MASTER SECURITY AGREEMENT dated as of December 29, 2006 (Agreement)

Exhibit 4.6

MASTER SECURITY AGREEMENT

dated as of December 29, 2006 (“Agreement”)

THIS AGREEMENT is between General Electric Capital Corporation (together with its successors and assigns, if any, “Secured Party”) and Precision Therapeutics, Inc. (“Debtor”). Secured Party has an office at 83 Wooster Heights Road, Danbury, CT 06810. Debtor is a corporation organized and existing under the laws of the state of Delaware (“the State”). Debtor’s mailing address and chief place of business is 2516 Jane Street, Pittsburgh, Allegheny County, PA 15203.

Debtor grants to Secured Party, its successors and assigns, a security interest in and against all property listed on any collateral schedule now or in the future annexed to or made a part of this Agreement (“Collateral Schedule”), and in and against all additions, attachments, accessories and accessions to such property, all substitutions, replacements or exchanges therefor, and all insurance and/or other proceeds thereof (all such property is individually and collectively called the “Collateral”). This security interest is given to secure the payment and performance of all debts, obligations and liabilities of any kind whatsoever of Debtor to Secured Party, now existing or arising in the future, including but not limited to the payment and performance of certain Promissory Notes from time to time identified on any Collateral Schedule (collectively “Notes” and each a “Note”), and any renewals, extensions and modifications of such debts, obligations and liabilities (such Notes, debts, obligations and liabilities are called the “Indebtedness”).

Debtor represents, warrants and covenants as of the date of this Agreement and as of the date of each Collateral Schedule that:

(a) Debtor’s exact legal name is as set forth in the preamble of this Agreement and Debtor is, and will remain, duly organized, existing and in good standing under the laws of the State set forth in the preamble of this Agreement, has its chief executive offices at the location specified in the preamble, and is, and will remain, duly qualified and licensed in every jurisdiction wherever necessary to carry on its business and operations;

(b) Debtor has adequate power and capacity to enter into, and to perform its obligations under this Agreement, each Note and any other documents evidencing, or given in connection with, any of the Indebtedness (all of the foregoing are called the “Debt Documents”);

(c) This Agreement and the other Debt Documents have been duly authorized, executed and delivered by Debtor and constitute legal, valid and binding agreements enforceable in accordance with their terms, except to the extent that the enforcement of remedies may be limited under applicable bankruptcy and insolvency laws;

(d) No approval, consent or withholding of objections is required from any governmental authority or instrumentality with respect to the entry into, or performance by Debtor of any of the Debt Documents, except any already obtained;

(e) The entry into, and performance by, Debtor of the Debt Documents will not (i) violate any of the organizational documents of Debtor or any judgment, order, law or regulation applicable to Debtor, or (ii) result in any breach of or constitute a default under any contract to which Debtor is a party, or result in the creation of any lien, claim or encumbrance on any of Debtor’s property (except for liens in favor of Secured Party) pursuant to any indenture, mortgage, deed of trust, bank loan, credit agreement, or other material agreement or instrument to which Debtor is a party;

(f) There are no suits or proceedings pending in court or before any commission, board or other administrative agency against or affecting Debtor which could, in the aggregate, have a material adverse effect on Debtor, its business or operations, or its ability to perform its obligations under the Debt Documents, nor does Debtor have reason to believe that any such suits or proceedings are threatened;

(g) All financial statements delivered to Secured Party in connection with the Indebtedness have been prepared in accordance with generally accepted accounting principles, and since the date of the most recent financial statement, there has been no material adverse change in Debtors financial condition;

(h) The Collateral is not, and will not be, used by Debtor for personal, family or household purposes;

(i) The Collateral is, and will remain, in good condition and repair, ordinary wear and tear excepted and Debtor will not be negligent in its care and use;

(j) Debtor is, and will remain, the sole and lawful owner, and in possession of, the Collateral, and has the sole right and lawful authority to grant the security interest described in this Agreement;

