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                                                                     EXHIBIT 4.1

              Amendment No. 1 to Public Relations Warrant Agreement
                                       and
                               Warrant Certificate

         AMENDMENT NO. 1 dated October 30, 1999, to Public Relations Warrant
Agreement (the "Warrant Agreement") dated April 18, 1997 by and between
Matritech, Inc., a Delaware corporation (the "Company") and Sunrise Financial
Group, Inc. ("Sunrise") and to the corresponding Warrant Certificate No. PRW-1
(the "Warrant Certificate," together with the Warrant Agreement, the "Warrant").

         The parties hereto, in consideration of the premises and agreements
herein contained and intending to be legally bound hereby, agree as follows:

         1.       The Warrant Price (as such term is defined in both the Warrant
                  Agreement and the Warrant Certificate) is hereby reduced from
                  six dollars and fifty cents ($6.50) to two dollars and fifty
                  cents ($2.50).
         2.       Section 3(b) of the Warrant Agreement and the last sentence of
                  the second paragraph of the Warrant Certificate are deleted in
                  their entirety, and accordingly, from the date hereof the
                  Warrant may only be exercised by payment of the Warrant Price
                  in cash or by certified or cashier's check.
         3.       Sunrise and Nathan Low acknowledge that the Warrant and the
                  securities issuable upon exercise of the Warrant have not been
                  registered under the United States Securities Act of 1933, as
                  amended (the "Act"), and as such may not be sold, assigned,
                  exchanged, hypothecated or otherwise transferred without
                  registration of such securities under the Act or compliance
                  with an exemption therefrom.
         4.       The Company agrees to file as soon as practicable, but in no
                  event later than 45 days from the date hereof, a registration
                  statement on Form S-3 with the Securities and Exchange
                  Commission registering the resale of all of the securities
                  underlying the Warrant.

         5.       This Amendment No. 1 may be signed in multiple counterparts,
                  each of which shall be deemed an original, but all taken
                  together shall constitute one agreement.


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         IN WITNESS WHEREOF, the parties have caused the Amendment No. 1 to be
duly executed as of the day and year first above written.


MATRITECH, INC.                             SUNRISE FINANCIAL GROUP, INC.


By: /s/ Stephen D. Chubb                    By: /s/ Nathan Low
    --------------------------------            -------------------------------
        Stephen D. Chubb                            Nathan Low
        Chairman and Chief Executive
        Officer

                                                /s/ Nathan Low
                                                -------------------------------
                                                    NATHAN LOW