<PAGE>

                                                                    Exhibit 10.2


                           STRATEGIC DIAGNOSTICS, INC.

                         NONQUALIFIED STOCK OPTION GRANT
                         -------------------------------


         This STOCK OPTION GRANT (the "Agreement"), dated as of September 2,
2003 (the "Date of Grant"), is delivered by Strategic Diagnostics, Inc. (the
"Company") to Matthew Knight (the "Grantee").

                                    RECITALS
                                    --------

         WHEREAS, the Company desires to employ the Grantee and the Grantee
desires to become employed by the Company; and

         WHEREAS, the Board of Directors of the Company (the "Board") has
decided to grant a nonqualified stock option to the Grantee in connection with
his acceptance of employment with the Company and as an inducement for the
Grantee to promote the best interests of the Company and its stockholders; and

         WHEREAS, the Company maintains the Strategic Diagnostics Inc. 2000
Stock Incentive Plan, as amended through March 16, 2001 (the "Plan"); and

         WHEREAS, this nonqualified stock option grant is made outside of the
Plan; and

         WHEREAS, although this nonqualified stock option grant is being made
outside the Plan, where noted, terms herein shall have the same meaning as such
terms have under the Plan; and

         WHEREAS, except as specifically indicated otherwise, all references in
this Agreement to the "Board" shall be deemed to refer to the Compensation
Committee.

         NOW, THEREFORE, the parties to this Agreement, intending to be legally
bound hereby, agree as follows:

1.       Grant of Option. Subject to the terms and conditions set forth in this
Agreement, the Company hereby grants to the Grantee a nonqualified stock option
(the "Option") to purchase 300,000 shares of common stock of the Company
("Shares") at an exercise price of $4.00 per Share. The Option shall become
exercisable according to Section 2 below.

2.       Exercisability of Option.

         (a) The Option shall become exercisable as of the following dates, if
the Grantee is providing service to the Company as of the applicable date:

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                                                                    Exhibit 10.2


------------------------------------- ------------------------------------------
                DATE                           PERCENTAGE OF SHARES FOR
                                           WHICH THE OPTION IS EXERCISABLE

------------------------------------- ------------------------------------------
       Date of Grant + 1 year                            33-1/3%

------------------------------------- ------------------------------------------
       Date of Grant + 2 years                           33-1/3%

------------------------------------- ------------------------------------------
       Date of Grant + 3 years                           33-1/3%

------------------------------------- ------------------------------------------


         (b) Notwithstanding the provisions of Section 2(a) above, if the
Grantee's employment terminates on account of (i) termination by the Company
without Cause (as defined in the written employment agreement between the
Grantee and the Company dated September 2, 2003 (the "Employment Agreement")),
(ii) the Grantee's resignation for Good Reason (as defined in the Employment
Agreement) or (iii) Non-Renewal (as defined in the Employment Agreement) and the
Grantee executes and does not revoke the Release (as defined in the Employment
Agreement), the Option shall automatically accelerate and become fully
exercisable.

         (c) Notwithstanding the provisions of Sections 2(a) and 2(b) above, if
a Change of Control (as defined in the Plan) occurs, the Option shall
automatically accelerate and become fully exercisable.

The exercisability of the Option is cumulative, but shall not exceed 100%. The
Option shall be fully exercisable on September 2, 2006, if the Grantee is then
providing service to the Company.

3.       Term of Option.

         (a) The Option shall have a term of ten years from the Date of Grant
and shall terminate at the expiration of that period, unless it is terminated at
an earlier date pursuant to the provisions of this Agreement.

