Exhibit 10.4

FIRST AMENDED AND RESTATED SECURITY AGREEMENT

This First Amended and Restated Security Agreement (the “Agreement”) is made as
of October 17, 2007 by BioTime, Inc., as the “Debtor,” in favor and for the
benefit of Alfred D. Kingsley, George Karfunkel, Richard Lowish, Broadwood
Partners, L.P., individually and collectively, as the “Secured Party,” and
amends and restates that certain Security Agreement dated April 12, 2006.

PREMISES

A. Debtor and Secured Party have entered into that certain First Amended and
Restated Revolving Line of Credit Agreement of even date (the “Credit
Agreement”), pursuant to which Debtor may borrow funds from Secured Party;

B. Debtor has delivered to certain Secured Parties Amended and Restated
Revolving Credit Notes, dated April 12, 2006, in the aggregate principal amount
of $200,000, and has delivered to certain Secured Parties Revolving Credit
Notes, dated October __, 2007, in the aggregate principal amount of $800,000
(collectively, the “Notes” and each a “Note”) evidencing Debtor’s obligation to
pay funds advanced by Secured Party under the Credit Agreement;

C. Debtor is entering into this Agreement to secure its obligations under the
Credit Agreement.

AGREEMENT

NOW, THEREFORE, in consideration of the premises and for other good and valuable
consideration, the receipt and adequacy of which is hereby acknowledged, Debtor
hereby agrees as follows:

1.    Creation of Security Interest. Debtor hereby conveys, assigns, transfers,
and grants to Secured Party a first priority perfected security interest in all
of Debtor’s present and hereafter acquired right, title, and interest in and to
the Collateral (as defined in Section 3 below). Secured Party may record a UCC-1
Financing Statement concerning the Collateral.

2.    Secured Obligations. This Agreement and the security interests granted and
created under this Agreement secure the prompt payment in full in cash and the
full performance of each and all of the following obligations (collectively, the
“Secured Obligations”):
 
                2.1   each and every obligation, covenant, and agreement of
Debtor contained in, arising under, in connection with, or evidenced by each of
the Notes;
 
                               2.2   the obligations, covenants and agreements
of Debtor under the Credit Agreement; and

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                               2.3   each and every obligation, covenant, and
agreement of Debtor contained in, arising under, or in connection with, or
evidenced by this Agreement.
 
    3.                Collateral.  As used in this Agreement, the term
Collateral means (a) of Debtor’s right, title, and interest in and to all
royalties, license fees, and other amounts payable by Hospira, Inc. or any
successor under that certain Exclusive License Agreement, dated April 23, 1997,
between Debtor and Abbott Laboratories, Inc. (as the predecessor in interest to
Hospira, Inc.), as modified by a letter agreement and as amended by that certain
Amendment to BioTime License Agreement, dated January 9, 2006 (the “Hospira
License”), and (b) all accounts, accounts receivable, notes, and instruments
evidencing any obligation of payment by Hospira, Inc. under the Hospira License
; and (c) all proceeds of the Collateral described in clauses (a) and (b) of
this Section 3, including but not limited to, money, accounts, general
intangibles, securities, deposit accounts, investment property, documents,
chattel paper, instruments, and insurance proceeds and interests therein. Debtor
represents and warrants to and for the benefit of Secured Party that Debtor’s
title to the Collateral described in clause (a) of the preceding sentence is
free and clear of all liens, pledges, encumbrances, equities, and claims of any
kind whatsoever except for the security interest created by this Agreement.
 
    4.                Further Assurances.  Debtor hereby further agrees to
procure, execute, and deliver on demand and Debtor hereby irrevocably appoints
Secured Party as Debtor’s attorney in fact to execute, acknowledge, deliver,
and, if appropriate, file and record such endorsements, assignments, consents,
security agreements, financing statements, control agreements, or other
instruments, documents, or writings as Secured Party may request or require in
order to perfect or continue the perfection and the priority of the security
interests created or agreed to be created by this Agreement.
 
    5.                Transfers and Other Liens.  Without the prior written
consent of Secured Party, Debtor shall not (a) sell, contract to sell, pledge,
encumber, assign, hypothecate, alienate, convey, dispose, or otherwise transfer
the Collateral, or any interest therein, whether voluntarily, involuntarily, or
by operation of law, except for sales of inventory in the ordinary course of
business, (b) consent or agree to any alteration, modification, or amendment to
the Hospira License that would reduce the royalties payable by Hospira , (c)
waive any right of payment, or grant any grace period or extension of time for
the payment, of any royalties by Hospira under the Hospira License, (d) create
or permit to exist any lien, encumbrance, mortgage, pledge, security interest or
charge of any kind upon or concerning any of the Collateral, except for the
security interest created by this Agreement, or (e) take any action concerning
the Collateral that is inconsistent with the provisions and purposes of this
Agreement. Any sale, contract to sell, pledge, conveyance, hypothecation,
alienation, encumbrance, disposition, assignment, or other transfer of any of
the Collateral or any alteration, modification, or amendment of any of the
Collateral in a manner that would delay or reduce royalty payments, or the grant
of any grace period or extension of time for the performance of any obligation
due for the benefit of Debtor or Secured Party under or concerning any of the
Collateral made, permitted, or suffered without Secured Party’s prior written
consent shall constitute an Event of Default under this Agreement.
 
