RESTATED CERTIFICATE OF INCORPORATION
 
                                       OF
 
                                  NANOGEN, INC.
 
         NANOGEN, INC., a corporation organized and existing under the laws 
of the State of Delaware, hereby certifies as follows:
 
                  FIRST:  The name of this corporation is Nanogen, Inc.
 
                  SECOND: The original Certificate of Incorporation of the
         corporation was filed with the Secretary of State of the State of
         Delaware on September 10, 1997 and the original name of the corporation
         was Nanogen (Delaware), Inc. A Restated Certificate of Incorporation of
         the corporation was filed with the Secretary of State of the State of
         Delaware on November 7, 1997. A Certificate of Merger whereby Nanogen,
         Inc., a California corporation, was merged with and into this
         corporation and this corporation's name was changed to Nanogen, Inc.
         was filed with the Secretary of State of the State of Delaware on
         November 10, 1997. Certificate of Amendments were filed with the
         Secretary of State of the State of Delaware on January 28, 1998 and
         April 6, 1998.
 
                  THIRD: The Restated Certificate of Incorporation of said
         corporation shall be amended and restated to read in full as follows:
 
 
                                    ARTICLE I
 
         The name of this corporation is NANOGEN, INC..
 
 
                                   ARTICLE II
 
         The registered office of the corporation within the State of Delaware
is located at 1209 Orange Street, in the City of Wilmington, County of New
Castle. The name of its registered agent at such address is The Corporation
Trust Company.
 
 
                                   ARTICLE III
 
         The purpose of this corporation is to engage in any lawful act or
activity for which a corporation may be organized under the General Corporation
Law of Delaware.
 
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                                   ARTICLE IV
 
         A.   AUTHORIZED STOCK. The total number of shares of all classes of 
capital stock which the corporation shall have authority to issue is 
fifty-five million (55,000,000), of which fifty million (50,000,000) shares 
of the par value of one tenth of one cent ($.001) each shall be Common Stock 
(the "Common Stock") and five million (5,000,000) shares of the par value of 
one tenth of one cent ($.001) each shall be Preferred Stock (the "Preferred 
Stock"). The number of authorized shares of Common Stock or Preferred Stock 
may be increased or decreased (but not below the number of shares thereof 
then outstanding) by the affirmative vote of the holders of a majority of the 
then outstanding shares of Common Stock, without a vote of the holders of the 
Preferred Stock, or of any series thereof, unless a vote of any such 
Preferred Stock holders is required pursuant to the provisions established by 
the Board of Directors of this corporation (the "Board of Directors") in the 
resolution or resolutions providing for the issue of such Preferred Stock, 
and if such holders of such Preferred Stock are so entitled to vote thereon, 
then, except as may otherwise be set forth in this Restated Certificate of 
Incorporation, the only stockholder approval required shall be the 
affirmative vote of a majority of the combined voting power of the Common 
Stock and the Preferred Stock so entitled to vote.
 
         B.   PREFERRED STOCK. The Preferred Stock may be issued in any 
number of series, as determined by the Board of Directors. The Board of 
Directors may by resolution fix the designation and number of shares of any 
such series, and may determine, alter, or revoke the rights, preferences, 
privileges and restrictions granted to or imposed upon any wholly unissued 
series. The Board of Directors may thereafter in the same manner, within the 
limits and restrictions stated in any resolution or resolutions of the Board 
of Directors originally fixing the number of shares constituting any series, 
increase or decrease the number of shares of any such series (but not below 
the number of shares of that series then outstanding). In case the number of 
shares of any series shall be decreased, the shares constituting such 
decrease shall resume the status which they had prior to the adoption of the 
resolution originally fixing the number of shares of such series.
 
         C.   COMMON STOCK.
 
              1.   RELATIVE RIGHTS OF PREFERRED STOCK AND COMMON STOCK. All
         preferences, voting powers, relative, participating, optional or other
         special rights and privileges, and qualifications, limitations or
         restrictions of the Common Stock are expressly made subject and
         subordinate to those that may be fixed with respect to any shares of
         the Preferred Stock.
 
