<PAGE>   1
EXHIBIT *(10.27)

                          TRADEMARK SECURITY AGREEMENT

      This Trademark Security Agreement ("Agreement") is made as of the 29th day
of October, 1999 by IGEN, INC. ("Grantor"), a Delaware corporation, and
successor by merger to Medatz, Inc., which was successor by purchase to certain
trademarks originally owned by Vineland Laboratories, Inc having a mailing
address at Wheat Road and Lincoln Avenue, Buena, NJ 08310, and delivered to
FLEET CAPITAL CORPORATION, a Rhode Island corporation having a mailing address
at 200 Glastonbury Blvd., Glastonbury, CT 06033 ("Lender").


                                   BACKGROUND

      A. This Agreement is being executed contemporaneously with that certain
Loan and Security Agreement of even date herewith among Grantor, IGI, Inc.,
ImmunoGenetics, Inc., and Blood Cells, Inc. (collectively, "Borrowers") and
Lender (as it may hereafter be supplemented, restated, amended, superseded or
replaced from time to time, the "Loan Agreement"), under which, inter alia,
Borrower is granting Lender a lien on and security interest in certain assets of
Borrower associated with or relating to products leased or sold or services
provided under Borrower's trademarks and the goodwill associated therewith as
security for the payment and performance of all the Obligations (as defined in
the Loan Agreement) of all the Borrowers under the Loan Agreement, and under
which Lender is entitled to foreclose or otherwise deal with such assets,
trademarks, service marks and tradenames under the terms and conditions set
forth therein. Capitalized terms not defined herein shall have the meanings
given to such terms in the Loan Agreement.

      B. Grantor owns, has adopted, used and is using (or has filed applications
for the registration of) the trademarks, servicemarks and tradenames listed on
SCHEDULE "A" attached hereto and made part hereof (all such marks or names
hereinafter referred to as the "Schedule A Trademarks"). In addition, Grantor
has the right under a certain license agreement dated December 13, 1995 between
Grantor and Micro-Pak, Inc. ("License Agreement") to use certain trademarks,
servicesmarks and tradenames owned by Micro-Pak, Inc. listed on SCHEDULE "B"
attached hereto and made part hereof (all such marks and names hereinafter
referred to as the "Schedule B Trademarks.") Collectively, the Schedule A
Trademarks and the Schedule B Trademarks shall be referred to as the
"Trademarks."

      C. Pursuant to the Loan Agreement, Lender is acquiring a lien on, security
interest in, and license to use (which license is conditioned upon the
occurrence and continuance of an Event of Default) the Schedule A Trademarks and
the Grantor's rights under the License Agreement, together with all the goodwill
of Grantor associated therewith and represented thereby, as security for all of
the Obligations, and desires to have its security interest in such Schedule A
Trademarks and the Grantor's right to use the Schedule B Trademarks and other
rights under the License Agreement confirmed by a document identifying same and
in such form that it may be recorded in the United States Patent and Trademark
Office.

      NOW THEREFORE, with the foregoing Background hereinafter deemed
incorporated by reference and made a part hereof, and in consideration of the
premises and mutual promises herein contained, the parties hereto, intending to
be legally bound hereby, covenant and agree as follows:


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      1. In consideration of and pursuant to the terms of the Loan Documents,
and for other good, valuable and sufficient consideration, the receipt of which
is hereby acknowledged, and to secure the payment and performance of all the
Obligations of all Borrowers under the Loan Agreement, Grantor grants a lien and
security interest to Lender in all of its present and future right, title and
interest in and to the Schedule A Trademarks and the Grantor's right to use the
Schedule B Trademarks and other rights under the License Agreement, together
with all the goodwill of Grantor associated with and represented by the
Trademark Collateral, and the registration thereof and the right (but not the
obligation) to sue for past, present and future infringements, and the proceeds
thereof, including, without limitation, license royalties and proceeds of
infringement suits, (collectively the "Collateral").

      2. Grantor hereby covenants and agrees to maintain the Trademarks in full
force and effect and otherwise perform all of its obligations and undertakings
under this Agreement until all of the Obligations are indefeasibly paid and
satisfied in full and the Loan Agreement has been terminated.

