<PAGE>

                                                                  EXHIBIT 10.34

[CONFIDENTIAL TREATMENT REQUESTED.  CONFIDENTIAL PORTIONS OF THIS AGREEMENT HAVE
BEEN REDACTED AND HAVE BEEN SEPARATELY FILED WITH THE COMMISSION]









                   COLLABORATIVE RESEARCH AND DEVELOPMENT AGREEMENT




                                    By and Between



                HOECHST RESEARCH & TECHNOLOGY DEUTSCHLAND GMBH & CO KG



                                         and



                                    NANOGEN, INC.








                                   December 3, 1998

<PAGE>

                                  TABLE OF CONTENTS

<TABLE>
<CAPTION>

                                                                                 Page
                                                                                 ----
<S>                                                                              <C>
1.   Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

2.   Research Program. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

3.   Payment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

4.   Reports and Records . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

5.   Confidentiality and Non-disclosure. . . . . . . . . . . . . . . . . . . . . . 10

6.   Intellectual Property Licenses. . . . . . . . . . . . . . . . . . . . . . . . 10

7.   Intellectual Property and Patent Rights . . . . . . . . . . . . . . . . . . . 11

8.   Term and Termination. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

9.   Representations and Warranties. . . . . . . . . . . . . . . . . . . . . . . . 14

10.  Disclaimers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

11.  Insurance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

12.  Notices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

13.  Dispute Resolution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

14.  Miscellaneous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

</TABLE>

EXHIBITS

Exhibit A      HR&T Patent Applications
Exhibit B      Nanogen Patent Applications
Exhibit C      Annual Budget
Exhibit D      Program Inventions
Exhibit E      Research Program
Exhibit F      CPR Procedures


                                     -i-
<PAGE>

                COLLABORATIVE RESEARCH AND DEVELOPMENT AGREEMENT


     THIS COLLABORATIVE RESEARCH AND DEVELOPMENT AGREEMENT is dated as of 
December 3, 1998 by and between HOECHST RESEARCH & TECHNOLOGY DEUTSCHLAND 
GMBH & CO KG, a German company, having a place of business at D-65926 
Frankfurt am Main, Germany (hereinafter, "HR&T"), and NANOGEN, INC., a 
Delaware corporation, having its principal office and place of business at 
10398 Pacific Center Court, San Diego, California 92121 (hereinafter, 
"Nanogen").

                                W I T N E S S E T H :

     WHEREAS, Nanogen has developed certain technology related to 
electronically addressable microchip oligonucleotide arrays ("Arrays"), 
including Nanogen's Automated Programmable Electronic Matrix ("APEX") 
technology; and

     WHEREAS, HR&T has developed certain technology related to combinatorial 
and/or modular nanotechnology, including its Exponential Library by 
Association of Sublibraries ("ELIAS") and its pRNA (and related 
oligonucleotide analog) technology; and

     WHEREAS, HR&T and Nanogen have previously entered into a Letter 
Agreement dated December 4, 1997 (the "Letter Agreement"); and

     WHEREAS, in accordance with the terms of the Letter Agreement (including 
the paragraphs under the headings "Purpose of Collaboration" and "Agreement 
Field"), HR&T and Nanogen wish to perform certain research and development 
activities as contemplated therein.

     NOW THEREFORE, in consideration of the mutual covenants and undertakings 
contained herein, the parties hereby agree as follows:

     1.     DEFINITIONS.  As used in this Agreement:

     1.1    "Agreement" shall mean this Agreement and any exhibits, 
appendices, attachments or addenda hereto, and any renewals or extensions of 
this Agreement.

     1.2    "HR&T Intellectual Property" shall mean and include all 
patentable and unpatentable inventions, ideas, discoveries, improvements, 
design rights, semiconductor mask works, works of authorship, trade secrets, 
know-how and any equivalents thereof which are in existence as of the 
Effective Date or thereafter, as are necessary to make, have made, use or 
sell a Product and are owned by HR&T, including, but not limited to, HR&T's 
ELIAS and pRNA technologies disclosed in the HR&T patent applications set 
forth in Exhibit A hereto (amended with each new HR&T patent application 
necessary to make, have made, use or sell a Product).

                                     -1-
<PAGE>

     1.3    "HR&T Patent Rights" shall mean all patents and patent 
applications owned by HR&T which are in existence as of the Effective Date or 
thereafter, including the patent applications set forth in Exhibit A hereto 
(amended with each new HR&T patent application necessary to make, have made, 
use or sell a Product), and which contain a claim necessary to make, have 
made, use or sell a Product, including all divisionals, continuations, 
continuations-in-part, re-examinations, reissues, and all foreign equivalents 
of any of the foregoing in whole or in part.

     1.4    "HR&T Program Inventions" shall mean all Program Inventions made 
or conceived by employees or others acting solely on behalf of HR&T;  
PROVIDED, however, that HR&T Program Inventions shall not include Program 
Inventions which utilize both APEX and ELIAS and/or pRNA technology.

     1.5    "Effective Date" shall mean January 1, 1998.

     1.6    "Executive Committee" shall mean a committee which shall (i) be 
responsible for overseeing the Research Management Committee, (ii) set 
strategic goals under this Agreement and the Letter Agreement, (iii) approve 
annual budgets for the Research Program (the annual budget for the first year 
and a proposed annual budget for the second year of the Research Program are 
set forth in Exhibit C hereto), (iv) set research milestones and (v) decide 
when milestones have been completed.  The Executive Committee shall consist 
of three (3) members appointed by Nanogen and three (3) members appointed by 
HR&T.  All decisions of the Executive Committee must be by unanimous consent 
of all members of the Executive Committee.

     1.7    "Joint Program Inventions" shall mean (i) all Program Inventions 
made or conceived by employees or others acting on behalf of HR&T jointly 
with employees or others acting on behalf of Nanogen and (ii) all Program 
Inventions which utilize both APEX and ELIAS and/or pRNA technology.