              2.   VOTING RIGHTS. Except as otherwise required by law or this
         Restated Certificate of Incorporation, each holder of Common Stock
         shall have one vote in respect of each share of stock held by such
         holder of record on the books of the corporation for the election of
         directors and on all matters submitted to a vote of stockholders of the
         corporation.
 
              3.   DIVIDENDS. Subject to the preferential rights of the
         Preferred Stock, if any, the holders of shares of Common Stock shall be
         entitled to receive, when and if declared by the Board of Directors,
         out of the assets of the corporation which are by law available
         therefor, dividends payable either in cash, in property or in shares 
 
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         of capital stock.
 
              4.   LIQUIDATION, DISSOLUTION OR WINDING UP. In the event of any
         dissolution, liquidation or winding up of the affairs of the
         corporation, after distribution in full of the preferential amounts, if
         any, to be distributed to the holders of shares of the Preferred Stock,
         holders of Common Stock shall be entitled, unless otherwise provided by
         law or this Restated Certificate of Incorporation, to receive all of
         the remaining assets of the corporation of whatever kind available for
         distribution to stockholders ratably in proportion to the number of
         shares of Common Stock held by them respectively.
 
 
                                    ARTICLE V
 
         The corporation is to have perpetual existence.
 
 
                                   ARTICLE VI
 
         A.   CLASSIFIED BOARD. The Board of Directors shall be divided into 
three classes, designated Class I, Class II and Class III, as nearly equal in 
number as possible, and the term of office of directors of one class shall 
expire at each annual meeting of stockholders, and in all cases as to each 
director when such director's successor shall be elected and shall qualify or 
upon such director's earlier resignation, removal from office, death or 
incapacity. Additional directorships resulting from an increase in number of 
directors shall be apportioned among the classes as equally as possible. At 
each annual meeting of stockholders the number of directors equal to the 
number of directors of the class whose term expires at the time of such 
meeting (or, if less, the number of directors properly nominated and 
qualified for election) shall be elected to hold office until the third 
succeeding annual meeting of stockholders after their election.
 
         B.   CHANGES. The Board of Directors of this corporation, by 
amendment to the corporation's bylaws, is expressly authorized to change the 
number of directors in any or all of the classes of directors without the 
consent of the stockholders.
 
         C.   ELECTIONS. Elections of directors need not be by written ballot 
unless the Bylaws of the corporation shall so provide.
 
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                                   ARTICLE VII
 
         A.   POWER OF STOCKHOLDER TO ACT BY WRITTEN CONSENT. No action 
required or permitted to be taken at any annual or special meeting of the 
stockholders may be taken without a meeting and the power of stockholders to 
consent in writing, without a meeting, to the taking of any action is 
specifically denied.
 
         B.   SPECIAL MEETINGS OF STOCKHOLDERS. Special meetings of the 
stockholders of the corporation may be called for any purpose or purposes, 
unless otherwise prescribed by statute or by this Restated Certificate of 
Incorporation, only at the request of the Chairman of the Board of Directors, 
the Chief Executive Officer or President of the corporation or by a 
resolution duly adopted by the affirmative vote of a majority of the Board of 
Directors.
 
 
                                  ARTICLE VIII
 
         The Board of Directors is expressly empowered to adopt, amend or 
repeal the Bylaws of the corporation; provided, however, that any adoption, 
amendment or repeal of the Bylaws of the corporation by the Board of 
Directors shall require the approval of at least sixty-six and two-thirds 
percent (66 2/3%) of the total number of authorized directors (whether or not 
there exist any vacancies in previously authorized directorships at the time 
any resolution providing for adoption, amendment or repeal is presented to 
the Board of Directors). The stockholders shall also have the power to adopt, 
amend or repeal the Bylaws of the corporation, provided, however, that in 
addition to any vote of the holders of any class or series of stock of the 
corporation required by law or by this Restated Certificate of Incorporation, 
the affirmative vote of the holders of at least sixty-six and two-thirds 
percent (66 2/3%) of the voting power of all of the then outstanding shares 
of the stock of the corporation entitled to vote generally in the election of 
directors, voting together as a single class, shall be required for such 
adoption, amendment or repeal by the stockholders of any provisions of the 
Bylaws of the corporation.
 
 
                                   ARTICLE IX
 
         The books of the corporation may be kept at such place within or 
without the State of Delaware as the bylaws of the corporation may provide or 
as may be designated from time to time by the board of directors of the 
corporation.
 