 
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    6.                Additional Covenants of Debtor.  In addition to all other
covenants and agreements of Debtor set forth in this Agreement, Debtor agrees to
(a) give Secured Party thirty (30) days prior written notice of any change in
Debtor’s name, state of incorporation or organization, or place of business, or,
if Debtor has more than one place of business, its head office or office in
which Debtor’s records relating to the Collateral are kept; (b) to appear in and
defend any action or proceeding which may affect Debtor’s title to or Secured
Party’s interest in any Collateral; and (c) to keep separate, accurate, and
complete records of the Collateral, and to provide Secured Party with such
records and such other reports and information relating to Collateral as Secured
Party may request from time to time.
 
    7.                Certain Notifications and Distributions With Respect To
Collateral. Upon the occurrence and continuance of an Event of Default, Secured
Party shall have the rights set forth in this Section. Secured Party may at any
time, and from time to time, notify Hospira or any successor account debtor that
(a) an account or instrument constituting Collateral has been assigned to
Secured Party, and (b) all distributions and payments and the performance of all
obligations in any way related to the Collateral are to be made directly to
Secured Party. If Debtor receives any payments of money, securities, or any
tangible or intangible property on account of or with respect to any of the
Collateral at any time during which an Event of Default shall have occurred and
be continuing, such payments will be received by Debtor in trust for, and
immediately paid over to Secured Party. Any collections received by Secured
Party or received by Debtor and delivered to Secured Party shall be applied to
the Secured Obligations, first to the expenses of collection, second to the
payment of accrued interest, and third to the payment of principal; provided,
that any amounts remaining after payment in full of all expenses, interest, and
principal shall be returned to Debtor. Secured Party shall have the right to
receive, receipt for, endorse, assign, deposit, and deliver, in Secured Party’s
name or in the name of Debtor, any and all checks, notes, drafts, and other
instruments for the payment of money constituting proceeds of or otherwise
relating to the Collateral. Debtor hereby authorizes Secured Party to affix, by
facsimile signature or otherwise, the general or special endorsement of Debtor,
in such manner as Secured Party shall deem advisable, to any such instrument in
the event the same has been delivered to Secured Party without appropriate
endorsement, and Secured Party and any collecting bank are hereby authorized to
consider such an endorsement as being by Debtor to the same extent as though it
were manually executed by Debtor, regardless of by whom or under what
circumstances or by what authority such facsimile signature or other endorsement
is actually affixed, without duty of inquiry or responsibility as to such
matters, and Debtor hereby waives demand, presentment, protest, and notice of
protest or dishonor and all other notices of every kind and nature with respect
to any such instrument.

8.            Rights Upon Event of Default.
 
                               8.1          Upon the occurrence of an Event of
Default under this Agreement, Secured Party shall have, in addition to all other
rights and remedies that Secured Party may have at law or in equity, under
Section 7 of this Agreement, or under any other agreement executed by Debtor in
favor of Secured Party, all rights and remedies of a secured party under the
California Commercial Code, which rights and remedies of Secured Party shall be
cumulative and non-exclusive. In addition, upon the occurrence of an Event of
Default, Secured Party shall have the following rights and remedies, all of
which may be exercised with or without further notice to Debtor: (i) to directly
receive any and all payments and distributions of money, securities or any
tangible or intangible property on or in any way related to the Collateral; (ii)
to
 
 
 
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settle, compromise, or release, on terms acceptable to Secured Party, in whole
or in part, any amounts owing on the Collateral; (iii) to enforce payment and to
prosecute any action or proceeding with respect to any and all of the
Collateral; (iv) to foreclose the liens and security interests created under
this Agreement or under any other agreement relating to the Collateral by any
available procedure, with or without judicial process; (v) to sell, assign, or
otherwise dispose of the Collateral or any part thereof, either at public or
private sale for cash, on credit, or otherwise, with or without representations
or warranties, and upon such terms as shall be acceptable to Secured Party; all
at Secured Party’s sole option and as Secured Party in their sole discretion may
deem advisable.
 
          8.2          Debtor shall be given reasonable notice of the time and
place of any public sale of the Collateral, or of the time on or after which any
private sale or other intended disposition is to be made. If required under
applicable law, Secured Party may be the purchaser at any public sale. Ten days
notice of any public or private sale or other disposition shall be considered to
be reasonable notice.

9.   Disposition of Proceeds.  After satisfaction in full of the Secured
Obligations, the balance of the proceeds of sale then remaining shall be paid
first to satisfy obligations secured by any other subordinate security interests
or subordinate liens (including but not limited to attachment liens and
execution liens) in the Collateral as provided in the California Commercial
Code, and then any remaining balance of the proceeds shall be paid to the
Debtor.