     1.8    "Nanogen Intellectual Property" shall mean and include all 
patentable and unpatentable inventions, ideas, discoveries, improvements, 
design rights, semiconductor mask works, works of authorship, trade secrets, 
know-how and any equivalents thereof which are in existence as of the 
Effective Date or thereafter, are necessary to make, have made, use or sell a 
Product and are owned  by Nanogen, including, but not limited to, Nanogen's 
APEX technology disclosed in the Nanogen patents and patent applications set 
forth in Exhibit B hereto (amended with each new patent application necessary 
to make, have made, use or sell a Product).

     1.9    "Nanogen Patent Rights" shall mean all patents and patent 
applications owned by Nanogen which are in existence as of the Effective Date 
or thereafter, including the patents and patent applications set forth in 
Exhibit B hereto (amended with each new patent application necessary to make, 
have made, use or sell a Product), and which contain a claim necessary to 
make, have made, use or sell a Product, including all divisionals, 
continuations, continuations-in-part, re-examinations, reissues, and all 
foreign equivalents of any of the foregoing in whole or in part.

                                     -2-
<PAGE>

     1.10   "Nanogen Program Inventions" shall mean all Program Inventions 
made or conceived by employees or others acting solely on behalf of Nanogen; 
PROVIDED, however, that Nanogen Program Inventions shall not include Program 
Inventions which utilize both APEX and ELIAS and/or pRNA technology.

     1.11   "Primary Filing Countries" shall mean the United States, Canada, 
European Community Countries and Japan.

     1.12   "Products" shall mean products or applications utilizing jointly 
developed technology and incorporating both Nanogen's APEX technology as 
disclosed in Exhibit B hereto and HR&T's ELIAS and/or pRNA technology as 
disclosed in Exhibit A hereto.

     1.13   "Program Inventions" shall mean and include all patentable and 
unpatentable inventions, ideas, discoveries, improvements, design rights, 
semiconductor mask works, works of authorship, trade secrets, know-how and 
any equivalents thereof, and any patent applications or patents based 
thereon, made or conceived during and as a result of the Research Program, 
all of which shall be identified in Exhibit D to this Agreement, which 
Exhibit shall be amended from time to time as warranted.

     1.14(a)  "Reimbursable Costs" shall mean all direct and indirect costs 
incurred by Nanogen in performing its obligations under this Agreement, which 
may include without limitation, as applicable:

            (i)  salaries and wages,

            (ii)  payroll taxes,

            (iii)  contract labor,

            (iv)  fringe benefits,

            (v)  expenses incurred in occupying facilities (including
     leasehold improvements) and equipment-related expenses, excluding
     depreciation and amortization expenses,

            (vi)  recruitment and relocation,

            (vii)  communications expense,

            (viii)  supplies,

            (ix)  development and prototype materials,

            (x)  freight and transportation,

            (xi)  training and education,

                                     -3-
<PAGE>

            (xii)  travel expenses,

            (xiii)  data processing costs,

            (xiv)  patent, trademark and license fees and filing,
     prosecution and maintenance expenses for Nanogen Intellectual Property
     as set forth in Exhibit B,

            (xv)  insurance,

            (xvi)  professional services,

            (xvii)  depreciation and amortization of facilities (including
     leasehold improvements) and equipment,

            (xviii)  a financing charge for capital acquisitions made by
     Nanogen for use in performing work under this Agreement,

            (xix)  outside purchased services,

            (xx)  sales and use taxes (including such taxes applicable to
     the acquisition, use, transfer or deemed transfer of property),

            (xxi)  periodic lease and rental payments under capital or
     financing leases,

            (xxii)  costs of applying for regulatory approvals on Products
     approved by the Executive Committee, and fees payable to governmental
     agencies, including the United States Food and Drug Administration
     (the "FDA") and comparable foreign regulatory authorities, including
     expenses resulting from generation of chemical, toxicological,
     microbiological and pharmacological data and techniques, clinical data
     and product formulations and specifications, and

            (xxiii)  periodic and special reports, including reports to
     the Research Management Committee.

     (b)    In determining Reimbursable Costs, Nanogen will employ the 
following accounting policies:

            (i)  General use capital equipment, facilities and leasehold
     improvements will be assigned an estimated economic useful life and
     salvage value, if any, and depreciation and amortization will be
     computed using the straight-line method.  Depreciation and
     amortization will be allocated to Reimbursable Costs under this
     Agreement directly or through overhead rates applied to direct head
     count.

                                     -4-
<PAGE>

            (ii)  Such capital equipment purchased pursuant to agreement
     between both parties for use in connection with this Agreement will be
     charged directly against the budget in the quarter the expense was
     incurred.

            (iii)   Total facilities expenses of Nanogen, excluding
     leasehold improvement amortization allocated to specific functional
     areas and net of any sublease revenues, will be allocated to
     Reimbursable Costs under this Agreement based on the ratio of direct
     personnel engaged in work under this Agreement to the total Nanogen
     head count.

            (iv)  General and administrative expenses of Nanogen will be
     allocated to this Agreement directly or based on the ratio of total
     Reimbursable Costs to total operating expenses of Nanogen, excluding
     (in both instances) general and administrative expenses subject to
     such allocation, as agreed between the Controllers of both parties.

            (v)  All other indirect expenses not covered in Paragraphs (i)
     through (iv) of this Paragraph 1.14(b) which are in support of the
     Research Program will be allocated to Reimbursable Costs under this
     Agreement through overhead rates applied to Nanogen direct head count,
     as agreed between the Controllers of both parties.

            (vi)  Notwithstanding the foregoing, for purposes of this
     Agreement, Reimbursable Costs shall not include direct and indirect
     costs for start-up of commercial manufacturing, installation of
     commercial production lines and commercial product manufacturing
     operations.  These costs shall be addressed in connection with the
     contemplated joint venture agreement between the parties.

     (c)    The term "capital acquisition" as used herein shall mean that 
portion of capital equipment, facilities, leasehold improvements or other 
property, whenever acquired by Nanogen, which are capitalized on Nanogen's 
accounting records and which are either:  (i) purchased directly by Nanogen; 
(ii) financed by Nanogen under a conditional sale contract; (iii) financed by 
Nanogen through a secured loan; or (iv) assets constructed in-house by 
Nanogen. Assets acquired under capital or financing leases will not be 
considered capital acquisitions for purposes of this Paragraph.