(k) The Collateral is, and will remain, free and clear of all liens, claims and encumbrances of any kind whatsoever, except for (i) liens in favor of Secured Party, (ii) liens for taxes not yet due or for taxes being contested in good faith and which do not involve, in the judgment of Secured Party, any risk of the sale, forfeiture or loss of any of the Collateral and with respect to which adequate

reserves have been set aside for the payment thereof in accordance with GAAP, and (iii) inchoate materialmen’s, mechanic’s, repairmen’s and similar liens arising by operation of law in the normal course of business for amounts which are not delinquent; (iv) liens set forth on Schedule 2(k); (v) Liens not to exceed $250,000 in the aggregate in any fiscal year (A) upon or in any equipment acquired or held by Debtor to secure the purchase price of such equipment (or other equipment secured by the same creditor) or additional Debt incurred solely for the purpose of financing the acquisition or lease of such equipment, or (B) existing on such equipment at the time of its acquisition provided that the Lien is confined solely to the equipment so acquired and improvements thereon (and other equipment to which such creditor has a security interest) and the proceeds of such equipment; and (vi) the sale, license or other disposition of any of Debtor’s assets in the ordinary course of business (all of such liens are called “Permitted Liens”);

(l) Debtor is and will remain in full compliance with all laws and regulations applicable to it including, without limitation, (i) ensuring that no person who owns a controlling interest in or otherwise controls Debtor is or shall be (Y) listed on the Specially Designated Nationals and Blocked Person List maintained by the Office of Foreign Assets Control (“OFAC”), Department of the Treasury, and/or any other similar lists maintained by OFAC pursuant to any authorizing statute, Executive Order or regulation or (Z) a person designated under Section 1(b), (c) or (d) of Executive Order No. 13224 (September 23, 2001), any related enabling legislation or any other similar Executive Orders, and (ii) compliance with all applicable Bank Secrecy Act (“BSA”) laws, regulations and government guidance on BSA compliance and on the prevention and detection of money laundering violations;

(m) Debtor’s Intellectual Property, as defined in Section 7 below, is and will remain free and clear of all liens, claims and encumbrances of any kind whatsoever, except for Permitted Liens as defined in subsection (k) of this Section;

(n) Debtor has not and will not enter into any other agreement or financing arrangement in which it granted a negative pledge in Debtor’s Intellectual Property to any other party;

(o) Debtor agrees that it shall not, and shall not allow any of its subsidiaries to, directly or indirectly, create, incur, assume, permit to exist, guarantee or otherwise become or remain directly or indirectly liable with respect to, any Debt (as hereinafter defined), except for (i) Debt of Debtor to Secured Party, (ii) Debt existing on the date hereof and set forth on Schedule A to this Agreement, and (iii) Debt not to exceed $250,000 in the aggregate in any fiscal year of Debtor secured by liens described in clause (v) of the definition of Permitted Liens and provided such Debt does not exceed the lesser of cost or fair market value of the equipment financed with such Debt; and (iv) unsecured Debt in an aggregate amount not to exceed $100,000 that is subordinated to the Indebtedness on terms and conditions acceptable to Secured Party in its reasonable discretion (“Subordinated Debt”). The term “Debt” shall mean, with respect to any person, at any date, without duplication, (a) all obligations of such person for borrowed money, (b) all obligations of such person evidenced by bonds, debentures, notes or other similar instruments, or upon which interest payments are customarily made, (c) all obligations of such person to pay the deferred purchase price of property or services incurred in the ordinary course of business if the purchase price is due more than six (6) months from the date the obligation is incurred, (d) all capital lease obligations of such person, (e) the principal balance outstanding under any synthetic lease, tax retention operating lease, off-balance sheet loan or similar off-balance sheet financing product, (f) all obligations of such person to purchase securities (or other property) which arise out of or in connection with the issuance or sale of the same or substantially similar securities (or property), (g) all contingent or non-contingent obligations of such person to reimburse any bank or other person in respect of amounts paid under a letter of credit or similar instrument, (h) all Indebtedness secured by a lien on any asset of such person, whether or not such Debt is otherwise an obligation of such person, (i) all obligations of such person under any foreign exchange contract, currency swap agreement; interest rate swap, cap or collar agreement or other similar agreement or arrangement designed to alter the risks of that person arising from fluctuations in currency values or interest rates, in each case whether contingent or matured, and (j) all obligations or liabilities of other guaranteed by such person; and (m) all obligations of such person to trade creditors incurred in the ordinary course of business and more than one hundred twenty (120) days past due;