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                                    ARTICLE X
 
         Whenever a compromise or arrangement is proposed between the 
corporation and its creditors or any class of them and/or between the 
corporation and its stockholders or any class of them, any court of equitable 
jurisdiction within the State of Delaware may, on the application in a 
summary way of the corporation or of any creditor or stockholder thereof or 
on the application of any receivers appointed for the corporation under the 
provisions of section 291 of Title 8 of the Delaware Code or on the 
application of trustees in dissolution or of any receiver or receivers 
appointed for the corporation under the provisions of section 279 of Title 8 
of the Delaware Code order a meeting of the creditors or class of creditors, 
and/or the stockholders or class of stockholders of the corporation, as the 
case may be, to be summoned in such manner as the said court directs. If a 
majority, in number representing three-fourths in value of the creditors or 
class of creditors, and/or of the stockholders or class of stockholders of 
the corporation, as the case may be, agree to any compromise or arrangement 
and to any reorganization of this corporation as consequence of such 
compromise or arrangement, the said compromise or arrangement and the said 
reorganization shall if sanctioned by the court to which the said application 
has been made, be binding on all the creditors or class of creditors, and/or 
on all the stockholders or class of stockholders, of the corporation, as the 
case may be, and also on the corporation.
 
 
                                   ARTICLE XI
 
         A.   LIMITATION ON LIABILITY. A director of the corporation shall 
not be personally liable to the corporation or its stockholders for monetary 
damages for breach of fiduciary duty as a director, except for liability (1) 
for any breach of the director's duty of loyalty to the corporation or its 
stockholders; (2) for acts or omissions not in good faith or which involve 
intentional misconduct or a knowing violation of law; (3) under Section 174 
of the Delaware General Corporation Law; or (4) for any transaction from 
which the director derived an improper personal benefit.
 
         If the Delaware General Corporation Law hereafter is amended to 
further eliminate or limit the liability of directors, then the liability of 
a director of the corporation, in addition to the limitation on personal 
liability provided herein, shall be limited to the fullest extent permitted 
by the amended Delaware General Corporation Law.
 
         B.   INDEMNIFICATION. Each person who is or is made a party or is 
threatened to be made a party to or is involved in any action, suit or 
proceeding, whether civil, criminal, administrative or investigative 
(hereinafter a "proceeding"), by reason of the fact that he or she, or a 
person of whom he or she is the legal representative, is or was a director or 
officer of the corporation or is or was serving at the request of the 
corporation as a director, officer, employee or agent of another corporation 
or of a partnership, joint venture, trust or other enterprise, including 
service with respect to employee benefit plans, whether the basis of such 
proceeding is alleged action in an official capacity as a director, officer, 
employee or agent or in any other capacity while serving as a director, 
officer, employee or agent, shall be indemnified and held harmless by the 
corporation to the fullest extent authorized by the Delaware General 
Corporation Law, as the same exists or may hereafter be amended (but, in the 
case of any such amendment, only to the extent that such amendment permits 
the corporation to provide broader indemnification rights than said law 
permitted the corporation to provide prior to such amendment), against all 
expense, liability and loss (including attorneys' fees, 
 
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judgments, fines, ERISA excise taxes or penalties and amounts paid or to be 
paid in settlement) reasonably incurred or suffered by such person in 
connection therewith and such indemnification shall continue as to a person 
who has ceased to be a director, officer, employee or agent and shall inure 
to the benefit of his or her heirs, executors and administrators; provided, 
however, that, except as provided in the second paragraph hereof, the 
corporation shall indemnify any such person seeking indemnification in 
connection with a proceeding (or part thereof) initiated by such person only 
if such proceeding (or part thereof) was authorized by the Board of Directors 
of the corporation. The right to indemnification conferred in this section 
shall be a contract right and shall include the right to be paid by the 
corporation for any expenses incurred in defending any such proceeding in 
advance of its final disposition; provided, however, that, if the Delaware 
General Corporation Law requires, the payment of such expenses incurred by a 
director or officer in his or her capacity as a director or officer (and not 
in any other capacity in which service was or is rendered by such person 
while a director or officer, including, without limitation, service to an 
employee benefit plan) in advance of the final disposition of a proceeding, 
shall be made only upon delivery to the corporation of an undertaking, by or 
on behalf of such director or officer, to repay all amounts so advanced if it 
shall ultimately be determined that such director or officer is not entitled 
to be indemnified under this section or otherwise. The corporation may, by 
action of its Board of Directors, provide indemnification to employees and 
agents of the corporation with the same scope and effect as the foregoing 
indemnification of directors and officers.
 