     (d)    With respect to capital acquisitions financed by Nanogen with 
specific borrowing, the financing charge referred to above will be in the 
amount and at the time of the actual financing costs incurred by Nanogen.  
With respect to capital acquisitions not financed by Nanogen with specific 
borrowing, the financing charge will be based on the prime lending rate in 
effect from time to time at Citibank N.A., New York, New York, plus two (2) 
percentage points, to the extent permitted by applicable law, applied to 
Nanogen's net book value. "Net book value" is defined as the gross capital 
acquisition value excluding capital acquisitions financed by Nanogen with 
specific borrowing, less related accumulated depreciation and amortization.  
The financing charge for each billing period will be prorated 

                                     -5-
<PAGE>

to the extent depreciation or amortization of the capital acquisitions has 
been allocated to work other than work under this Agreement during such 
period.  The financing charge will be calculated monthly based on the net 
book value at the end of the preceding fiscal month.

     1.15   "Research Management Committee" shall mean a committee which 
shall be responsible for preparing the Research Program and supervising, 
managing and monitoring the progress of the Research Program, for conducting 
marketing studies and for facilitating the open exchange of information 
between the parties.  The Research Management Committee shall consist of two 
(2) employees of HR&T and two (2) employees of Nanogen, at least one of whom 
from each company shall be at the research director level (or equivalent) or 
higher.  Decisions that are not taken unanimously by the Research Management 
Committee are to be referred to the Executive Committee for resolution.

     1.16   "Research Program" shall mean the cumulative endeavors of the 
parties to produce Products in accordance with the specifications, 
timetables, milestones, reports and deliverables, as set forth in Exhibit E 
hereto, as it may be amended from time to time.  The Research Program shall 
be divided into two phases, the "Research Phase", which shall mean all 
research activities up to and including the development of a prototype and 
the "Product Development Phase, which shall mean all post-prototype 
development activities relating to the development of Products, for 
commercialization."

     2.     RESEARCH PROGRAM.

     2.1    Each of HR&T and Nanogen shall use reasonable efforts to perform 
their respective activities in accordance with the Research Program.  Subject 
to the terms and conditions of this Agreement, HR&T and Nanogen are free to 
independently develop, market and sell any products other than Products.

     2.2    Each of HR&T and Nanogen shall promptly notify the other party, 
in writing, through the Research Management Committee, of the existence of 
any new Program Inventions.

     2.3    The Research Management Committee shall meet from time to time, 
but at least once every three (3) months during the term of this Agreement, 
alternating between the headquarters of HR&T and Nanogen or at a mutually 
agreed location, to:  (a) review progress and ongoing resource allocation and 
budgeting matters of the Research Program; (b) amend the Research Program as 
agreed by the parties; (c) disclose Program Inventions which have not 
previously been disclosed in accordance with Paragraph 2.2; and (d) review 
the status of patent filings with respect to Program Inventions and, if 
necessary in view of such review, propose amendments to Appendix A of this 
Agreement.  All decisions taken by the Research Management Committee must be 
by unanimous consent of all the members of the Research Management Committee. 
In order to facilitate the disclosure of Program Inventions and the review 
of the status of patent filings with respect to Program Inventions, patent 
attorneys for HR&T and Nanogen may participate in all such meetings.

                                     -6-
<PAGE>

     2.4    Within five (5) business days following each meeting pursuant to 
Paragraph 2.3, the Research Management Committee shall cause to be prepared a 
written summary of such meeting, which summary shall include, at a minimum:  
(a) a list of all Program Inventions which have come into existence since the 
Effective Date or since the previous meeting, whichever is applicable; (b) 
all patent filings with respect to Program Inventions since the Effective 
Date or since the previous meeting, whichever is applicable; and (c) a report 
regarding the progress of the Research Program, which shall include the 
tracking of the Research Program to budget and a report on any material 
budgetary implications for changes to the Research Program.  Such written 
summary shall be provided to the Executive Committee.

     2.5    The Executive Committee shall meet from time to time, but at 
least once every three (3) months during the term of this Agreement, 
alternating between the headquarters of HR&T and Nanogen, a mutually agreed 
location or by telephonic or video conference, to:  (a) receive a report on 
the progress of the Research Program by the Research Management Committee; 
(b) review the strategic goals pursuant to the Letter Agreement and this 
Agreement; (c) approve annual budgets under the Research Program and review 
the progress of the Research Program against the budget; (d) establish, 
review and revise milestones where appropriate, and (e) determine the level 
of progress toward achievement of milestones and determine milestone 
completion.  Within five (5) business days after each meeting, the Executive 
Committee shall cause minutes to be prepared and distributed to each party 
accurately documenting such meeting.

     2.6    Nanogen and HR&T may, upon reasonable notice during normal 
business hours, (a) consult informally, during such visits and by telephone, 
with personnel of the other party performing work on the Research Program, 
and (b) with the other party's prior approval, which approval shall not be 
unreasonably withheld, visit the sites of any tests or experiments being 
conducted by such other party in connection with the Research Program, but 
only to the extent in each case as such trials or other experiments relate to 
the Research Program.  On such visits an employee of the host company 
conducting the research or development activities shall accompany the 
employee(s) of the visiting party.  If requested by the visiting party, the 
other party shall cause appropriate individuals working on the Research 
Program to be available for meetings at the location of the facilities where 
such individuals are employed at times reasonably convenient to the party 
responding to such request.  All information revealed to representatives of 
the HR&T and Nanogen during the visits and consultations provided for in this 
Paragraph 2.5 shall be treated as confidential information in accordance with 
Paragraph 5 of this Agreement.

     3.     PAYMENT.

     3.1    HR&T shall pay *** of its own research and development costs and
shall pay *** of Nanogen's Reimbursable Costs incurred in performing its
obligations under this Agreement (the "Fee").  Nanogen's Reimbursable Costs
shall not exceed *** per year per full time equivalent researchers and staff
assigned to the Research Program.  Neither party makes any warranty that these


--------------------------------
***    Confidential material redacted and separately filed with the Commission.