         (b) The Option shall automatically terminate upon the happening of the
first of the following events:

                  (i) The expiration of the 90-day period after the Grantee
         ceases to be employed by the Company, if (A) the termination is on
         account of the Grantee's resignation other than for Good Reason (as
         defined in the Employment Agreement) or (B) in connection with the
         Grantee's termination without Cause (as defined in the Employment

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                                                                    Exhibit 10.2

         Agreement), resignation for Good Reason (as defined in the Employment
         Agreement) or Non-Renewal (as defined in the Employment Agreement), the
         Grantee fails to execute or revokes the Release (as defined in the
         Employment Agreement);

                  (ii) The expiration of the 90-day period commencing with the
         expiration of the Severance Period (as defined in the Employment
         Agreement), if the termination for any reason other than Disability (as
         defined in the Employment Agreement), death, Cause (as defined in the
         Employment Agreement) or resignation by the Grantee other than for Good
         Reason (as defined in the Employment Agreement); provided that the
         Grantee executes and does not revoke the Release (as defined in the
         Employment Agreement);

                  (iii) The expiration of the one year period after the Grantee
         ceases to be employed by the Company on account of the Grantee's
         Disability (as defined in the Employment Agreement);

                  (iv) The expiration of the 180-day period after the death of
         Grantee while employed by the Company; or

                  (v) The date on which the Grantee ceases to be employed by the
         Company for Cause (as defined in the Employment Agreement). In
         addition, notwithstanding the prior provisions of this Paragraph 3, if
         the Board determines that the Grantee has engaged in conduct that
         constitutes Cause at any time while the Grantee is providing service to
         the Company or after the Grantee's service terminates, the Option shall
         immediately terminate, and the Grantee shall automatically forfeit all
         shares underlying any exercised portion of an Option for which the
         Company has not yet delivered the share certificates, upon refund by
         the Company of the exercise price paid by the Grantee for such shares.

Notwithstanding the foregoing, in no event may the Option be exercised after the
date that is ten years from the Date of Grant. Any portion of the Option that is
not exercisable at the time the Grantee ceases to be employed by, or provide
service to, the Company shall immediately terminate.

4.       Exercise Procedures.

         (a) Subject to the provisions of Sections 2 and 3 above, the Grantee
may exercise part or all of the exercisable Option by giving the Board written
notice of intent to exercise, in a form and manner prescribed by the Board,
specifying the number of Shares as to which the Option is to be exercised. On
the delivery date, the Grantee shall pay the exercise price (i) in cash, (ii)
with the approval of the Board, by delivering Shares of the Company which shall
be valued at their Fair Market Value (as defined in the Plan) on the date of
delivery, or (iii) by such other method as the Board may approve, including,
after a Public Offering (as defined in the Plan) of the Company's stock, payment
through a broker in accordance with procedures permitted by Regulation T of the
Federal Reserve Board. The Board may impose from time to time such limitations
as it deems appropriate on the use of shares of Company stock to exercise the
Option.

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                                                                    Exhibit 10.2

         (b) The obligation of the Company to deliver share certificates upon
exercise of the Option shall be subject to all applicable laws, rules, and
regulations and such approvals by governmental agencies as may be deemed
appropriate by the Board, including such actions as Company counsel shall deem
necessary or appropriate to comply with relevant securities laws and
regulations. The Company may require that the Grantee (or other person
exercising the Option after the Grantee's death) represent that the Grantee is
purchasing the Shares for the Grantee's own account and not with a view to or
for sale in connection with any distribution of the Shares, or such other
representation as the Board deems appropriate. All obligations of the Company
under this Agreement shall be subject to the rights of the Company as set forth
in Paragraph 8 to withhold amounts required to be withheld for any taxes, if
applicable.

         5. Change of Control of the Company. Except as otherwise provided in
this Agreement, the provisions of the Plan applicable to a Change of Control
shall apply to the Option, and, in the event of a Change of Control, the Board
may take such actions as it deems appropriate.

         6. Withholding of Taxes

         (a) Required Withholding. The Option shall be subject to applicable
federal (including FICA), state and local tax withholding requirements. The
Grantee or other person receiving or exercising the Option shall be required to
pay to the Company the amount of any such taxes that the Company is required to
withhold with respect to the Option, or to allow the Company to deduct from
other wages paid by the Company the amount of any withholding taxes due with
respect to the Option.

         (b) Election to Withhold Shares. The Grantee may elect to satisfy the
Company's income tax withholding obligation with respect to the Option by having
shares withheld up to an amount that does not exceed the Grantee's minimum
applicable withholding tax rate for federal (including FICA), state and local
tax liabilities. The election must be in a form and manner prescribed by the
Board.

