaser represents that such Purchaser is an Accredited Investor as that term is defined in Regulation D promulgated under the Securities Act of 1933, as amended (the “ Securities Act ”).

          5.3 No Investment Advice . The Company has not made any other representations or warranties to such Purchaser other than as set forth herein or incorporated herein by reference with respect to the Company or rendered any investment advice.

          5.4 Investment Experience . Each Purchaser represents that such Purchaser has not authorized any Person to act as a Purchaser Representative (as that term is defined in Regulation D of the General Rules and Regulations under the Securities Act) in connection with this transaction. Such Purchaser has such knowledge and experience in financial, investment and business matters that such Purchaser is capable of evaluating the merits and risks of the prospective investment in the securities of the Company. Such Purchaser has consulted with such independent legal counsel or other advisers as such Purchaser has deemed appropriate to assist such Purchaser in evaluating the proposed investment in the Company.

          5.5 Adequate Means . Each Purchaser represents as to such Purchaser that such Purchaser (i) has adequate means of providing for such Purchaser’s current financial needs and possible contingencies; and (ii) can afford (a) to hold unregistered securities for an indefinite period of time as required; and (b) sustain a complete loss of the entire amount of the subscription.

          5.6 Access to Information . Each Purchaser represents that such Purchaser has been afforded the opportunity to ask questions of, and receive answers from the officers and/or directors of the Company acting on its behalf concerning the terms and conditions of this transaction and to obtain any additional information, to the extent that the Company possesses such information or can acquire it without unreasonable effort or expense, necessary to verify the accuracy of the information furnished; and

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has had such opportunity to the extent such Purchaser considers it appropriate in order to permit such Purchaser to evaluate the merits and risks of an investment in the Company. It is understood that all documents, records and books pertaining to this investment have been made available for inspection, and that the books and records of the Company will be available upon reasonable notice for inspection by investors during reasonable business hours at its principal place of business. The foregoing shall in no way be deemed to limit the ability of each Purchaser to rely on the representations and warranties set forth herein or incorporated herein by reference.

          5.7 No Endorsement . Each Purchaser further acknowledges that the offer and sale of the Securities has not been passed upon or the merits thereof endorsed or approved by any state or federal authorities.

          5.8 Non-Registered Securities . Each Purchaser acknowledges that the offer and sale of the Securities have not been registered under the Securities Act or any state securities laws and the Securities and the underlying shares of Common Stock may be resold only if registered pursuant to the provisions thereunder or if an exemption from registration is available. Each Purchaser understands that the offer and sale of the Securities is intended to be exempt from registration under the Securities Act, based, in part, upon the representations, warranties and agreements of such Purchaser contained in this Agreement.

          5.9 No Resale . Each Purchaser represents that the Units being subscribed for, and the securities underlying the subscription, are being acquired solely for the account of such Purchaser for such Purchaser’s investment and not with a view to, or for resale in connection with, any distribution in any jurisdiction where such sale or distribution would be precluded. By such representation, such Purchaser means that no other Person has a beneficial interest in the Units or the Common Stock underlying such Units, and that no other Person has furnished or will furnish directly or indirectly, any part of or guarantee the payment of any part of the consideration to be paid by such Purchaser to the Company in connection therewith. Such Purchaser does not intend to dispose of all or any part of the Units or the Common Stock underlying such Units except in compliance with the provisions of the Securities Act and applicable state securities laws, and understands that the Units and the Common Stock underlying the Units are being offered pursuant to a specific exemption under the provisions of the Securities Act, which exemption(s) depends, among other things, upon the compliance with the provisions of the Securities Act.

          5.10 ERISA-based Investment . If Purchaser is acquiring the Units through a qualified pension, profit-sharing, stock bonus, Keogh or 401(k) plan or other pension or retirement plan qualified under Section 401(a) of the Internal Revenue Code of 1986, as amended (the “Code”), (such plans are referred to collectively as “Qualified Plans”) then Purchaser represents that the Qualified Plan (i) provides for a segregated account for the investor-beneficiary and (ii) gives the investor-beneficiary the power to direct each plan investment to the extent of the investor’s voluntary contributions plus the investor’s share of vested employer contributions. In addition, Purchaser represents that (a) the Purchaser is aware of certain federal income tax considerations applicable to Qualified Plans and IRAs, and (b) the Purchaser has determined that an investment in Preferred Shares is not a prohibited transaction under the Employee Retirement Income Security Act of 1974, as amended (“ERISA”), or the Code and has taken into account the requirements of prudence, diversification and any other applicable responsibilities imputed under ERISA or elsewhere.