(p) Debtor agrees that it shall not, and shall not allow any of its subsidiaries to, (i) make any payment in respect of any Subordinated Debt, except in accordance with the subordination terms thereof or (ii) amend, supplement, modify or waive any of the terms of any document governing any Subordinated Debt; and

(q) Debtor (i) shall, within 30 days after the initial funding of the Indebtedness secured hereby, cause each securities, depository or disbursement account of Debtor or any of its subsidiaries (other than any tax or payroll account) to be subject to a control agreement satisfactory to Secured Party in its reasonable discretion and (ii) shall not and shall not allow any of its subsidiaries to open or maintain any securities, depository or disbursement accounts except upon thirty (30) days’ prior written notice to Secured Party and Debtor shall not, and shall not allow any Subsidiary to, use any such accounts until such time as the applicable securities intermediary or depository institution, as the case may be, Debtor or such Subsidiary of Debtor, as the case may be, and Secured Party have entered into a control agreement satisfactory to Secured Party and in any event sufficient to perfect a first priority lien and security interest in such account in favor of Secured Party. In the event Secured Party chooses not to request a control agreement over each securities, depository, or disbursement account of Debtor or any of its subsidiaries, Debtor agrees that such account or accounts in aggregate shall not and shall not be allowed to contain individually or in aggregate more than four million dollars ($4,000,000) and that Debtor’s account(s) subject to a control agreement shall contain all of Debtor’s remaining deposits and securities.

(a) Until the declaration of any default, Debtor shall remain in possession of the Collateral, including the collateral covered by any control agreement described in section 2(q) above; except that Secured Party shall have the right to possess (i) any chattel paper or instrument that constitutes a part of the Collateral, and (ii) any other Collateral in which Secured Party’s security interest may be perfected only by possession. Secured Party may inspect any of the Collateral during normal business hours after giving Debtor reasonable prior notice. If Secured Party asks, Debtor will promptly notify Secured Party in writing of the location of any Collateral.

(b) Debtor shall (i) use the Collateral only in its trade or business, (ii) maintain all of the Collateral in good operating order and repair, normal wear and tear excepted, (iii) use and maintain the Collateral only in compliance with manufacturers recommendations and all applicable laws, and (iv) keep all of the Collateral free and clear of all liens, claims and encumbrances (except for Permitted Liens).

(c) Secured Party does not authorize and Debtor agrees it shall not (i) part with possession of any of the Collateral (except to Secured Party or for maintenance and repair), (ii) remove any of the Collateral from the continental United States, or (iii) sell, rent, lease, mortgage, license, grant a security interest in or otherwise transfer or encumber (except for Permitted Liens) any of the Collateral except in the ordinary course of business.

(d) Debtor shall pay promptly when due all taxes, license fees, assessments and public and private charges levied or assessed on any of the Collateral, on its use, or on this Agreement or any of the other Debt Documents. At its option, Secured Party may discharge taxes, liens, security interests or other encumbrances at any time levied or placed on the Collateral and may pay for the maintenance, insurance and preservation of the Collateral and effect compliance with the terms of this Agreement or any of the other Debt Documents. Debtor agrees to reimburse Secured Party, on demand, all costs and expenses incurred by Secured Party in connection with such payment or performance and agrees that such reimbursement obligation shall constitute Indebtedness.

(e) Debtor shall, at all times, keep accurate and complete records of the Collateral, and Secured Party shall have the right to inspect and make copies of all of Debtor’s books and records relating to the Collateral during normal business hours, after giving Debtor reasonable prior notice.

(f) Debtor agrees and acknowledges that any third person who may at any time possess all or any portion of the Collateral shall be deemed to hold, and shall hold, the Collateral as the agent of, and as pledge holder for, Secured Party. Secured Party may at any time give notice to any third person described in the preceding sentence that such third person is holding the Collateral as the agent of, and as pledge holder for, the Secured Party.