                                     -7-
<PAGE>

costs and fees will be sufficient to complete the Research Program.  The Fee 
shall be payable by HR&T to Nanogen as follows:

     (a)  The initial annual budget and a proposed budget for the second year 
of the Research Program are attached as Exhibit C.  Annually thereafter 
during the term hereof, the Research Management Committee shall develop a 
budget for the Research Program, including anticipated quarterly expenditures 
by each party.  The Research Management Committee shall submit each such 
subsequent budget to the Executive Committee for its review and approval at 
least forty-five (45) days prior to commencement of the next annual period.  
The Executive Committee shall review such budget and inform the Research 
Management Committee of its determination with respect to same within thirty 
(30) days following its receipt of same.  If the budget is not approved, the 
Research Management Committee shall confer with the Executive Committee to 
attempt to develop a mutually acceptable budget.  If the Executive Committee 
cannot resolve the dispute, then such dispute shall be resolved in accordance 
with the provisions of Paragraph 13 hereof.

     (b)  The Fee shall be payable to Nanogen in quarterly installments 
commencing on January 1, 1998.  Each quarterly installment shall be due not 
later than five (5) business days following the first day of each quarter. 
Should a major positive balance arise due to underuse of the budget, this 
will be balanced with the fourth quarter payment in each year.  All 
installments shall be based upon an estimate of the Reimbursable Costs 
expected to be incurred by Nanogen during its next quarterly period beginning 
on such date, up to a maximum of Nanogen's budgeted amount for such quarter.  
Such estimate shall be set forth in an invoice prepared by Nanogen in 
reasonable detail, signed by a duly authorized officer of Nanogen and 
submitted to the Research Management Committee at least twenty (20) days 
prior to the beginning of the quarterly period with respect to which such 
payment is to be made.  Each such invoice shall be due and payable in full by 
HR&T prior to the beginning of such quarterly period.  Beginning with the 
second invoice under this Agreement, such invoice shall include a 
reconciliation and adjustment for the period covered by the preceding invoice 
to reflect any difference between actual Reimbursable Costs incurred by 
Nanogen and estimated Reimbursable Costs for such period, up to a maximum of 
Nanogen's budgeted amount for such quarter.  Any amounts in excess of the 
budgeted amount shall be subject to the review and approval of the Executive 
Committee.

     3.2  If HR&T fails to make prompt and timely payment, Nanogen may give 
written notice thereof, and unless HR&T within fifteen (15) days following 
receipt of such notice makes such payment, Nanogen may at any time thereafter 
until HR&T makes such payment suspend the research and development services 
under this Agreement on written notice to HR&T.

     3.3  In the event Nanogen, in course of its research under this 
Agreement, is required to lease equipment which Nanogen would ordinarily not 
otherwise be required to lease, and HR&T agrees to such lease, HR&T will be 
responsible for such lease payments.

                                     -8-
<PAGE>

     4.   REPORTS AND RECORDS.

     4.1  Nanogen and HR&T shall provide to the Research Management Committee 
within forty-five (45) days following the end of each quarterly period 
beginning with the end of the first period on March 31, 1998, a report in 
such reasonable detail as the Research Management Committee may request 
setting forth:

     (a)  the Reimbursable Costs incurred by Nanogen and the costs incurred 
by HR&T in performing its obligations under the Research Program during such 
period;

     (b)  the work performed by such party during such period; and

     (c)  the status of the research and development of the Products at the 
end of the period.

     4.2  Nanogen shall keep and maintain, in accordance with generally 
accepted accounting principles and practices, proper and complete records and 
books of account documenting all Reimbursable Costs.  Each party agrees to 
permit either nationally recognized certified public accountants or 
Controllers from the other party to verify on a once annually basis the 
Reimbursable Costs or costs billed or incurred pursuant to this Agreement; 
and Nanogen shall provide annually a certification by nationally recognized 
certified public accountants or its internal Controller as to Reimbursable 
Costs billed to HR&T in that year.  HR&T will keep confidential, and will not 
disclose to any third party, except such disclosures as may be required by 
law, without the prior written consent of Nanogen, information in statements 
delivered to HR&T or obtained by HR&T through access of its independent 
certified public accounting firm or Controller to the books and records of 
Nanogen.  HR&T shall provide similar access and similar certifications to 
Nanogen regarding its costs incurred under the Research Program and Nanogen 
shall similarly keep such information confidential.

     5.   CONFIDENTIALITY AND NON-DISCLOSURE.  That certain Mutual 
Confidential Disclosure Agreement effective as of February 20, 1997 between 
HR&T and Nanogen, as amended (the "Confidentiality Agreement"), shall remain 
in full force and effect.

     6.   INTELLECTUAL PROPERTY LICENSES.

     6.1  (a)  HR&T hereby grants solely during the term of this Agreement to 
Nanogen, a worldwide, royalty-free, nonexclusive license in and to HR&T 
Intellectual Property and HR&T Patent Rights, solely to use in research and 
development activities pursuant to the Research Program under this Agreement.

     (b)  HR&T recognizes that Nanogen has conducted considerable research 
and development activities in connection with its permeation layer technology 
and has protected certain of its advancements with intellectual property.  
HR&T is willing, as part of this Agreement, to conduct additional research 
activities directed toward Nanogen's permeation layer.  To the extent HR&T 
invents any new inventions or any improvements to Nanogen's inventions 
relating to permeation layers with utility on Nanogen's Arrays which would

                                     -9-
<PAGE>

constitute HR&T Intellectual Property or HR&T Patent Rights or HR&T Program 
Inventions, HR&T will grant to Nanogen a worldwide, royalty-free license to 
practice such intellectual property (without the right to sublicense unless 
it applies to a Nanogen product).  Nanogen will be licensed to practice such 
intellectual property in connection with any of its other joint venture 
arrangements or corporate collaborations subject to a 2% of net sales royalty 
payable to any joint venture or other joint relationship involving Nanogen 
and HR&T.

