As filed with the Securities and Exchange Commission on April 17, 1998.

                                                   Registration No. 333-
-------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549


                                    FORM S-8

                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933



                                  NANOGEN, INC.
--------------------------------------------------------------------------------
             (Exact name of registrant as specified in its charter)

                DELAWARE                                 33-0489621
-----------------------------------------   ------------------------------------
     (State or other jurisdiction of        (I.R.S. Employer Identification No.)
     incorporation or organization)

       10398 PACIFIC CENTER COURT
          SAN DIEGO, CALIFORNIA                             92121
-----------------------------------------   ------------------------------------
(Address of Principal Executive Offices)                 (Zip Code)

                             1993 STOCK OPTION PLAN
                         1995 STOCK OPTION/ISSUANCE PLAN
                            1997 STOCK INCENTIVE PLAN
--------------------------------------------------------------------------------
                            (Full title of the plans)

                                                          Copy to:
          HOWARD C. BIRNDORF
Chairman of the Board, Chief Executive               THOMAS E. SPARKS, JR.     
  Officer and Chief Financial Officer            Pillsbury Madison & Sutro LLP 
      10398 Pacific Center Court                         P.O. Box 7880         
          San Diego, CA 92121                    San Francisco, CA 94120-7880  
           (619) 546-7700                                (415) 983-1000        
-----------------------------------------    -----------------------------------
  (Name, address and telephone number,
including area code, of agent for service)


<TABLE>
                         CALCULATION OF REGISTRATION FEE
<CAPTION>
=========================================================================================================================
                                                     PROPOSED MAXIMUM          PROPOSED MAXIMUM
  TITLE OF SECURITIES TO       AMOUNT TO BE         OFFERING PRICE PER        AGGREGATE OFFERING          AMOUNT OF
      BE REGISTERED             REGISTERED               SHARE(1)                  PRICE(1)           REGISTRATION FEE
-------------------------------------------------------------------------------------------------------------------------
<S>                          <C>                          <C>                    <C>                       <C>   
Common Stock, par
value $0.001..............   1,514,525 shares             $11.16                 $16,902,099               $4,987
=========================================================================================================================

(1)    Estimated solely for the purpose of calculating the registration fee
pursuant to Rule 457, based upon the average of the high and low prices as
reported on the Nasdaq National Market on April 15, 1998.
</TABLE>

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

         The Registration Statement shall become effective upon filing in
accordance with Rule 462 under the Securities Act of 1933.

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

<PAGE>

                                     PART I
                                     ------

              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS
              ----------------------------------------------------

Item 1.    Plan Information.*
------     ----------------

Item 2.    Registrant Information and Employee Plan Annual Information.*
------     -----------------------------------------------------------

*          Information required by Part I to be contained in the Section 10(a)
           prospectus is omitted from this Registration Statement in accordance
           with Rule 428 under the Securities act of 1933 and the Note to Part I
           of Form S-8.


                                     PART II
                                     -------

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
               --------------------------------------------------

Item 3.    Incorporation of Certain Documents by Reference.
------     -----------------------------------------------

           The following documents filed by Registrant with the Securities and
Exchange Commission are incorporated by reference in this registration
statement:

           (1) Registrant's prospectus dated April 13, 1998 filed pursuant to
Rule 424(b) under the Securities Act of 1933 (in connection with Registrant's
Registration Statement on Form S-1, File No. 333-42791 (the "Form S-1
Registration Statement")), which contains the balance sheets of the Registrant
as of December 31, 1996 and 1997, and the related statements of operations,
stockholders' equity and cash flows for each of the three years in the period
ended December 31, 1997, together with the report thereon of Ernst & Young LLP,
independent public accountants; and

           (2) The description of Registrant's Common Stock contained in
Registrant's registration statement on Form 8-A, filed April 7, 1998.

           In addition, all documents subsequently filed by Registrant pursuant
to Sections 13(a), 13(c), 14 and 15(d) of the Securities Exchange Act of 1934,
prior to the filing of a post-effective amendment which indicates that all
securities offered have been sold or which deregisters all securities then
remaining unsold, shall be deemed to be incorporated by reference in this
registration statement and to be a part hereof from the date of filing of such
documents.

Item 4.    Description of Securities.
------     -------------------------

           Not applicable.