(a) Debtor shall at all times bear the entire risk of any loss, theft, damage to, or destruction of, any of the Collateral from any cause whatsoever.

(b) Debtor agrees to keep the Collateral insured against loss or damage by fire and extended coverage perils, theft, burglary, and for any or all Collateral which are vehicles, for risk of loss by collision, and if requested by Secured Party, against such other risks as Secured Party may reasonably require. The insurance coverage shall be in an amount no less than the full replacement value of the Collateral, and deductible amounts, insurers and policies shall be acceptable to Secured Party. Debtor shall deliver to Secured Party policies or certificates of insurance evidencing such coverage. Each policy shall name Secured Party as additional insured and lender’s loss payee, shall provide for coverage to Secured Party regardless of the breach by Debtor of any warranty or representation made therein, shall not be subject to co-insurance, and shall provide that coverage may not be canceled or altered by the insurer except upon thirty (30) days prior written notice to Secured Party. Debtor appoints Secured Party as its attorney-in-fact to make proof of loss, claim for insurance and adjustments with insurers, and to receive payment of and execute or endorse all documents, checks or drafts in connection with insurance payments. Secured Party shall not act as Debtor’s attorney-in-fact unless Debtor is in default. Proceeds of insurance shall be applied, at the option of Secured Party, to repair or replace the Collateral or to reduce any of the Indebtedness.

(a) Debtor shall promptly notify Secured Party of (i) any change in the name of Debtor, (ii) any change in the state of its incorporation, organization or registration, (iii) any relocation of its chief executive offices, (iv) any relocation of any of the Collateral, (v) any of the Collateral being lost, stolen, missing, destroyed, materially damaged or worn out, or (vi) any lien, claim or encumbrance other than Permitted Liens attaching to or being made against any of the Collateral.

(b) Debtor will deliver to Secured Party financial statements as follows. If Debtor is a privately held company, then Debtor agrees to provide monthly financial statements, certified by Debtor’s president or chief financial officer including a balance sheet, statement of operations and cash flow statement within 45 days of the end of each fiscal quarter and its complete audited annual financial statements, certified by a recognized firm of certified public accountants, within 180 days of fiscal year end or at such time as Debtor’s Board of Directors receives the audit. If Debtor is a publicly held company, then Debtor agrees to provide quarterly unaudited statements and annual audited statements, certified by a recognized firm of certified public accountants, within 10 days after the statements are provided to the Securities and Exchange Commission (“SEC”). All such statements are to be prepared using generally accepted accounting principles (“GAAP”) and, if Debtor is a publicly held company, are to be in compliance with SEC requirements.

(a) Debtor shall, upon request of Secured Party, furnish to Secured Party such further information, execute and deliver to Secured Party such documents and instruments (including, without limitation, Uniform Commercial Code financing statements) and shall do such other acts and things as Secured Party may at any time reasonably request relating to the perfection or protection of the security interest created by this Agreement or for the purpose of carrying out the intent of this Agreement. Without limiting the foregoing, Debtor shall cooperate and do all acts deemed necessary or advisable by Secured Party to continue in Secured Party a perfected first security interest in the Collateral, and shall obtain and furnish to Secured Party any subordinations, releases, landlord waivers, lessor waivers, mortgagee waivers, or control agreements, and similar documents as may be from time to time requested by, and in form and substance satisfactory to, Secured Party.

(b) Debtor authorizes Secured Party to file a financing statement and amendments thereto describing the Collateral and containing any other information required by the applicable Uniform Commercial Code. Debtor irrevocably grants to Secured Party the power to sign Debtor’s name and generally to act on behalf of Debtor to execute and file applications for title, transfers of title, financing statements, notices of lien and other documents pertaining to any or all of the Collateral; this power is coupled with Secured Party’s interest in the Collateral. Debtor shall, if any certificate of title be required or permitted by law for any of the Collateral, obtain and promptly deliver to Secured Party such certificate showing the lien of this Agreement with respect to the Collateral. Debtor ratifies its prior authorization for Secured Party to file financing statements and amendments thereto describing the Collateral and containing any other information required by the Uniform Commercial Code if filed prior to the date hereof.