     (c)  Nanogen hereby grants solely during the term of this Agreement, to 
HR&T, a worldwide, royalty-free, nonexclusive license in and to Nanogen 
Intellectual Property and Nanogen Patent Rights, solely to use in research 
and development activities pursuant to the Research Program under this 
Agreement.

     6.2  Except as provided therein, the licenses granted in accordance with 
Paragraphs 6.1(a) and (b) do not include a right to grant sublicenses.

     6.3  In the event that any substantial and continuing infringement of 
any of the HR&T Patent Rights or Nanogen Patent Rights licensed hereunder 
comes to the attention of either party hereto, such party shall promptly 
notify the Executive Committee, which Committee will determine an appropriate 
action in accordance with its authority.

     7.   INTELLECTUAL PROPERTY AND PATENT RIGHTS.

     7.1  During the term of this Agreement, the entire right, title and 
interest in all Program Inventions shall be owned jointly by HR&T and Nanogen 
and may be used only as they mutually agree.

     7.2  Each party hereto promptly shall disclose to the other party the 
making, conception or reduction to practice of Program Inventions by 
employees or others acting on behalf of such party.  Each of Nanogen and HR&T 
hereby represents and warrants that all employees and others acting on its 
respective behalf in performing its obligations under this Agreement shall be 
obligated under a binding written agreement to assign to it, or as it shall 
direct, all Program Inventions made or developed by such employees or others.

     7.3  Promptly following any disclosure of Program Inventions pursuant to 
Paragraph 2.2 and Paragraph 7.2, the Research Management Committee, in 
consultation with patent attorneys for HR&T and Nanogen, shall discuss and 
determine, in good faith, whether patent applications should be prepared and 
filed for such disclosed Program Inventions.

     7.4  If patent applications are to be prepared and filed pursuant to 
Paragraph 7.3, then the Research Management Committee shall discuss and 
determine, in good faith, for each of such Program Inventions, which of the 
parties shall be responsible for the preparation, filing, prosecution and 
maintenance of such patent applications in the Primary Filing Countries.  
Each of such patent applications shall become part of the Program Inventions, 
and Exhibit D shall be amended accordingly to evidence such Program 
Inventions.

                                     -10-
<PAGE>

     7.5  (a)  If the Research Management Committee determines that a 
particular patent application be filed in a country or countries in addition 
to the Primary Filing Countries, then the Research Management Committee shall 
determine which party shall be responsible for the filing, prosecution and 
maintenance of such patent application, and such patent application shall be 
part of the Program Inventions.

     (b)  If the Research Management Committee determines not to file a 
particular patent application in a country or countries in addition to the 
Primary Filing Countries, either party, alone, after written waiver by the 
other party, may file such particular patent application in such country or 
countries and shall pay, without right to reimbursement thereof, all costs 
and expenses for filing, prosecution and maintenance of patent application 
filed in such country or countries, and notwithstanding the provisions of 
Paragraph 6.1, that party shall own, exclusively, all right, title and 
interest in such patent application.

     (c)  If the other party of Paragraph 7.5(b) does not provide such 
written waiver, then any such particular patent application shall be treated 
as if the Research Management Committee had made a declaration to file the 
particular patent application in a country or countries in addition to the 
Primary Filing Countries in accordance with Paragraph 7.5(a).

     7.6  Each party shall keep the Research Management Committee currently 
informed of the filing and progress of all material aspects of the 
prosecution of all such patent applications and of the issuance of patents, 
and shall consult with the Research Management Committee concerning any 
decisions which would affect the scope of any issued claims and other 
prosecutorial details, including the potential abandonment of any application.

     7.7  Upon request, each party shall execute and deliver to the other 
party all descriptions, applications, assignments and other documents and 
instruments as are necessary or proper to carry out the provisions of 
Paragraphs 7.1, 7.2, 7.3, 7.4, 7.5 and 7.6 without further compensation, 
except as otherwise provided in Paragraph 1.15, and the parties shall 
cooperate with and assist each other or their nominees in all reasonable ways 
and at all reasonable times, including, but not limited to, testifying in all 
legal proceedings, signing all lawful papers and in general performing all 
lawful acts reasonable, necessary or proper, to aid the other party in 
obtaining, maintaining, defending and enforcing all lawful patent, copyright, 
trade secret, know-how and the like in the Primary Filing Countries and 
elsewhere.

     7.8  Except as otherwise provided in this Agreement, under no 
circumstances shall either party, as a result of this Agreement, obtain any 
ownership interest or other right in any technology, know-how, trade secrets, 
patents, pending patent applications or products of the other party, 
including items owned, controlled or developed by the other, or transferred 
by the other to such party at any time pursuant to this Agreement.  Upon 
termination of this Agreement unless otherwise provided in another agreement 
between HR&T and Nanogen, (i) all HR&T Program Inventions, Nanogen Program 
Inventions and Joint Program Inventions, which consist solely of improvements 
to HR&T Intellectual Property, shall be the sole property of HR&T, (ii) all 
Nanogen Program Inventions, HR&T Program Inventions and Joint Program 
Inventions, which consist solely of improvements to Nanogen Intellectual 
Property, shall be the sole property of Nanogen, and (iii) Nanogen, at its 
option, shall have the right for

                                     -11-
<PAGE>

120 days after the date of termination of this Agreement to negotiate with 
HR&T to enter into a license for HR&T's rights to any Program Invention not 
included within the provisions of clause (i) or (ii) above.  If Nanogen 
chooses to exercise such option, HR&T and Nanogen shall negotiate in good 
faith to enter into a license for such Program Invention or Inventions.  Any 
such license shall provide that Nanogen will pay a reasonable royalty to HR&T 
for the license rights to such Program Invention or Inventions.  In 
determining what is a reasonable royalty rate, HR&T's relative contribution 
to such Program Invention or Inventions shall be taken into account.  It is 
understood and agreed by the parties hereto that this Agreement does not 
grant to either party any license or other right, other than the licenses 
granted in Paragraph 6.1, the assignments granted in Paragraph 7.1 and the 
licenses granted in this Paragraph 7.8.