         7. Transferability; Restrictions on Exercise. The Option shall not be
transferable by the Grantee other than by will or by the laws of descent and
distribution. Only the Grantee may exercise the Option during the Grantee's
lifetime. After the Grantee's death, the Option shall be exercisable solely by
the legal representatives of the Grantee, or by the person who acquires the
right to exercise the Option by will or by the laws of descent and distribution,
to the extent that the Option is exercisable pursuant to this Agreement.

                                      -4-

<PAGE>

         8. Option Subject to Board Determinations. The grant and exercise of
the Option are subject to interpretations, regulations and determinations
established from time to time by the Board including, but not limited to,
provisions pertaining to (i) rights and obligations with respect to withholding
taxes, (ii) the registration, qualification or listing of the Shares, (iii)
changes in capitalization of the Company, and (iv) other requirements of
applicable law. The Board shall have the authority to interpret and construe the
Option, and its decisions shall be conclusive as to any questions arising
hereunder.

         9. No Employment or Other Rights. The grant of the Option shall not
confer upon the Grantee any right to be retained by or in the employ or service
of the Company and shall not interfere in any way with the right of the Company
to terminate the Grantee's employment or service at any time. The right of the
Company to terminate at will the Grantee's employment or service at any time for
any reason is specifically reserved, except as may be otherwise provided in the
written employment agreement between the Grantee and the Company, dated
September 2, 2003.

         10. No Stockholder Rights. Neither the Grantee, nor any person entitled
to exercise the Grantee's rights in the event of the Grantee's death, shall have
any of the rights and privileges of a stockholder with respect to the Shares
subject to the Option, until certificates for Shares have been issued upon the
exercise of the Option.

         11. Assignment. The rights and interests of the Grantee under this
Agreement may not be sold, assigned, encumbered or otherwise transferred except,
in the event of the death of the Grantee, by will or by the laws of descent and
distribution. In the event of any attempt by the Grantee to alienate, assign,
pledge, hypothecate, or otherwise dispose of the Option or any right hereunder,
except as provided for in this Agreement, or in the event of the levy or any
attachment, execution or similar process upon the rights or interests hereby
conferred, the Company may terminate the Option by notice to the Grantee, and
the Option and all rights hereunder shall thereupon become null and void. The
rights and protections of the Company hereunder shall extend to any successors
or assigns of the Company and to the Company's parents, subsidiaries, and
affiliates. This Agreement may be assigned by the Company without the Grantee's
consent.

         12. Applicable Law. The validity, construction, interpretation and
effect of this Agreement shall be governed by and construed in accordance with
the laws of the State of Delaware, without giving effect to the conflicts of
laws provisions thereof.

         13. Notice. Any notice to the Company provided for in this Agreement
shall be addressed to the Company in care of the Chief Financial Officer at
Strategic Diagnostics Inc., 111 Pencader Drive, Newark, DE 19702, and any notice
to the Grantee shall be addressed to such Grantee at the current address shown
on the payroll of the Company, or to such other address as the Grantee may
designate to the Company in writing. Any notice shall be delivered by hand, sent

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                                                                    Exhibit 10.2

by telecopy or enclosed in a properly sealed envelope addressed as stated above,
registered and deposited, postage prepaid, in a post office regularly maintained
by the United States Postal Service.

                            [SIGNATURE PAGE FOLLOWS]














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                                                                    Exhibit 10.2

IN WITNESS WHEREOF, the Company has caused its duly authorized officers to
execute and attest this Agreement, and the Grantee has executed this Agreement,
effective as of the Date of Grant.

                                      STRATEGIC DIAGNOSTICS, INC.


                                      By: /s/ Grover C. Wrenn
                                          -------------------



I hereby accept the Option grant described in this Agreement. I have read the
Strategic Diagnostics, Inc. 2000 Stock Incentive Plan, as amended through March
16, 2001 and I understand that the capitalized terms herein where indicated
shall have the same meaning as those terms have under the Plan. I hereby agree
to be bound by those terms and the terms of this Agreement and any
determinations of the Board with respect thereto.

                                       Accepted:/s/ Matthew H. Knight
                                                ----------------------
                                                     Grantee






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