(c) Debtor shall indemnify and defend the Secured Party, its successors and assigns, and their respective directors, officers and employees, from and against all claims, actions and suits (including, without limitation, related attorneys’ fees) of any kind whatsoever arising, directly or indirectly, in connection with any of the Collateral.

(a) Debtor shall be in default under this Agreement and each of the other Debt Documents if:

(i) Debtor breaches its obligation to pay when due any installment or other amount due or coming due under any of the Debt Documents and fails to cure the breach within ten (10) days;

(ii) Debtor, without the prior written consent of Secured Party, (A) attempts to or does sell, rent, lease, license, mortgage, grant a security interest in, or otherwise transfer or encumber (except for Permitted Liens) any of the Collateral; or (B) breaches any of its obligations under Section 2(o) or 2(p) and fails to cure the breach within ten (10) days;

(iii) Debtor breaches any of its insurance obligations under Section 4 and such breach is not cured within 7 days of its occurrence;

(iv) Debtor breaches any of its other obligations under any of the Debt Documents and fails to cure that breach within thirty (30) days after written notice from Secured Party;

(v) Any warranty, representation or statement made by Debtor in any of the Debt Documents or otherwise in connection with any of the Indebtedness shall be false or misleading in any material respect;

(vi) Any of the Collateral is subjected to attachment, execution, levy, seizure or confiscation in any legal proceeding or otherwise, or if any legal or administrative proceeding is commenced against Debtor or any of the Collateral, which in the good faith judgment of Secured Party subjects any of the Collateral to a material risk of attachment, execution, levy, seizure or confiscation and no bond is posted or protective order obtained to negate such risk;

(vii) Debtor or any guarantor or other obligor for any of the Indebtedness (collectively “Guarantor”) dissolves, terminates its existence, becomes insolvent or ceases to do business as a going concern;

(viii) If Debtor or any Guarantor is a natural person, Debtor or any such Guarantor dies or becomes incompetent;

(ix) A receiver is appointed for all or of any part of the property of Debtor or any Guarantor, or Debtor or any Guarantor makes any assignment for the benefit of creditors;

(x) Debtor or any Guarantor files a petition under any bankruptcy, insolvency or similar law, or any such petition is filed against Debtor or any Guarantor and is not dismissed within forty-five (45) days;

(xi) Debtor’s improper filing of an amendment or termination statement relating to a filed financing statement describing the Collateral;

(xii) There is a material adverse change in the Debtor’s financial condition as determined in good faith by Secured Party;

(xiii) Any Guarantor revokes or attempts to revoke its guaranty of any of the Indebtedness or fails to observe or perform any material covenant, condition or agreement to be performed under any guaranty or other related document to which it is a party; or

(xiv) Debtor defaults under any other material obligation for (A) borrowed money, (B) the deferred purchase price of property or (C) payments due under any lease agreement and such default is not cured within ten (10) days of Debtor receiving notice of such default;

(xv) At any time during the term of this Agreement less than 25% of Debtor’s voting capital stock, or effective control of Debtor’s voting capital stock, issued and outstanding from time to time, is held by the holders of such stock on the date of this Agreement (other than due to the sale of Debtor’s equity securities in a public offering or to venture capital investors) or Debtor sells all or substantially all of its assets, in each case without Secured Party’s prior written consent; or

(xvi) Debtor or any guarantor or other obligor for any of the Indebtedness sells, licenses, sublicenses, transfers, assigns, mortgages, pledges, leases, grants a security interest in or encumbers any or all of Debtor’s Intellectual Property now existing or hereafter acquired, except for permitted liens or as otherwise set forth below. Intellectual Property shall consist of but not be limited to any and all owned or licensed patents, trademarks and copyrights. For purposes of this paragraph xvi, licenses or sublicenses by the Debtor of its Intellectual Property as part of a research and development or licenses or sublicenses granted by Debtor of its Intellectual Property in the ordinary course of Debtor’s business or similar arrangements permitted by this Agreement shall be excluded. Debtor shall provide Secured Party with a listing of licenses and sublicenses granted to third parties within ten (10) days of receipt of written request.

