AMENDMENT TO AMENDED AND RESTATED LOAN AND SECURITY AGREEMENT

(iii)                               When Borrower desires to obtain a Growth Capital Advance, Borrower shall notify Bank (which notice shall be irrevocable) by facsimile transmission to be received no later than 3:00 p.m. Pacific time three (3) Business Days before the day on which the Growth Capital Advance is to be made.  Such notice shall be substantially in the form of Exhibit B.

3.                                      Section 2.3(a)(ii) is amended in its entirety to read as follows:

(ii)                                  Growth Capital Advances.  Except as set forth in Section 2.3(b), the Growth Capital Advances shall bear interest, on the outstanding Daily Balance thereof, at a floating rate equal to 2.25% above the Prime Rate, provided however that at no time shall the rate be less than 5.50%

4.                                      The second paragraph in Section 6.3 is amended in its entirety to read as follows:

Within 30 days after the last day of each month, Borrower shall deliver to Bank a Borrowing Base Certificate signed by a Responsible Officer in substantially the form of Exhibit C hereto, together with aged listings of accounts receivable and accounts payable.

5.                                      Section 6.7 of the Agreement is amended in its entirety to read as follows:

6.7                                 Accounts.  Borrower shall maintain and shall cause each of its Subsidiaries to maintain its primary non-interest bearing operating account with Bank, and the cash balance of such account shall not be less than $1,500,000 on an average monthly basis.  Any accounts maintained outside of Bank shall be subject to an account control agreement in form and substance satisfactory to Bank.  Borrower shall provide Bank five (5) days prior written notice before establishing any account at or with any bank or financial institution other than Bank.

6.                                      Section 6.8 of the Agreement is amended in its entirety to read as follows:

6.8                                 Asset Coverage Ratio.  Borrower shall maintain at all times an Asset Coverage Ratio of at least 1.75 to 1.00, to be measured on a monthly basis.

7.                                      The following is hereby added as Section 6.11 of the Agreement as follows:

6.11                           Performance to Plan.  For quarter ending December 31, 2009, Borrower’s revenue and net loss after tax shall not negatively deviate more than 20% from the following projected amounts: revenue of $1,027,915, and a net loss of ($3,110,020).  Beginning with quarter ending March 31, 2010 and for each quarter thereafter, Borrower’s revenue and net profit/loss after tax shall not negatively deviate more than 20% from the operating projections for 2010 and beyond as approved by Borrower’s Board of Directors and delivered to Bank in accordance with Section 6.3(e).

8.                                      Exhibits B and D to the Agreement are replaced in their entirety with the Exhibits B and D attached hereto.

9.                                      As a condition to the effectiveness of this Amendment, Bank shall have received, in form and substance satisfactory to Bank, the following:

a.                                       this Amendment, duly executed by Borrower;

b.                                       corporate resolutions and incumbency certification;

c.                                       Borrower’s completed Growth Capital Advance notice pursuant to Section 2.1(b)(iii), requesting the initial Growth Capital Advance in an amount of at least $1,000,000.

2

d.                                       a nonrefundable facility fee equal to $15,000 and payment of Bank Expenses incurred in connection with this Amendment; and

e.                                       such other documents, and completion of such other matters, as Bank may reasonably deem necessary or appropriate.

10.                               Unless otherwise defined, all initially capitalized terms in this Amendment shall be as defined in the Agreement.  The Agreement, as amended hereby, shall be and remain in full force and effect in accordance with its respective terms and hereby is ratified and confirmed in all respects.  Except as expressly set forth herein, the execution, delivery, and performance of this Amendment shall not operate as a waiver of, or as an amendment of, any right, power, or remedy of Bank under the Agreement, as in effect prior to the date hereof.  Borrower ratifies and reaffirms the continuing effectiveness of all agreements entered into in connection with the Agreement.

11.                               Borrower represents and warrants that the representations and warranties contained in the Agreement are true and correct as of the date of this Amendment, and that no Event of Default has occurred and is continuing.

12.                               This Amendment may be executed in two or more counterparts, each of which shall be deemed an original, but all of which together shall constitute one instrument.

IN WITNESS WHEREOF, the undersigned have executed this Amendment as of the first date above written.

3

EXHIBIT B

GROWTH CAPITAL ADVANCE OR ADVANCE REQUEST FORM

Borrower hereby requests funding in the amount of $          in accordance with the Growth Capital Advance as defined in the Amended and Restated Loan and Security Agreement dated May 15, 2007, as amended from time to time (the “Agreement”).

Borrower hereby requests funding in the amount of $          in accordance with the Advance as defined in the Agreement.

Borrower hereby authorizes Bank to rely on facsimile stamp signatures and treat them as authorized by Borrower for the purpose of requesting the above advance.

All representations and warranties of Borrower stated in the Agreement (inclusive of the schedules and exhibits thereto) are true, correct and complete in all material respects as of the date of this request; provided that those representations and warranties expressly referring to another date shall be true, correct and complete in all material respects as of such date.

Capitalized terms used herein and not otherwise defined have the meanings set forth in the Agreement.

1

EXHIBIT D
COMPLIANCE CERTIFICATE

TO:                            BRIDGE BANK, NATIONAL ASSOCIATION

FROM:         SINGULEX, INC.

The undersigned authorized officer of Singulex, Inc. hereby certifies that in accordance with the terms and conditions of the Amended and Restated Loan and Security Agreement dated May 15, 2007 between Borrower and Bank, as amended from time to time (the “Agreement”), (i) Borrower is in complete compliance for the period ending                  with all required covenants except as noted below and (ii) all representations and warranties of Borrower stated in the Agreement are true and correct as of the date hereof.  Attached herewith are the required documents supporting the above certification.  The Officer further certifies that these are prepared in accordance with Generally Accepted Accounting Principles (GAAP) and are consistently applied from one period to the next except as explained in an accompanying letter or footnotes.

Please indicate compliance status by circling Yes/No under “Complies” column.

Comments Regarding Exceptions: See Attached.

1