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                                                                  EXHIBIT 10.8.1

                        AMENDMENT A TO LICENSE AGREEMENT

This amendment agreement (the "Amendment A") is entered into by the parties to
the existing license agreement effective November 9, 2002 (the "Prior
Agreement") between The Regents of the University of California, Department of
Energy contract-operators of the Ernest Orlando Lawrence Berkeley National
Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, ("Berkeley Lab"), and Nanosys,
Inc., a Delaware corporation ("Licensee") having its principal place of business
at 2625 Hanover St., Palo Alto, CA 94304.

For good and valuable consideration, receipt and sufficiency of which is hereby
acknowledged, the Berkeley Lab and Licensee agree as follows:

I.       BACKGROUND

The Berkeley Lab and Licensee are parties to the Prior Agreement (Berkeley Lab
reference L-03-1364) relating generally to certain inventions characterized as
nanocrystals and related technology.

The Berkeley Lab and Licensee would like to amend the Prior Agreement by way of
this Amendment A to include license rights to certain new inventions made in the
course of research at Berkeley Lab by Dr. Paul Alivasatos and colleagues under
Berkeley Lab's contract with the United States Department of Energy ("DOE"),
relating generally to [*** Redacted] applications of [*** Redacted] and related
technology.

II.      AMENDMENT FEE

Licensee shall pay to the Berkeley Lab an Amendment Fee in the amount of [***
Redacted], which accrues upon execution of this Amendment, with [*** Redacted]
being payable within 30 days of the execution of this Amendment, and the
remaining [*** Redacted] being payable within 12 months of the execution
date of this Amendment.

III.     AMENDMENTS TO THE PRIOR AGREEMENT

A.       Paragraph 5.1 of the Prior Agreement is hereby deleted in its entirety
         and replaced with the following amended paragraph 5.1:

         5.1      Following an initial public offering or series of public
                  offerings of Licensee securities which raises in the aggregate
                  at least $5 million or sale of all or substantially all of the
                  assets or equity of Licensee in a


*** Confidential treatment requested pursuant to a request for confidential
treatment filed with the Securities and Exchange Commission. Omitted portions
have been filed separately with the Commission.
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                  transaction(s) worth at least $5 million ("Offering"),
                  Licensee shall pay to Berkeley Lab the equivalent of the price
                  at the Offering of 70,000 shares of Licensee's common stock.
                  Such payments shall be made in installments with one-third
                  payable 9 months from the Offering, one-third payable 18
                  months from the Offering and one-third payable 26 months from
                  the Offering. Such payments shall include interest from the
                  date of the Offering to the date such payment is made.
                  Interest shall be compounded on the date such payment is made,
                  and shall be charged at the prime lending rate as published in
                  the Wall Street Journal on the date such payment is made.
                  Licensee shall adjust the 70,000 shares to take into account
                  any stock splits or reverse stock splits since the Effective
                  Date.

B.       Paragraph 7.4 of the Prior Agreement is hereby amended to insert after
paragraph 7.4.l0. the following additional paragraphs:

         7.4.11   by 24 months from the Effective Date, have expended at
                  least [*** Redacted] in the aggregate for direct costs in
                  research and development for technology directly related to
                  [*** Redacted] applications that use Licensed Patents;

         7.4.12   by 24 months from the Effective Date, provide Berkeley Lab
                  with a commercialization plan for [*** Redacted] devices based
                  upon the Licensed Patents;

         7.4.13   by 48 months from the Effective Date, produce in Licensee's
                  facility, a working prototype [*** Redacted] device with at
                  least [*** Redacted];

         7.4.14   by 60 months from the Effective Date, make commercial sales of
                  Licensed Products that are [*** Redacted] devices

C.       Paragraph 9.1 of the Prior Agreement is hereby deleted in its entirety
         and replaced with the following amended paragraph 9.1:

         9.1      Licensee shall keep books and records accurately showing all
                  work performed in satisfaction of Article 7 and all Licensed
                  Products manufactured, used, sold or imported under the terms
                  of this Agreement, including without limitation books and
                  records related to licenses for Third Party Patents under
                  paragraph 6.4. Licensee shall preserve those

*** Confidential treatment requested pursuant to a request for confidential
treatment filed with the Securities and Exchange Commission. Omitted portions
have been filed separately with the Commission.

                                       2

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                  books and records for at least [*** Redacted] years from the
                  date of the work performed or the royalty payment to which
                  they pertain and shall open them to inspection by
                  representatives or agents of Berkeley Lab at reasonable times.
                  Licensee shall render all assistance reasonably requested by
                  Berkeley Lab for the purposes of carrying out such inspections
                  and examination of Licensee's royalty payments and performance
                  under Article 7.