(b) If Debtor is in default, the Secured Party, at its option, may declare any or all of the Indebtedness to be immediately due and payable, without demand or notice to Debtor or any Guarantor. The accelerated obligations and liabilities shall bear interest (both before and after any judgment) until paid in full at the lower of eighteen percent (18%) per annum or the maximum rate not prohibited by applicable law.

(c) After default, Secured Party shall have all of the rights and remedies of a Secured Party under the Uniform Commercial Code, and under any other applicable law. Without limiting the foregoing, Secured Party shall have the right to (i) notify any account debtor of Debtor or any obligor on any instrument which constitutes part of the Collateral to make payment to the Secured Party, (ii) with or without legal process, enter any premises where the Collateral may be and take possession of and remove the Collateral from the premises or store it on the premises, (iii) sell the Collateral at public or private sale, in whole or in part, and have the right to bid and purchase at said sale, or (iv) lease or otherwise dispose of all or part of the Collateral, applying proceeds from such disposition to the obligations then in default. If requested by Secured Party, Debtor shall promptly assemble the Collateral and make it available to Secured Party at a place to be designated by Secured Party which is reasonably convenient to both parties. Secured Party may also render any or all of the Collateral unusable at the Debtor’s premises and may dispose of such Collateral on such premises without liability for rent or costs. Any notice that Secured Party is required to give to Debtor under the Uniform Commercial Code of the time and place of any public sale or the time after which any private sale or other intended disposition of the Collateral is to be made shall be deemed to constitute reasonable notice if such notice is given to the last known address of Debtor at least five (5) days prior to such action. As a clarification, Secured Party may not exercise any rights under the control agreements described in Section 2(q) unless a default has occurred and is continuing.

(d) Proceeds from any sale or lease or other disposition shall be applied: first, to all costs of repossession, storage, and disposition including without limitation attorneys, appraisers’, and auctioneers’ fees; second, to discharge the obligations then in default, third, to discharge any other Indebtedness of Debtor to Secured Party, whether as obligor, endorser, guarantor, surety or indemnitor; fourth, to expenses incurred in paying or settling liens and claims against the Collateral; and lastly, to Debtor, if there exists any surplus. Debtor shall remain fully liable for any deficiency.

(e) Debtor agrees to pay all reasonable attorneys’ fees and other fees, costs and expenses incurred by Secured Party (including, without limitation, the allocated cost of in-house legal counsel) in connection with the enforcement, assertion, defense or preservation of Secured Party’s rights and remedies under this Agreement, or if prohibited by law, such lesser sum as may be permitted. Debtor further agrees that such fees and costs shall constitute Indebtedness.

(f) Secured Party’s rights and remedies under this Agreement or otherwise arising are cumulative and may be exercised singularly or concurrently. Neither the failure nor any delay on the part of the Secured Party to exercise any right, power or privilege under this Agreement shall operate as a waiver, nor shall any single or partial exercise of any right. power or privilege preclude any other or further exercise of that or any other right, power or privilege. SECURED PARTY SHALL NOT BE DEEMED TO HAVE WAIVED ANY OF ITS RIGHTS UNDER THIS AGREEMENT OR UNDER ANY OTHER AGREEMENT, INSTRUMENT OR PAPER SIGNED BY DEBTOR UNLESS SUCH WAIVER IS EXPRESSED IN WRITING AND SIGNED BY SECURED PARTY. A waiver on any one occasion shall not be construed as a bar to or waiver of any right or remedy on any future occasion.