Item 5.    Interests of Named Experts and Counsel.
------     --------------------------------------

           The financial statements of Nanogen, Inc. incorporated by reference
in this registration statement have been audited by Ernst & Young LLP,
independent auditors, to the extent indicated in their report thereon also
incorporated by reference. Such financial statements have been incorporated
herein by


                                       -2-

<PAGE>


reference in reliance upon such report given upon the authority of said firm as
experts in auditing and accounting.

Item 6.    Indemnification of Directors and Officers.
------     -----------------------------------------

           Section 145 of the Delaware General Corporation Law provides for the
indemnification of officers, directors, and other corporate agents in terms
sufficiently broad to indemnify such persons under certain circumstances for
liabilities (including reimbursement for expenses incurred) arising under the
Securities Act of 1933, as amended (the "Act"). Article XI of the Registrant's
Restated Certificate of Incorporation (Exhibit 3.(i)3 to the Form S-1
Registration Agreement) and Article VI of the Registrant's Bylaws (Exhibit
3.(ii)2 to the Form S-1 Registration Agreement) provide for indemnification of
the Registrant's directors, officers, employees and other agents to the extent
and under the circumstances permitted by the Delaware General Corporation Law.
The Registrant has also entered into agreements with its directors and officers
that will require the Registrant, among other things, to indemnify them against
certain liabilities that may arise by reason of their status or service as
directors or officers to the fullest extent not prohibited by law (Exhibit 10.7
to the Form S-1 Registration Statement).

           The Underwriting Agreement (Exhibit 1.1 to the Form S-1 Registration
Statement) provides for indemnification by the Underwriters of the Registrant,
its directors and officers, and by the Registrant of the Underwriters, for
certain liabilities, including liabilities arising under the Act, and affords
certain rights of contribution with respect thereto.

Item 7.    Exemption from Registration Claimed.
------     -----------------------------------

           Not applicable.

Item 8.    Exhibits.
------     --------

           See Index to Exhibits.

Item 9.    Undertakings.
------     ------------

           (a)  The undersigned Registrant hereby undertakes:

                    (1) To file, during any period in which offers or sales are
           being made, a post-effective amendment to this registration
           statement:

                             (i) To include any prospectus required by section
                    10(a)(3) of the Securities Act of 1933;

                             (ii) To reflect in the prospectus any facts or
                    events arising after the effective date of the registration
                    statement (or the most recent post-effective amendment
                    thereof) which, individually or in the aggregate, represent
                    a fundamental change in the information set forth in the
                    registration statement;

                             (iii) To include any material information with
                    respect to the plan of distribution not previously disclosed
                    in the registration statement or any material change to such
                    information in the registration statement;


                                       -3-

<PAGE>

           provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) do not
           apply if the registration statement is on Form S-3 or Form S-8, and
           the information required to be included in a post-effective amendment
           by those paragraphs is contained in periodic reports filed by the
           Registrant pursuant to section 13 or section 15(d) of the Securities
           Exchange Act of 1934 that are incorporated by reference in the
           registration statement.

                    (2) That, for the purpose of determining any liability under
           the Securities Act of 1933, each such post-effective amendment shall
           be deemed to be a new registration statement relating to the
           securities offered therein, and the offering of such securities at
           that time shall be deemed to be the initial bona fide offering
           thereof.

                    (3) To remove from registration by means of a post-effective
           amendment any of the securities being registered which remain unsold
           at the termination of the offering.

           (b) The undersigned Registrant hereby further undertakes that, for
purposes of determining any liability under the Securities Act of 1933, each
filing of the Registrant's annual report pursuant to section 13(a) or section
15(d) of the Securities Exchange Act of 1934 that is incorporated by reference
in the registration statement shall be deemed to be a new registration statement
relating to the securities offered therein, and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof.

           (c) Insofar as indemnification for liabilities arising under the
Securities Act of 1933 may be permitted to directors, officers and controlling
persons of the Registrant pursuant to the foregoing provisions, or otherwise,
the Registrant has been advised that in the opinion of the Securities and
Exchange Commission such indemnification is against public policy as expressed
in the Act and is, therefore, unenforceable. In the event that a claim for
indemnification against such liabilities (other than the payment by the
Registrant of expenses incurred or paid by a director, officer or controlling
person of the Registrant in the successful defense of any action, suit or
proceeding) is asserted by such director, officer or controlling person in
connection with the securities being registered, the Registrant will, unless in
the opinion of its counsel the matter has been settled by controlling precedent,
submit to a court of appropriate jurisdiction the question whether such
indemnification by it is against public policy as expressed in the Act and will
be governed by the final adjudication of such issue.