     7.9  (a)  During the term of this Agreement, Nanogen and HR&T each 
acknowledge each other's interest in publishing certain of its results to 
obtain recognition within the scientific community and to advance the state 
of scientific knowledge.  Each party also recognizes the mutual interest in 
obtaining valid patent protection and protecting business interests. 
Consequently, each party, its employees or consultants wishing to make a 
publication (including any oral disclosure made without obligation of 
confidentiality) relating to work performed by such party as part of the 
Research Program (the "Publishing Party") shall transmit to the Research 
Management Committee a copy of the proposed written publication at least 
forty-five (45) days prior to submission for publication, or an outline of 
such oral disclosure at least fifteen (15) days prior to presentation.  The 
Research Management Committee shall have the right (i) to propose 
modifications to the publication for patent reasons and (ii) to request a 
reasonable delay in publication in order to protect patentable information.

     (b)  If the Research Management Committee requests such a delay, the 
Publishing Party shall delay submission or presentation of the publication 
for a period of ninety (90) days to enable patent applications protecting 
each party's rights in such information to be filed in accordance with this 
Article 7.  Upon the expiration of forty-five (45) days, in the case of 
proposed written disclosures, or fifteen (15) days, in the case of proposed 
oral disclosures, from transmission to the Research Management Committee, the 
Publishing Party shall be free to proceed with the written publication or the 
presentation, respectively, unless the Research Management Committee has 
requested the delay described above.

     8.   TERM AND TERMINATION.

     8.1  The Research and Development Collaboration between Nanogen and HR&T 
shall continue on its terms for a guaranteed period of three (3) years from 
its effective date of January 1, 1998.

                                     -12-
<PAGE>

     8.2  All records required to be maintained pursuant to Paragraph 4.2 
shall be retained for a period of at least five (5) years following the 
termination of this Agreement.

     9.   REPRESENTATIONS AND WARRANTIES.

     9.1  HR&T hereby represents and warrants to Nanogen that it has full 
authority and power to enter into this Agreement, that it has secured any and 
all necessary approvals, permits or consents deemed necessary or advisable 
for the consummation of the transactions contemplated hereby and that, upon 
execution by HR&T and Nanogen, this Agreement shall immediately be a valid 
and binding obligation of HR&T, enforceable in accordance with its terms.

     9.2  Nanogen hereby represents and warrants to HR&T that it has full 
authority and power to enter into this Agreement, that it has secured any and 
all necessary approvals, permits or consents deemed necessary or advisable 
for the consummation of the transactions contemplated hereby and that, upon 
execution by HR&T and Nanogen, this Agreement shall immediately be a valid 
and binding obligation of Nanogen enforceable in accordance with its 

                                     -13-
<PAGE>

terms and that the execution, delivery and performance of its obligations 
under this Agreement will not cause Nanogen to breach or violate any 
agreement between Nanogen and Becton, Dickinson and Company and its 
affiliated entities.

     9.3  HR&T hereby represents and warrants to Nanogen that:  (a) it is the 
owner of the entire right, title and interest to the HR&T Intellectual 
Property and HR&T Patent Rights, and (b) to HR&T's knowledge, the HR&T Patent 
Rights or the HR&T Intellectual Property has not infringed, and is not now 
infringing, any valid third party rights and HR&T has not received any notice 
of infringement from any third party respecting the HR&T Patent Rights or the 
HR&T Intellectual Property.

     9.4  Nanogen hereby represents and warrants to HR&T that:  (a) it is the 
owner of the entire right, title and interest to the Nanogen Intellectual 
Property and the Nanogen Patent Rights and (b) to Nanogen's knowledge, the 
Nanogen Patent Rights or the Nanogen Intellectual Property has not infringed, 
and is not now infringing, any valid third party rights and Nanogen has not 
received any notice of infringement from any third party respecting the 
Nanogen Patent Rights or the Nanogen Intellectual Property.

     10.  DISCLAIMERS.  THE PARTIES EACH HEREBY DISCLAIM ANY AND ALL 
REPRESENTATIONS AND WARRANTIES, EXPRESS OR IMPLIED, WITH RESPECT TO THEIR 
RESPECTIVE RESEARCH AND DEVELOPMENT EFFORTS HEREUNDER, INCLUDING, WITHOUT 
LIMITATION, (A) WHETHER ANY PRODUCT CAN BE SUCCESSFULLY DEVELOPED BY EITHER 
OF THE PARTIES, (B) WHETHER THE PRODUCTS AS DEVELOPED BY EITHER OF THE 
PARTIES HEREUNDER CAN BE COMMERCIALLY MARKETED, (C) THE ACCURACY, 
PERFORMANCE, UTILITY, RELIABILITY, TECHNOLOGICAL OR COMMERCIAL VALUE, 
COMPREHENSIVENESS, MERCHANTABILITY OR SUITABILITY FOR ANY PARTICULAR PURPOSE 
WHATSOEVER OF ANY PRODUCT, AND (D) WHETHER ANY PRODUCTS MANUFACTURED WILL NOT 
INFRINGE ANY THIRD-PARTY PATENT, COPYRIGHT OR SIMILAR RIGHT.

     11.  INSURANCE.  The parties shall each, at all times during the term of 
this Agreement, carry and maintain such insurance as each believes to be 
commercially reasonable against risks from actions contemplated under this 
Agreement.  Such insurance shall be with insurers of recognized 
responsibility and may be carried under blanket policies maintained by each 
of the parties.

     12.  NOTICES.  Any notice, request, demand, waiver, consent, approval, 
or other communication which is required or permitted hereunder shall be in 
writing and shall be deemed given only if delivered personally, by facsimile 
(upon receipt of appropriate written confirmation) or sent by registered or 
certified mail, return receipt requested, or by overnight courier service, 
postage prepaid as follows:

                                     -14-
<PAGE>

     If to Nanogen:

     Nanogen, Inc.
     10398 Pacific Center Court
     San Diego, California 92121
          Attn:  Chief Executive Officer
     Facsimile - (619) 546-7717

     with a copy to:

     Nanogen, Inc.
     10398 Pacific Center Court
     San Diego, California  92121
     Attn:  General Counsel
     Facsimile - (619) 546-7717

     and if to HR&T:

     Hoechst Research & Technology Deutschland GmbH & Co KG
     D-65926 Frankfurt am Main
     Attn:  President
     Facsimile - 001-49-69-309-588

     with a copy to:


or to such other address as the addressee may have specified in a notice duly 
given to the sender as provided herein.  Such notice, request, demand, 
waiver, consent, approval or other communication will be deemed to have been 
given as of the date so received (in case of personal delivery, facsimile or 
overnight courier service delivery) or upon refusal to accept delivery 
thereof.