(g) DEBTOR AND SECURED PARTY UNCONDITIONALLY WAIVE THEIR RIGHTS TO A JURY TRIAL OF ANY CLAIM OR CAUSE OF ACTION BASED UPON OR ARISING OUT OF THIS AGREEMENT, ANY OF THE OTHER DEBT DOCUMENTS, ANY OF THE INDEBTEDNESS SECURED HEREBY, ANY DEALINGS BETWEEN DEBTOR AND SECURED PARTY RELATING TO THE SUBJECT MATTER OF THIS TRANSACTION OR ANY RELATED TRANSACTIONS, AND/OR THE RELATIONSHIP THAT IS BEING ESTABLISHED BETWEEN DEBTOR AND SECURED PARTY. THE SCOPE OF THIS WAIVER IS INTENDED TO BE ALL ENCOMPASSING OF ANY AND ALL DISPUTES THAT MAY BE FILED IN ANY COURT. THIS WAIVER IS IRREVOCABLE. THIS WAIVER MAY NOT BE MODIFIED EITHER ORALLY OR IN WRITING. THE WAIVER ALSO SHALL APPLY TO ANY SUBSEQUENT AMENDMENTS, RENEWALS, SUPPLEMENTS OR MODIFICATIONS TO THIS AGREEMENT, ANY OTHER DEBT DOCUMENTS, OR TO ANY OTHER DOCUMENTS OR AGREEMENTS RELATING TO THIS TRANSACTION OR ANY RELATED TRANSACTION. THIS AGREEMENT MAY BE FILED AS A WRITTEN CONSENT TO A TRIAL BY THE COURT.

(a) This Agreement, any Note and/or any of the other Debt Documents may be assigned, in whole or in part, by Secured Party without notice to Debtor, and Debtor agrees not to assert against any such assignee, or assignee’s assigns, any defense, set-off, recoupment claim or counterclaim which Debtor has or may at any time have against Secured Party for any reason whatsoever. Debtor agrees that if Debtor receives written notice of an assignment from Secured Party, Debtor will pay all amounts payable under any assigned Debt Documents to such assignee or as instructed by Secured Party. Debtor also agrees to confirm in writing receipt of the notice of assignment as may be reasonably requested by Secured Party or assignee.

(b) All notices to be given in connection with this Agreement shall be in writing, shall be addressed to the parties at their respective addresses set forth in this Agreement (unless and until a different address may be specified in a written notice to the other party), and shall be deemed given (i) on the date of receipt if delivered in hand or by facsimile transmission, (ii) on the next business day after being sent by express mail, and (iii) on the fourth business day after being sent by regular, registered or certified mail. As used herein, the term ‘business day” shall mean and include any day other than Saturdays, Sundays, or other days on which commercial banks in New York, New York are required or authorized to be closed.

(c) Debtor agrees to pay all reasonable attorneys’ fees and all other fees, costs and expenses incurred by Secured Party (including, without limitation, the allocated cost of in-house legal counsel) in connection with the preparation, negotiation and closing of the transactions contemplated in this Agreement and all related documents and schedules and in connection with the continued administration thereof, including, without limitation, any amendments, modifications, consents or waivers thereof and in connection with the protection, monitoring or preservation of the Collateral. Debtor further agrees that such fees and costs shall constitute Indebtedness.

(d) Secured Party may correct patent errors and fill in all blanks in this Agreement or in any Collateral Schedule consistent with the agreement of the parties.

(e) Time is of the essence of this Agreement. This Agreement shall be binding, jointly and severally, upon all parties described as the “Debtor” and their respective heirs, executors, representatives, successors and assigns, and shall inure to the benefit of Secured Party, its successors and assigns.

(f) This Agreement and its Collateral Schedules constitute the entire agreement between the parties with respect to the subject matter of this Agreement and supersede all prior understandings (whether written, verbal or implied) with respect to such subject matter. THIS AGREEMENT AND ITS COLLATERAL SCHEDULES SHALL NOT BE CHANGED OR TERMINATED ORALLY OR BY COURSE OF CONDUCT, BUT ONLY BY A WRITING SIGNED BY BOTH PARTIES. Section headings contained in this Agreement have been included for convenience only, and shall not affect the construction or interpretation of this Agreement.

(g) This Agreement shall continue in full force and effect until all of the Indebtedness has been indefeasibly paid in full to Secured Party or its assignee. The surrender, upon payment or otherwise, of any Note or any of the other documents evidencing any of the Indebtedness shall not affect the right of Secured Party to retain the Collateral for such other Indebtedness as may then exist or as it may be reasonably contemplated will exist in the future. This Agreement shall automatically be reinstated if Secured Party is ever required to return or restore the payment of all or any portion of the Indebtedness (all as though such payment had never been made).