                                       -4-

<PAGE>

                                   SIGNATURES
                                   ----------

           Pursuant to the requirements of the Securities Act of 1933, the
Registrant certifies that it has reasonable grounds to believe that it meets all
of the requirements for filing on Form S-8, and has duly caused this
registration statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of San Diego, State of California, on April 16,
1998.

                                     NANOGEN, INC.



                                     By          /s/ Howard C. Birndorf
                                       -----------------------------------------
                                                   Howard C. Birndorf
                                         Chairman of the Board, Chief Executive
                                           Officer and Chief Financial Officer



                                POWER OF ATTORNEY
                                -----------------

           KNOW ALL MEN BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints Howard C. Birndorf, Tina S. Nova, Ph.D.
and Harry J. Leonhardt, and each of them his true and lawful attorneys-in-fact
and agents, each with full power of substitution and resubstitution, for him and
in his name, place and stead, in any and all capacities, to sign any and all
amendments, including post-effective amendments, to this registration statement,
and to file the same, with exhibits thereto and other documents in connection
therewith, with the Securities and Exchange Commission, granting unto said
attorneys-in-fact and agents, full power and authority to do and perform each
and every act and thing requisite and necessary to be done, as fully to all
intents and purposes as he might or could do in person, hereby ratifying and
confirming all that said attorneys-in-fact and agents, or his substitute or
substitutes, may do or cause to be done by virtue hereof.

           Pursuant to the requirements of the Securities Act of 1933, this
registration statement has been signed by the following persons in the
capacities and on the date indicated:

         Name                           Title                         Date
         ----                           -----                         ----


 /s/ Howard C. Birndorf      Chairman of the Board, Chief         April 16, 1998
---------------------------  Executive Officer and Chief
   Howard C. Birndorf        Financial Officer (Principal
                             Executive Officer and Principal
                             Financial Officer)


                                       -5-

<PAGE>

         Name                           Title                         Date
         ----                           -----                         ----


   /s/ Dana A. Krzyston      Controller (Principal Accounting     April 16, 1998
---------------------------  Officer)
     Dana A. Krzyston        


  /s/ Tina S. Nova, Ph.D.    President and Chief Operating        April 16, 1998
---------------------------  Officer, Director
    Tina S. Nova, Ph.D.    


    /s/ Brook H. Byers       Director                             April 16, 1998
---------------------------
      Brook H. Byers


/s/ Robert E. Curry, Ph.D.   Director                             April 16, 1998
---------------------------
  Robert E. Curry, Ph.D.


     /s/ Cam L. Garner       Director                             April 16, 1998
---------------------------
       Cam L. Garner


    /s/ David Ludvigson      Director                             April 9, 1998
---------------------------
      David Ludvigson


    /s/ Thomas G. Lynch      Director                             April 16, 1998
---------------------------
      Thomas G. Lynch


/s/ Andrew E. Senyei, M.D.   Director                             April 16, 1998
---------------------------
  Andrew E. Senyei, M.D.


                                       -6-


<PAGE>


                                INDEX TO EXHIBITS
                                -----------------


Exhibit
Number                                  Exhibit
-------     --------------------------------------------------------------------

  4.1*      Specimen Common Stock Certificate.


  5.1       Opinion regarding legality of securities to be offered.


 23.1       Consent of Ernst & Young LLP, Independent Auditors.


 23.2       Consent of Pillsbury Madison & Sutro LLP (included in Exhibit 5.1).


 24.1       Power of Attorney (see page 5).


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

*    Incorporated by reference to Exhibit 4.1 to Registrant's Registration
     Statement on Form S-1, No. 333-42791.