     13.  DISPUTE RESOLUTION.  Every reasonable effort will be made by the 
parties hereto to resolve disputes arising hereunder with litigation as a 
last resort.  Any dispute arising out of or relating to this Agreement which 
is not resolved by the Executive Committee or is not within the purview of 
the Executive Committee shall be submitted to the Chief Executive Officer of 
Nanogen and the President of HR&T for resolution.  If those officers cannot 
resolve the dispute with twenty (20) days of submission of such dispute, then 
within ten (10) days thereafter, either party may, but shall not be obligated 
to, initiate nonbinding mediation of the controversy or claim under the 
Center for Public Resources Model ADR Procedures for Mediation of Business 
Disputes attached hereto as Exhibit F (the "CPR Procedures").  Once the 
mediation is initiated by one party, the other party agrees to participate in 
and conduct mediation in accordance with the CPR Procedures in good faith and 
not to pursue other remedies while such mediation is proceeding.  If neither 
party initiates mediation within ten (10) days of the officers referenced 
above failing to resolve the dispute, or if the dispute has not been resolved 
by such mediation within sixty (60) days following initiation of mediation,

                                     -15-
<PAGE>

either party may pursue all available remedies.  All applicable statutes of 
limitations and defenses based upon the passage of time shall be tolled while 
the negotiation and mediation procedures set forth in this Paragraph 13 are 
pending.  The parties will take such action, if any, as may be reasonably be 
required to effectuate such tolling.  Notwithstanding the foregoing, the 
remedy at law for any breach of the provisions of this Agreement may be 
inadequate, and, accordingly, an aggrieved party seeking equitable relief or 
remedies for such a breach shall have the right and is hereby granted the 
privilege, in addition to all other remedies at law or in equity, to proceed 
directly in a court of competent jurisdiction to seek temporary or 
preliminary equitable relief.  Each party shall pay its own costs incurred in 
attempting to resolve a dispute pursuant to the mediation procedures set 
forth in this Paragraph 13 without the right to recover such costs from the 
other party and shall share equally the cost of mediation.

     14.  MISCELLANEOUS.

     14.1 This Agreement and the Confidentiality Agreement together 
constitute the entire understanding among the parties with respect to the 
subject matter hereof and supersede and replace all prior agreements, 
understandings, writings and discussions between the parties relating to said 
subject matter.  However, it is the understanding of both parties that the 
terms laid down for a joint venture or other joint arrangement in the Letter 
Agreement shall survive until a definitive agreement for such an arrangement 
has been reached.

     14.2 This Agreement may be amended only by a written instrument executed 
by the parties hereto.  The failure of any party at any time or times to 
require performance of any provision hereof shall in no manner affect its 
rights at a later time to enforce the same.  No waiver by any party of any 
condition or term in any one or more instances shall be construed as a 
further or continuing waiver of such condition or term or any other condition 
or term.

     14.3 The terms and provisions contained in this Agreement are for the 
sole benefit of the parties and their successors and assigns, and they shall 
not be construed as conferring and are not intended to confer any rights on 
any other persons.

     14.4 Any delays in or failure of performance by any party under this 
Agreement shall not be considered a breach of this Agreement if and to the 
extent caused by occurrences beyond the reasonable control of the party 
affected, including but not limited to acts of God; acts, regulations, or 
laws of any government; strikes or other considered acts of workers; fires; 
floods; explosions; riots; wars; rebellion; and sabotage; and any time for 
performance hereunder shall be extended by the actual time of delay caused by 
such occurrence.

     14.5 This Agreement shall not be assignable by either party, nor shall 
any of its obligations hereunder be delegated to a third party, without the 
prior written consent of the other party, which consent shall not be 
unreasonably withheld or delayed.  In the event that the other party does not 
respond to a request from a party for consent to an assignment or delegation 
within fifteen (15) days following written notice requesting such consent, 
such party's shall be deemed to be granted.  In addition, a condition to any 
assignment or delegation hereunder shall be that the successor in interest 
expressly agrees in writing to

                                     -16-
<PAGE>

assume the assigning or delegating party's obligations hereunder.  All of the 
terms and provisions of this Agreement shall be binding upon and inure to the 
benefit of and be enforceable by the respective permitted successors and 
assigns.  No such assignment shall release the assigning party from its 
obligations hereunder.  Notwithstanding the foregoing, the consent of the 
other party shall not be required in connection with a merger involving 
either HR&T or Nanogen or with respect to an assignment of this Agreement in 
connection with, as the case may be, the acquisition, sale of all or 
substantially all of the assets of HR&T or Nanogen, or a change of control or 
similar transaction.

     14.6 If any provision(s) of this Agreement are or become invalid, or are 
ruled illegal by any court of competent jurisdiction, or are deemed 
unenforceable under then current applicable law from time to time in effect 
during the term hereof, it is the intention of the parties hereto that the 
remainder of this Agreement shall not be affected thereby.  It is further the 
intention of the parties that in lieu of each such provision which is 
invalid, illegal, or unenforceable, there be substituted or added as part of 
this Agreement, a provision which shall be as similar as possible in economic 
and business objectives as intended by the parties to such invalid, illegal, 
or unenforceable provision, but which shall be valid, legal, and enforceable, 
and shall be mutually agreed by the parties.

     14.7 This Agreement shall be governed by and construed in accordance 
with the laws of the State of California without regard to its choice of laws 
principles.  This Agreement shall be construed and interpreted without 
application of any principle or rule to the effect that ambiguities are to be 
construed against the party responsible for drafting the agreement. The 
headings contained herein are for reference purposes only and shall not in 
any way affect the meaning of this Agreement.