          5.11 Legend . Each Purchaser hereby acknowledges and agrees that the Company may insert the following or similar legend on the face of the certificates evidencing the Securities purchased by such Purchaser and the Warrant Shares issued upon the exercise thereof, as the case may be, if required in compliance with the Securities Act or state securities laws:

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          5.12 Broker’s or Finder’s Commissions . No finder, broker, agent, financial person or other intermediary has acted on behalf of any Purchaser in connection with the sale of the Units by the Company or the consummation of this Agreement or any of the transactions contemplated hereby.

          Each Purchaser certifies that each of the foregoing representations and warranties by such Purchaser set forth in this Section 5 is true as of the date hereof and shall survive such date.

6. Representations and Warranties of the Company .

          The Company represents and warrants to the Purchasers as follows as of the Closing, each such representation and warranty being made subject to such disclosures as are made pursuant to this Agreement or any schedule or exhibit delivered in connection herewith at the Closing:

          6.1 Organization, Good Standing and Qualification . The Company is a corporation duly organized, validly existing and in good standing under the laws of the State of Minnesota. The Company has full corporate power and authority to own and hold its properties and to conduct its business. The Company is duly licensed or qualified to do business, and in good standing, in each jurisdiction in which the nature of its business requires licensing, qualification or good standing, except for any failure to be so licensed or qualified or in good standing that would not have a material adverse effect on the Company or its results of operations, assets and financial condition, taken as a whole, or on its ability to perform its obligations under this Agreement or to issue the Units (a “ Material Adverse Effect ”).

          6.2 Capitalization . As of the Initial Closing, the authorized capital stock of the Company will consist of 20,000,000 shares of Common Stock, a par value of $0.001 per share. Immediately prior to the Initial Closing, approximately 1,096,829 shares of Common Stock will be issued and outstanding. As of the Initial Closing, all the outstanding shares of Common Stock will have been duly authorized and validly issued and will be fully paid and nonassessable and free of preemptive rights created by or through the Company, and will have been issued in compliance with all federal and state securities laws, and will not have been issued in violation of any preemptive rights or similar rights to subscribe for or purchase securities. Other than as described in the Company’s Offering Memorandum dated on or about January 31, 2008 (the “Memorandum”), there are no options, warrants or other rights, convertible debt, agreements, arrangements or commitments of any character obligating the Company to issue or sell any shares of capital stock of or other equity interests in the Company. The Company is not obligated to retire, redeem, repurchase or otherwise reacquire any of its capital stock or other securities. There are no stockholders agreements, voting agreements or other similar agreements with respect to the Common Stock to which the Company is a party. Except as disclosed in or pursuant to this Agreement, the Company does not directly or indirectly own or have any investment in any of the capital stock of, or any other proprietary interest in, any Person. The Company has not adopted a stockholders rights plan, poison pill or similar arrangement.

          6.3 Corporate Power, Authorization; Enforceability . The Company has full corporate power and authority to execute, deliver and enter into this Agreement, the Charter Amendment, the Escrow Agreement and the Registration Rights Agreement (collectively, the “ Transaction Documents ”) and to

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consummate the transactions contemplated hereby and thereby. Except as contemplated by this Agreement, including the next two succeeding sentences, all action on the part of the Company, its directors or stockholders necessary for the authorization, execution, delivery and performance of the Transaction Documents by the Company, the authorization, sale, issuance and delivery of the Units contemplated hereby and the performance of the Company’s obligations hereunder and thereunder has been taken. The Units to be purchased on the Closing Date and the shares of Common Stock issuable upon the exercise of the Warrants have been duly authorized and, when issued in accordance with this Agreement, will be validly issued, fully paid and nonassessable and will be free and clear of any mortgage, deed of trust, pledge, hypothecation, assignment, encumbrance, lien (statutory or other) or preference, priority, right or other security interest or preferential arrangement of any kind or nature whatsoever (collectively, “ Liens ”) imposed by or through the Company other than restrictions imposed by this Agreement and the Registration Rights Agreeme