D.       Exhibit 1 and Exhibit 2 of the Prior Agreement are hereby deleted in
         their entirety and replaced with the attached amended Exhibit 1 and
         Exhibit 2.

IV.      NO OTHER AMENDMENTS

Unless expressly amended herein or by subsequent amendments agreed to by the
parties in a signed written amendment, all other terms of the Prior Agreement,
including but not limited to terms related to interpretation and enforcement of
the Prior Agreement, shall remain in full force and effect as originally agreed
to in the Prior Agreement, and shall apply equally to the terms of this
Amendment A.

Berkeley Lab and Licensee execute this Agreement in duplicate originals through
their duly authorized respective officers in one or more counterparts, that
taken together, are but one instrument.

THE RECENTS OF THE UNIVERSITY            NANOSYS, INC.
OF CALIFORNIA, THROUGH THE
ERNEST ORLANDO LAWRENCE
BERKELEY NATIONAL LABORATORY

By /s/ Piermaria Oddone                  By  /s/ Lawrence Bock
   -------------------------------           --------------------------
        (Signature)                                (Signature)

By   Piermaria Oddone                    By      Lawrence Bock

Title  Deputy Laboratory Director        Title    President

Date  3/18/03                            Date    3/20/03

      Approved as to form
      /s/ Glenn R. Woods
      ---------------------
      GLENN R. WOODS
      LAWRENCE BERKELEY NATIONAL LABORATORY

*** Confidential treatment requested pursuant to a request for confidential
treatment filed with the Securities and Exchange Commission. Omitted portions
have been filed separately with the Commission.

                                        3
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                                    EXHIBIT 1

                          LICENSED (EXCLUSIVE) PATENTS

BERKELEY LAB
CASE NUMBER                      PATENT APPLICATION/PATENT

IB-1810           The following Provisional U.S. Patent Applications by A. Paul
                  Alivisatos, Wendy U. Huynh, and Janke J. Dittmer:

                  (1) 60/365,401, filed March 18, 2002, entitled Solar Cells,
                  Photovoltaic Devices and Photodectectors Based on Inorganic
                  Nanorods and Other 3D Objects Based on Nanorods;

                  (2) 60/381,660, filed May 17, 2002, entitled, Hybrid
                  Nanorod-Polymer Solar Cells;

                  (3) 60/381,667, filed May 17, 2002, entitled, Hybrid
                  Nanorod-Polymer Solar Cells

IB-1783           US Patent Application Serial Number 10/280,135, filed
                  10/23/02, entitled, Semiconductor Liquid Crystal Composition
                  and Methods for Making Same, by A. Paul Alivisatos and
                  Liang-shi Li

IB-1783PCT        Patent Application filed under Chapter I of the Patent
                  Cooperation Treaty, Serial Number PCT/US02/33970, filed
                  10/23/02, entitled, Quantum Rod Liquid Crystals, by A. Paul
                  Alivisatos and Liang-shi Li

IB-1576           US Patent Application Serial Number 09/702,219, filed
                  10/30/00, entitled, Process for Making Surfactant-capped
                  Nanocrystals, by A. Paul Alivisatos and Joerg Rockenberger

IB-1576A          US Patent Application Serial Number 09/721,126, filed
                  11/22/00, entitled, A Process for Making Surfactant Capped
                  Nanocrystals and Products Produced by the Process, by A. Paul
                  Alivisatos and Joerg Rockenberger

IB-1402           [*** Redacted]

*** Confidential treatment requested pursuant to a request for confidential
treatment filed with the Securities and Exchange Commission. Omitted portions
have been filed separately with the Commission.

<PAGE>

                                    EXHIBIT 2

                        LICENSED (FOU EXCLUSIVE) PATENTS

BERKELEY LAB                         PATENT APPLICATION/PATENT
CASE NUMBER

IB-1773           U.S. patent application, Serial Number 10/301,510, filed
                  11/22/02, entitled Shaped Nanocrystal Particles and Methods
                  for Making the Same, by A. Paul Alivisatos, Erik Scher, and
                  Liberato Manna

IB-1773PCT        Patent Application filed under Chapter I of the Patent
                  Cooperation Treaty, Serial Number pending, filed 11/22/02,
                  entitled, Shaped Nanocrystal Particles and Methods for Making
                  the Same, by A. Paul Alivisatos, Erik Scher, and Liberato
                  Manna

IB-1527A          US Patent Number 6,225,198, issued May 1, 2001, entitled
                  Process for Forming Shaped Group II-VI Semiconductor
                  Nanocrystals, and Product Formed Using Process, by A. Paul
                  Alivisatos, Xiaogang Peng, and Liberato Manna