     14.8 This Agreement may be executed in any number of counterparts, each 
of which shall be deemed an original, but all of which together shall 
constitute one instrument.

     IN WITNESS WHEREOF, the parties have executed this Agreement through 
duly authorized representatives as of the Effective Date.

NANOGEN, INC.                              HOECHST RESEARCH & TECHNOLOGY
                                           DEUTSCHLAND GMBH & CO KG




By  /s/ Howard C. Birndorf                 By   /s/ Dr. Reiner Henning
   ------------------------------------      ---------------------------------
           Howard C. Birndorf                            President
  Chairman and Chief Executive Officer
                                           By   /s/ Dr. Hans-Ullrich Hoppe
                                             ---------------------------------
                                                Research Operations Director


                                     -17-
<PAGE>

                            EXHIBIT A

         NANOGEN'S "APEX" PATENTS AND PATENT APPLICATIONS

<TABLE>
<CAPTION>

            TITLE                          APPLICATION NO.                           DATE
            -----                          ---------------                           ----
<S>                                     <C>                                <C>
Active Programmable Electronic
Devices for Molecular Biological
Analysis and Diagnostics (203/218)         USP 5,605,662                      Issued:  02/25/97

             ***                                 ***                                  ***

Molecular Biological Diagnostic
Systems Including Electrodes (209/062)     USP 5,632,957                      Issued:  05/27/97

Apparatus and Methods for Active
Programmable Matrix Devices (216/054)      USP 5,849,486                      Issued:  12/15/98

             ***                                 ***                                  ***

</TABLE>

----------------------------------------
***    Confidential material redacted and separately filed with the Commission.



                                     -18-
<PAGE>

                            EXHIBIT B

        C.R. & T'S "ELIAS" AND "PRNA" PATENT APPLICATIONS

<TABLE>
<CAPTION>

     TITLE     APPLICATION NO.          DATE
     -----     ---------------          ----
<S>            <C>                  <C>
      ***           ***                 ***

</TABLE>





----------------------------------------
***    Confidential material redacted and separately filed with the Commission.

                                     -19-
<PAGE>

                            EXHIBIT C

                      TOTAL PROGRAM (YEAR 1)

     Personnel of Hoechst   ***   Nanogen     ***
     Materials of Hoechst         ***   Nanogen     ***



----------------------------------------
***    Confidential material redacted and separately filed with the Commission.


                                     -20-
<PAGE>

                          MATERIAL COSTS

<TABLE>

<S>                             <C>                  <C>
TDM/PROJECT YEAR:

SYNTHESIS

Equipment (Synthesizer. . .)       ***                  (Depreciation over *** Years)
Analytics                          ***
Chemicals                          ***
                                   ---
Total                              ***

PERMEATION LAYER

Equipment (Spin Coater. . .)       ***                  (Depreciation over *** Years)
Materials (Chemicals)              ***
                                   ---
Total                              ***

DIRECT READ-OUT

Equipment                          ***
                                   ---

TOTAL            ***  (*** TUS$)

</TABLE>

----------------------------------------
***    Confidential material redacted and separately filed with the Commission.


                                     -21-
<PAGE>

                         EXHIBIT C (CR&T)

                            PERSONNEL

<TABLE>
<CAPTION>


TASK                                                    HEADCOUNT
----                                                    ---------
<S>                                                  <C>
SYNTHESIS

      PhD, Organic Chemists                               ***
      Postdocs, Lab Technicians                           ***

PERMEATION LAYER

      PhD's Organic Chemist,
      Physicist                                           ***
      PhD (Japan)                                         ***
      Postdocs, Lab Technicians                           ***

DIRECT ELECTRONIC READ-OUT

      PhD's (Japan)                                       ***
      Lab Technicians                                     ***
      PhD Biophysical-Chemist                             ***

PROGRAM MANAGEMENT                                        ***

Total Headcount                                           ***

</TABLE>

-------------------------------------
***    Confidential material redacted and separately filed with the Commission.


                                     -22-
<PAGE>

                             SHEET 1

                       EXHIBIT C (NANOGEN)

                        PERSONNEL/NANOGEN

<TABLE>
<CAPTION>

      TASK                                YEAR 1             YEAR 2
      ----                               --------           --------
<S>                                    <C>                <C>
CHIP
    Process engineer                       ***               ***
    Software engineer                      ***               ***
    Test engineer                          ***               ***
    Test Tech                              ***               ***
    Packaging Engineer                     ***               ***
    Packaging Tech                         ***               ***

INSTRUMENT
    Electrical engineer                    ***               ***
    Software engineer                      ***               ***
    Mechanical engineer                    ***               ***

PERMEATION LAYER
    Chemical engineer                      ***               ***

ASSAY DEVELOPMENT
    Physical chemist                       ***               ***
    Biochemist                             ***               ***

PROGRAM MANAGEMENT
    Program Manager                        ***               ***

TOTAL HEADCOUNT                            ***               ***

</TABLE>

------------------------------------
***    Confidential material redacted and separately filed with the Commission.



                                     -23-
<PAGE>

                             SHEET 1

                     MATERIALS COSTS/NANOGEN

<TABLE>
<CAPTION>

        TASK                     YEAR 1      YEAR 2
        ----                     ------      ------
<S>                            <C>         <C>
CHIP
       Design                     $***        $***
       Masks                      $***        $***
       Wafer fab                  $***        $***
       Test                       $***        $***
       Packaging                  $***        $***
         TOTAL                    $***        $***

INSTRUMENTS
       Read-out                   $***
       Probe placement                        $***
         TOTAL                    $***        $***

PERMEATION LAYER/CHEMISTRY
       Perm Layer                 $***
       Attachment Chem.                       $***
         TOTAL                    $***        $***

ASSAY
       Reagents                   $***        $***

          TOTAL PROGRAM           $***        $***
</TABLE>



-----------------------------------
***    Confidential material redacted and separately filed with the Commission.




                                     -24-