(h) Debtor authorizes Secured Party to use its name, logo and/or trademark without notice to or consent by Debtor, in connection with certain promotional materials that Secured Party may disseminate to the public. The promotional materials may include, but are not limited to, brochures, video tape, internet website, press releases, advertising in newspaper and/or other periodicals, lucites, and any other materials relating the fact that Secured Party has a financing relationship with Debtor and such materials may be developed, disseminated and used without Debtor’s review. Nothing herein obligates Secured Party to use Debtor’s name, logo and/or trademark, in any promotional materials of Secured Party.

(i) THIS AGREEMENT AND THE RIGHTS AND OBLIGATIONS OF THE PARTIES HEREUNDER SHALL IN ALL RESPECTS BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH, THE INTERNAL LAWS OF THE STATE OF CONNECTICUT (WITHOUT REGARD TO THE CONFLICT OF LAWS PRINCIPLES OF SUCH STATE), INCLUDING ALL MATTERS OF CONSTRUCTION, VALIDITY AND PERFORMANCE, REGARDLESS OF THE LOCATION OF THE COLLATERAL.

IN WITNESS WHEREOF, Debtor and Secured Party, intending to be legally bound hereby, have duly executed this Agreement in one or more counterparts, each of which shall be deemed to be an original, as of the day and year first aforesaid.

COLLATERAL SCHEDULE NO. 001

Part of Master Security Agreement dated as of December 29, 2006 as amended, restated, supplemented or otherwise modified from time to time (the “Contract”) between GENERAL ELECTRIC CAPITAL CORPORATION (the “Secured Party”) and PRECISION THERAPEUTICS, INC. (the “Debtor”).

As security for the full and faithful payment of all Indebtedness (as defined in the Contract) owing by Debtor to Secured party and performance by the Debtor of all of the terms and conditions upon the Debtor’s part to be performed under the Contract and any other obligation of the Debtor to the Secured Party now or hereafter in existence, the Debtor does hereby grant to the Secured Party a security interest in the property listed below (all hereinafter collectively called the “Collateral”):

All of the Debtor’s personal property of every kind and nature, including, without limitation, all accounts, chattel paper, commercial tort claims, deposit accounts, documents, goods, equipment, fixtures, instruments, investment property, inventory, letter-of-credit rights, letters of credit, supporting obligations, any other contract rights or rights to the payment of money, and general intangibles (excluding all of Debtor’s Intellectual Property (as hereafter defined), whether now owned or hereafter arising or acquired by the Debtor, together with all accessions and additions thereto, proceeds and products thereof (including, without limitation, any proceeds resulting under insurance policies), and substitutions and replacements therefor (with each of the foregoing terms that are defined in the UCC having the meaning set forth in the UCC). The Collateral shall not include any of Debtor’s intellectual property, which shall be defined as any and all copyright, trademark, servicemark, patent, design right, software, license, trade secret and intangible rights of Debtor and any applications, registrations, claims, licenses, products, proceeds, awards, judgments, amendments, renewals, extensions, improvements and insurance claims related thereto (collectively, “Intellectual Property”) now owned or hereafter acquired, or any claims for damages by way of any past, present or future infringement of any of the foregoing; provided however that the Collateral shall include all accounts and general intangibles that consist of rights of payment and proceeds from the sale, licensing or disposition of all or any part, or rights in, the foregoing (“Rights to Payment”). Notwithstanding the foregoing, if a judicial authority (including a U.S. Bankruptcy Court) holds that a security interest in the underlying Intellectual Property is necessary to have a security interest in the Rights to Payment, then the Collateral shall automatically, and effective as of the date hereof, include the Intellectual Property to the extent necessary to permit perfection of the Lender’s security interest in the Rights of Payment.

In the event of a default by the Debtor with respect to any of the conditions, terms, covenants and provisions under the Contract or other agreement, Secured Party shall have the rights and remedies provided under the Contract and/or of a secured party under the Uniform Commercial Code with respect to the Collateral. The Debtor shall have the same obligations with respect to the Collateral as it has under the Contract with respect to the Collateral financed.

This Agreement shall run to the benefit of the Secured Party’s successors and assigns.

Dated: December 29, 2006

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