10.        Events of Default. The occurrence of any of the following shall
constitute an Event of Default under this Agreement:
 
          10.1   Secured Party shall fail or cease to have a first priority
perfected security interest in the Collateral or any part of the Collateral
unless caused by any action taken by Secured Party;
 
          10.2   Debtor defaults in the performance of any covenant or agreement
contained in this Agreement;
 
          10.3   Debtor defaults in the payment or performance of any Secured
Obligation;
 
          10.4   An Event of Default as defined in the Notes has occurred with
respect to any of the Notes; and
 
          10.5   The occurrence of any other event under this Agreement that is
specifically described elsewhere within this Agreement as an Event of Default.

11.   Amendments. This Agreement may not be altered or amended except with the
written consent of Debtor and the Secured Party.

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       12.   Binding on Successors and Assigns.  This Agreement shall be binding
upon and inure to the benefit of Debtor and Secured Party and their respective
heirs, executors, personal representatives, successors and assigns.
 
              13.   Notices.  All notices and other communications required or
permitted to be given pursuant to this Agreement shall be in writing and shall
be deemed given four (4) days after being deposited in the United States mail,
certified postage prepaid, return receipt requested, or when delivered by hand,
by messenger or express air freight service to the address for notice shown in
the Credit Agreement. Any party may change its address for notice by giving
notice to the other party in the same manner as provided in this section.

14.   Governing Law.  This Agreement shall be governed by and construed under
the laws of the State of California without regard to conflicts of law. Where
applicable and except as otherwise defined in this Agreement, the terms used in
this Agreement shall have the meanings given them in the California Commercial
Code.

15.   Attorneys Fees and Costs of Enforcement.  Debtor agrees to pay
all reasonable attorneys’ fees incurred by Secured Party in connection with
enforcement of any of Secured Party’s rights and remedies under this Agreement,
whether or not any proceeding is commenced to enforce or protect such rights and
remedies. All advances, charges, costs, and expenses, including without
limitation, reasonable attorneys’ fees, incurred or paid by Secured Party in
exercising any right, power, or remedy conferred by this Agreement, or in the
enforcement thereof, shall be added to and shall become a part of the Secured
Obligations, payable by Debtor on demand with interest thereon at a rate of
interest equal to the lesser of: (i) the rate provided in the Note for interest
payable after an Event of Default, or (ii) the maximum rate of interest
permitted by law.

16.   Waivers by Debtor.  Debtor expressly waives any right to require Secured
Party to (a) proceed against any person, (b) marshal assets or proceed against
or exhaust Collateral or any part thereof, or (c) pursue any other remedy in
Secured Party’s power; and Debtor waives any defense arising by reason of any
disability or other defense of any other person or entity, or by reason of the
cessation from any cause whatsoever of the liability of Debtor or any other
person or entity. Debtor consents and agrees that Secured Party may, at any time
and from time to time, without notice or demand, and without affecting the
enforceability or continuing effectiveness of this Agreement: (i) accept new or
additional instruments, documents, or agreements in exchange for or relative to
any or all of the Secured Obligations; (ii) accept partial payments on or
partial performance of any or all of the Secured Obligations; (iii) receive and
hold additional security or guaranties for any or all of the Secured Obligations
or any part thereof; (iv) release, reconvey, terminate, waive, abandon, fail to
perfect, subordinate, exchange, substitute, transfer, and enforce any security
or guaranties; (v) apply any Collateral or other security and direct the order
or manner of sale thereof as Secured Party may determine;(vi) consent to the
transfer of any Collateral or other security for any or all of the Secured
Obligations; and (vii) bid and purchase at any sale of Collateral.
 
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              17.         Cumulative Rights of Secured Party.  The rights,
powers, and remedies given to Secured Party by this Agreement shall be in
addition to all rights, powers, and remedies given to Secured Party by virtue of
any statute, rule of law, or any other agreement between Debtor and Secured
Party. Any forbearance or failure or delay by Secured Party in exercising any
right, power, or remedy under this Agreement shall not preclude the further
exercise thereof; and every right, power, and remedy of Secured Party shall
continue in full force and effect until such right, power, or remedy is
specifically waived by an instrument in writing signed by Secured Party.

18.        Termination.  Secured Party’s security interest in the Collateral
shall terminate upon the satisfaction in full of all Secured Obligations, and at
that time Secured Party shall return to Debtor all Collateral then in Secured
Party’s possession.
 
              19.         Power of Attorney.  Debtor hereby irrevocably appoints
Secured Party as attorney-in-fact of Debtor, with full power of substitution, to
sign any document necessary to transfer title to any of the Collateral and to do
all acts necessary or incident to the powers granted under this Agreement to
Secured Party, as fully as Debtor might, including without limitation, the
execution and recordation of any claim of lien on behalf of and in the name of
Debtor.

DEBTOR

BIOTIME, INC.

By:       /s/ Michael D. West                                         
Chief Executive Officer

By:      /s/ Judith Segall                                                 
Secretary
 
 
                                                                                                        
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