                                       -7-
[{"type": "S-8", "sequence": "1", "description": "REGISTRATION ON FORM S-8", "secsgml_size_bytes": 17435}]
{"company-data": {"conformed-name": "NANOGEN INC", "cik": "0001030339", "assigned-sic": "3826", "irs-number": "330489621", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-50381", "film-number": "98596496"}, "business-address": {"street1": "10398 PACIFIC CENTER COURT", "street2": "619-546-7700", "city": "SAN DIEGO", "state": "CA", "zip": "92121", "phone": "6195467700"}, "mail-address": {"street1": "10398 PACIFIC CENTER COURT", "city": "SAN DIEGO", "state": "CA", "zip": "92121"}}
As filed with the Securities and Exchange Commission on April 17, 1998.

                                                   Registration No. 333-
-------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM S-8

                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                                  NANOGEN, INC.
--------------------------------------------------------------------------------
             (Exact name of registrant as specified in its charter)

                DELAWARE                                 33-0489621
-----------------------------------------   ------------------------------------
     (State or other jurisdiction of        (I.R.S. Employer Identification No.)
     incorporation or organization)

       10398 PACIFIC CENTER COURT
          SAN DIEGO, CALIFORNIA                             92121
-----------------------------------------   ------------------------------------
(Address of Principal Executive Offices)                 (Zip Code)

                             1993 STOCK OPTION PLAN
                         1995 STOCK OPTION/ISSUANCE PLAN
                            1997 STOCK INCENTIVE PLAN
--------------------------------------------------------------------------------
                            (Full title of the plans)

                                                          Copy to:
          HOWARD C. BIRNDORF
Chairman of the Board, Chief Executive               THOMAS E. SPARKS, JR.     
  Officer and Chief Financial Officer            Pillsbury Madison & Sutro LLP 
      10398 Pacific Center Court                         P.O. Box 7880         
          San Diego, CA 92121                    San Francisco, CA 94120-7880  
           (619) 546-7700                                (415) 983-1000        
-----------------------------------------    -----------------------------------
  (Name, address and telephone number,
including area code, of agent for service)

                         CALCULATION OF REGISTRATION FEE
=========================================================================================================================
                                                     PROPOSED MAXIMUM          PROPOSED MAXIMUM
  TITLE OF SECURITIES TO       AMOUNT TO BE         OFFERING PRICE PER        AGGREGATE OFFERING          AMOUNT OF
      BE REGISTERED             REGISTERED               SHARE(1)                  PRICE(1)           REGISTRATION FEE
-------------------------------------------------------------------------------------------------------------------------
Common Stock, par
value $0.001..............   1,514,525 shares             $11.16                 $16,902,099               $4,987
=========================================================================================================================

(1)    Estimated solely for the purpose of calculating the registration fee
pursuant to Rule 457, based upon the average of the high and low prices as
reported on the Nasdaq National Market on April 15, 1998.
-----------------

         The Registration Statement shall become effective upon filing in
accordance with Rule 462 under the Securities Act of 1933.

--------------------------------------------------------------------------------
PART I
                                     ------

              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS
              ----------------------------------------------------

Item 1.    Plan Information.*
------     ----------------

Item 2.    Registrant Information and Employee Plan Annual Information.*
------     -----------------------------------------------------------

*          Information required by Part I to be contained in the Section 10(a)
           prospectus is omitted from this Registration Statement in accordance
           with Rule 428 under the Securities act of 1933 and the Note to Part I
           of Form S-8.

                                     PART II
                                     -------

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
               --------------------------------------------------

Item 3.    Incorporation of Certain Documents by Reference.
------     -----------------------------------------------

           The following documents filed by Registrant with the Securities and
Exchange Commission are incorporated by reference in this registration
statement:

           (1) Registrant's prospectus dated April 13, 1998 filed pursuant to
Rule 424(b) under the Securities Act of 1933 (in connection with Registrant's
Registration Statement on Form S-1, File No. 333-42791 (the "Form S-1
Registration Statement")), which contains the balance sheets of the Registrant
as of December 31, 1996 and 1997, and the related statements of operations,
stockholders' equity and cash flows for each of the three years in the period
ended December 31, 1997, together with the report thereon of Ernst & Young LLP,
independent public accountants; and

           (2) The description of Registrant's Common Stock contained in
Registrant's registration statement on Form 8-A, filed April 7, 1998.