         If a claim under the first paragraph of this section is not paid in 
full by the corporation within thirty (30) days after a written claim has 
been received by the corporation, the claimant may at any time thereafter 
bring suit against the corporation to recover the unpaid amount of the claim 
and, if successful in whole or in part, the claimant shall be entitled to be 
paid also the expense of prosecuting such claim. It shall be a defense to any 
such action (other than an action brought to enforce a claim for expenses 
incurred in defending any proceeding in advance of its final disposition 
where the required undertaking, if any is required, has been tendered to the 
corporation) that the claimant has not met the standards of conduct which 
make it permissible under the Delaware General Corporation Law for the 
corporation to indemnify the claimant for the amount claimed, but the burden 
of proving such defense shall be on the corporation. Neither the failure of 
the corporation (including its Board of Directors, independent legal counsel, 
or its stockholders) to have made a determination prior to the commencement 
of such action that indemnification of the claimant is proper in the 
circumstances because he or she has met the applicable standard of conduct 
set forth in the Delaware General Corporation Law, nor an actual 
determination by the corporation (including its Board of Directors, 
independent legal counsel, or its stockholders) that the claimant has not met 
such applicable standard of conduct, shall be a defense to the action or 
create a presumption that the claimant has not met the applicable standard of 
conduct.
 
         The right to indemnification and the payment of expenses incurred in 
defending a proceeding in advance of its final disposition conferred in this 
section shall not be exclusive of any other right which any person may have 
or hereafter acquire under any statute, provision of the Restated Certificate 
of Incorporation, by-law, agreement, vote of stockholders or disinterested 
directors or otherwise.
 
         C.   INSURANCE. The corporation may maintain insurance, at its 
expense, to protect itself and any director, officer, employee or agent of 
the corporation or another corporation, partnership, joint venture, trust or 
other enterprise against any such expense, liability or loss, whether or not 
the 
 
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corporation would have the power to indemnify such person against such 
expense, liability or loss under the Delaware General Corporation Law.
 
         D.   REPEAL AND MODIFICATION. Any repeal or modification of the 
foregoing provisions of this Article XI shall not adversely affect any right 
or protection of any director, officer, employee or agent of the corporation 
existing at the time of such repeal or modification.
 
 
                                   ARTICLE XII
 
         The corporation reserves the right to amend or repeal any provision 
contained in this Restated Certificate of Incorporation, in the manner now or 
hereafter prescribed by statute, and all rights conferred upon a stockholder 
herein are granted subject to this reservation.
 
 
                                  ARTICLE XIII
 
         Notwithstanding any other provision of this Restated Certificate of 
Incorporation, the affirmative vote of the holders of at least sixty-six and 
two-thirds percent (66-2/3%) of the voting power of all of the then 
outstanding shares of the stock of the corporation entitled to vote generally 
in the election of directors, voting together as a single class, shall be 
required to amend in any respect or repeal this Article XIII, or Articles VI, 
VII, VIII and XI.
 
                                    * * * * *
 
                  Four: This Restated Certificate of Incorporation was duly
         adopted by the Board of Directors of this corporation.
 
                  Five: This Restated Certificate of Incorporation was duly
         adopted by written consent of the stockholders of the corporation in
         accordance with Sections 228, 242 and 245 of the General Corporation
         Law of the State of Delaware and written notice of such action has been
         given as provided in Section 228.
 
         IN WITNESS WHEREOF, Nanogen, Inc. has caused this certificate to be 
signed by the undersigned officer, thereunto duly authorized, this 17th day 
of April 1998.
 
 
 
 
                                        By:     /s/ Harry J. Leonhardt, Esq
                                           ----------------------------------
                                                 Harry J. Leonhardt, Esq.
                                             Vice President, General Counsel
                                                      and Secretary