IB-1527B          US Patent Number 6,306,736, issued October 23, 2001, entitled
                  Process for Forming Shaped Group III-V Semiconductor
                  Nanocrystals, and Product Formed Using Process, by A. Paul
                  Alivisatos, Xiaogang Peng, and Liberato Manna

IB-1330           US Patent Number 5,990,479, issued November 23, 1999, entitled
                  Organoluminescent Semiconductor Nanocrystal Probes for
                  Biological Applications and Process for Making and Using Such
                  Probes, by Shimon Weiss, Marcel Bruchez, Jr., and A. Paul
                  Alivisatos

IB-1330JP         Japanese Patent Application Number 11-80598, filed 3/24/99,
                  entitled, Semiconductor Nanocrystal Probes for Biological
                  Applications and Process for Making and Using Such Probes, by
                  Shimon Weiss, Marcel Bruchez, Jr., and A. Paul Alivisatos

IB-1330A          US Patent Number 6,207,392, issued March 27, 2001, entitled
                  Semiconductor Nanocrystal Probes for Biological Applications
                  and Process for Making and Using Such Probes, by Shimon Weiss,
                  Marcel Bruchez, Jr., and A. Paul Alivisatos

IB-1330A-EPO      European Patent Organization Application number 00915944.3,
                  filed 2/28/00, entitled Semiconductor Nanocrystal Probes for
                  Biological Applications and Process for Making and Using Such
                  Probes, by Shimon Weiss, Marcel Bruchez, Jr., and A. Paul
                  Alivisatos

IB-1330A-CA       Canadian Patent Application Number 2366303, filed 8/10/01,
                  entitled Semiconductor Nanocrystal Probes for Biological
                  Applications and Process for Making and Using Such Probes, by
                  Shimon Weiss, Marcel Bruchez, Jr., and A. Paul Alivisatos

IB-1330A-JP       Japanese Patent Application Number 2000-605212, entitled
                  Semiconductor Nanocrystal Probes for Biological Applications
                  and Process for Making and Using Such Probes, by Shimon Weiss,
                  Marcel Bruchez, Jr., and A. Paul Alivisatos

IB-1330B          US Patent Number 6,423,551 issued July 23, 2002, entitled
                  Organo luminescent Semiconductor Nanocrystal Probes for
                  Biological Applications and Process for Making and Using Such
                  Probes, by Shimon Weiss, Marcel Bruchez, Jr., and A. Paul
                  Alivisatos

IB-1330C          US Patent Application Serial Number 09/781,621, filed
                  2/12/2001, entitled Semiconductor Nanocrystal Probes for
                  Biological Applications and Process for Making and Using Such
                  Probes, by Shimon Weiss, Marcel Bruchez, Jr., and A. Paul
                  Alivisatos

B-1330D           US Patent Application Serial Number 09/865,130, filed
                  5/24/2001, entitled Organo luminescent Semiconductor
                  Nanocrystal Probes for Biological Applications and Process for
                  Making and Using Such Probes, by Shimon Weiss, Marcel Bruchez,
                  Jr., and A. Paul Alivisatos

IB-1330E          US Patent Application Serial Number 10/155,918, filed
                  5/24/2002, entitled Organo luminescent Semiconductor
                  Nanocrystal Probes for Biological Applications and Process for
                  Making and Using Such Probes, by Shimon Weiss, Marcel Bruchez,
                  Jr., and A. Paul Alivisatos

IB-I330F          US Patent Application Seri al Number 10/155,759, filed
                  5/24/2002, entitled Semiconductor Nanocrystal Probes for
                  Biological Applications and Process for Making and Using Such
                  Probes, by Shimon Weiss, Marcel Bruchez, Jr., and A. Paul
                  Alivisatos

CIB-1030          US Patent Number 5,537,000, issued July 16, 1996, entitled
                  Electroluminescent Devices Formed Using Semiconductor
                  Nanocrystals as an Electron Transport Media and Method of
                  Making Such Electroluminescent Devices, by A. Paul Alivisatos
                  and Vicki L. Colvin

IB-866A           US Patent Number 5,751,018, issued May 12, 1998, entitled
                  Semiconductor Nanocrystals Covalently Bound to Solid Inorganic
                  Surfaces Using Self-Assembled Monolayers, by A. Paul
                  Alivisatos and Vicki L. Colvin

IB-865            US Patent Number 5,262,357, issued November 16, 1993, entitled
                  Low Temperature Thin Films Formed Via Nanocrystal Precursors,
                  by A. Paul Alivisatos and Avery N. Goldstein

IB-864A           US Patent Number 5,505,928, issued April 9, 1996, entitled
                  Preparation Of III-V Semiconductor Nanocrystals, by A. Paul
                  Alivisatos and Michael A. Olshavsky