           In addition, all documents subsequently filed by Registrant pursuant
to Sections 13(a), 13(c), 14 and 15(d) of the Securities Exchange Act of 1934,
prior to the filing of a post-effective amendment which indicates that all
securities offered have been sold or which deregisters all securities then
remaining unsold, shall be deemed to be incorporated by reference in this
registration statement and to be a part hereof from the date of filing of such
documents.

Item 4.    Description of Securities.
------     -------------------------

           Not applicable.

Item 5.    Interests of Named Experts and Counsel.
------     --------------------------------------

           The financial statements of Nanogen, Inc. incorporated by reference
in this registration statement have been audited by Ernst & Young LLP,
independent auditors, to the extent indicated in their report thereon also
incorporated by reference. Such financial statements have been incorporated
herein by

                                       -2-
reference in reliance upon such report given upon the authority of said firm as
experts in auditing and accounting.

Item 6.    Indemnification of Directors and Officers.
------     -----------------------------------------

           Section 145 of the Delaware General Corporation Law provides for the
indemnification of officers, directors, and other corporate agents in terms
sufficiently broad to indemnify such persons under certain circumstances for
liabilities (including reimbursement for expenses incurred) arising under the
Securities Act of 1933, as amended (the "Act"). Article XI of the Registrant's
Restated Certificate of Incorporation (Exhibit 3.(i)3 to the Form S-1
Registration Agreement) and Article VI of the Registrant's Bylaws (Exhibit
3.(ii)2 to the Form S-1 Registration Agreement) provide for indemnification of
the Registrant's directors, officers, employees and other agents to the extent
and under the circumstances permitted by the Delaware General Corporation Law.
The Registrant has also entered into agreements with its directors and officers
that will require the Registrant, among other things, to indemnify them against
certain liabilities that may arise by reason of their status or service as
directors or officers to the fullest extent not prohibited by law (Exhibit 10.7
to the Form S-1 Registration Statement).

           The Underwriting Agreement (Exhibit 1.1 to the Form S-1 Registration
Statement) provides for indemnification by the Underwriters of the Registrant,
its directors and officers, and by the Registrant of the Underwriters, for
certain liabilities, including liabilities arising under the Act, and affords
certain rights of contribution with respect thereto.

Item 7.    Exemption from Registration Claimed.
------     -----------------------------------

           Not applicable.

Item 8.    Exhibits.
------     --------

           See Index to Exhibits.

Item 9.    Undertakings.
------     ------------

           (a)  The undersigned Registrant hereby undertakes:

                    (1) To file, during any period in which offers or sales are
           being made, a post-effective amendment to this registration
           statement:

                             (i) To include any prospectus required by section
                    10(a)(3) of the Securities Act of 1933;

                             (ii) To reflect in the prospectus any facts or
                    events arising after the effective date of the registration
                    statement (or the most recent post-effective amendment
                    thereof) which, individually or in the aggregate, represent
                    a fundamental change in the information set forth in the
                    registration statement;

                             (iii) To include any material information with
                    respect to the plan of distribution not previously disclosed
                    in the registration statement or any material change to such
                    information in the registration statement;

                                       -3-
provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) do not
           apply if the registration statement is on Form S-3 or Form S-8, and
           the information required to be included in a post-effective amendment
           by those paragraphs is contained in periodic reports filed by the
           Registrant pursuant to section 13 or section 15(d) of the Securities
           Exchange Act of 1934 that are incorporated by reference in the
           registration statement.

                    (2) That, for the purpose of determining any liability under
           the Securities Act of 1933, each such post-effective amendment shall
           be deemed to be a new registration statement relating to the
           securities offered therein, and the offering of such securities at
           that time shall be deemed to be the initial bona fide offering
           thereof.

                    (3) To remove from registration by means of a post-effective
           amendment any of the securities being registered which remain unsold
           at the termination of the offering.

           (b) The undersigned Registrant hereby further undertakes that, for
purposes of determining any liability under the Securities Act of 1933, each
filing of the Registrant's annual report pursuant to section 13(a) or section
15(d) of the Securities Exchange Act of 1934 that is incorporated by reference
in the registration statement shall be deemed to be a new registration statement
relating to the securities offered therein, and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof.

           (c) Insofar as indemnification for liabilities arising under the
Securities Act of 1933 may be permitted to directors, officers and controlling
persons of the Registrant pursuant to the foregoing provisions, or otherwise,
the Registrant has been advised that in the opinion of the Securities and
Exchange Commission such indemnification is against public policy as expressed
in the Act and is, therefore, unenforceable. In the event that a claim for
indemnification against such liabilities (other than the payment by the
Registrant of expenses incurred or paid by a director, officer or controlling
person of the Registrant in the successful defense of any action, suit or
proceeding) is asserted by such director, officer or controlling person in
connection with the securities being registered, the Registrant will, unless in
the opinion of its counsel the matter has been settled by controlling precedent,
submit to a court of appropriate jurisdiction the question whether such
indemnification by it is against public policy as expressed in the Act and will
be governed by the final adjudication of such issue.

                                       -4-
SIGNATURES
                                   ----------

           Pursuant to the requirements of the Securities Act of 1933, the
Registrant certifies that it has reasonable grounds to believe that it meets all
of the requirements for filing on Form S-8, and has duly caused this
registration statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of San Diego, State of California, on April 16,
1998.

                                     NANOGEN, INC.

                                     By          /s/ Howard C. Birndorf
                                       -----------------------------------------
                                                   Howard C. Birndorf
                                         Chairman of the Board, Chief Executive
                                           Officer and Chief Financial Officer

                                POWER OF ATTORNEY
                                -----------------

           KNOW ALL MEN BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints Howard C. Birndorf, Tina S. Nova, Ph.D.
and Harry J. Leonhardt, and each of them his true and lawful attorneys-in-fact
and agents, each with full power of substitution and resubstitution, for him and
in his name, place and stead, in any and all capacities, to sign any and all
amendments, including post-effective amendments, to this registration statement,
and to file the same, with exhibits thereto and other documents in connection
therewith, with the Securities and Exchange Commission, granting unto said
attorneys-in-fact and agents, full power and authority to do and perform each
and every act and thing requisite and necessary to be done, as fully to all
intents and purposes as he might or could do in person, hereby ratifying and
confirming all that said attorneys-in-fact and agents, or his substitute or
substitutes, may do or cause to be done by virtue hereof.

           Pursuant to the requirements of the Securities Act of 1933, this
registration statement has been signed by the following persons in the
capacities and on the date indicated:

         Name                           Title                         Date
         ----                           -----                         ----

 /s/ Howard C. Birndorf      Chairman of the Board, Chief         April 16, 1998
---------------------------  Executive Officer and Chief
   Howard C. Birndorf        Financial Officer (Principal
                             Executive Officer and Principal
                             Financial Officer)

                                       -5-
Name                           Title                         Date
         ----                           -----                         ----

   /s/ Dana A. Krzyston      Controller (Principal Accounting     April 16, 1998
---------------------------  Officer)
     Dana A. Krzyston        

  /s/ Tina S. Nova, Ph.D.    President and Chief Operating        April 16, 1998
---------------------------  Officer, Director
    Tina S. Nova, Ph.D.    

    /s/ Brook H. Byers       Director                             April 16, 1998
---------------------------
      Brook H. Byers

/s/ Robert E. Curry, Ph.D.   Director                             April 16, 1998
---------------------------
  Robert E. Curry, Ph.D.

     /s/ Cam L. Garner       Director                             April 16, 1998
---------------------------
       Cam L. Garner

    /s/ David Ludvigson      Director                             April 9, 1998
---------------------------
      David Ludvigson

    /s/ Thomas G. Lynch      Director                             April 16, 1998
---------------------------
      Thomas G. Lynch

/s/ Andrew E. Senyei, M.D.   Director                             April 16, 1998
---------------------------
  Andrew E. Senyei, M.D.

                                       -6-
INDEX TO EXHIBITS
                                -----------------

Exhibit
Number                                  Exhibit
-------     --------------------------------------------------------------------

  4.1*      Specimen Common Stock Certificate.

  5.1       Opinion regarding legality of securities to be offered.

 23.1       Consent of Ernst & Young LLP, Independent Auditors.

 23.2       Consent of Pillsbury Madison & Sutro LLP (included in Exhibit 5.1).

 24.1       Power of Attorney (see page 5).

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

*    Incorporated by reference to Exhibit 4.1 to Registrant's Registration
     Statement on Form S-1, No. 333-42791.

                                       -7-