      3. Grantor represents, warrants and covenants that:

            (a)   The Trademarks are subsisting and have not been adjudged
invalid or unenforceable;

            (b) Each of the Trademarks is registered (or in the process of
application for registration), and, to the best of Grantor's knowledge, is valid
and enforceable;

            (c) Grantor is the sole and exclusive owner of the entire and
unencumbered right, title and interest in and to each of the Schedule A
Trademarks, and except for Liens permitted under Section 8.2.5 of the Loan
Agreement, each of the Schedule A Trademarks is free and clear of any liens,
claims, charges and encumbrances, including, without limitation, pledges,
assignments, options, and covenants by Grantor not to sue third persons;

            (d) Except for Liens permitted under Section 8.2.5 of the Loan
Agreement, the Grantor's rights under the License Agreement, including the right
to use the Schedule B Trademarks, are free and clear of any liens, claims,
charges and encumbrances, including, without limitation, pledges, assignments,
options, and covenants by Grantor not to sue third persons;

            (e) Grantor has the unqualified right, power and authority to enter
into this Agreement and perform its terms;

            (f) Grantor has complied with, and will continue for the duration of
this Agreement to comply with, the requirements set forth in 15 U.S.C.
Section 1051-1127 and any other applicable statutes, rules and regulations in
connection with its use of the Trademarks;

            (g) Grantor has used and will continue to use for the duration of
this Agreement consistent standards of quality in services or products leased or
sold under the Trademarks, and hereby grants to Lender and its employees and
agents the right (with no obligation of any kind upon Lender to do so) to visit
Grantor's affiliates, franchises or management locations and to inspect the use
of the Trademarks and quality control records relating thereto at reasonable
times during regular business hours to ensure Grantor's compliance with this
paragraph 3(f); and


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<PAGE>   3
            (h) Grantor has no notice of any suits or actions commenced or
threatened against it, or notice of claims asserted or threatened against it,
with reference to the Trademarks.

      4. Grantor further covenants that:

            (a) Until all of the Obligations have been indefeasibly paid and
satisfied in full and the Revolving Credit has been terminated, Grantor will not
enter into any agreement which is inconsistent with Grantor's obligations under
this Agreement or which restrict or impair Agent's right or priorities
hereunder.

            (b) If Grantor acquires rights of ownership to any new trademarks,
the provisions of this Agreement shall automatically apply thereto and such
trademarks shall be deemed part of the Schedule A Trademarks. Grantor shall give
Lender written notice promptly upon its first use thereof along with an amended
SCHEDULE "A". Furthermore, if Grantor acquires rights as a licensee to any new
trademarks, the provisions of this Agreement shall automatically apply thereto
and such trademarks shall be deemed part of the Schedule B Trademarks, and any
license agreement pursuant to which Grantor acquires such rights shall be deemed
to be included in the definition of "License Agreement." Grantor shall give
Lender written notice promptly upon its first use thereof along with an amended
SCHEDULE "B".

      5. So long as this Agreement is in effect and so long as Grantor has not
received notice from Lender that an Event of Default has occurred and is
continuing under the Loan Agreement and that Lender has elected to exercise its
rights hereunder, Grantor shall continue to have the right to use the Trademarks
and Lender shall have no right to use the Trademarks or issue any exclusive or
non-exclusive license with respect thereto, or assign, pledge or otherwise
transfer title in the Trademarks to anyone else.

      6. Grantor agrees not to sell, grant any option, assign or further
encumber its rights and interest in the Trademarks without prior written consent
of Lender or as may be expressly permitted under the Loan Agreement.
Notwithstanding the foregoing, and providing that no Default or Event of Default
has occurred and is outstanding, Grantor shall be entitled to license any
Trademarks in exchange for fair market consideration in the exercise of its
reasonable business judgment.


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<PAGE>   4
      7. Following the occurrence and during the continuance of an Event of
Default under the Loan Agreement, Lender, as the holder of a security interest
under the Uniform Commercial Code, as now or hereafter in effect in the State
whose law governs the interpretation of the Loan Agreement, may take such action
permitted under the Loan Documents, hereunder or under any law, in its exclusive
discretion, to foreclose upon or otherwise exercise its rights against the
Trademarks or the Grantor's rights under the License Agreement covered hereby.
For such purposes, Grantor authorizes and empowers Lender, its successors and
assigns, and any officer or agent of Lender as Lender may select, in its
exclusive discretion, as Grantor's true and lawful attorney-in-fact, with the
power to endorse Grantor's name on all applications, assignments, documents,
papers and instruments necessary for Lender to use the Trademarks or to grant or
issue any exclusive or non-exclusive license under the Trademarks to anyone
else, or necessary for Lender to assign, pledge, convey or otherwise transfer
title in or dispose of the Trademarks to anyone else including, without
limitation, the power to execute on Grantor's behalf a trademark assignment in
the form attached hereto as EXHIBIT I. Grantor hereby ratifies all that such
attorney shall lawfully do or cause to be done by virtue hereof and in
accordance with the terms hereof, except for the gross negligence or willful
misconduct of such attorney. This power of attorney shall be irrevocable for the
life of this Agreement, the Loan Documents, and until all the Obligations are
indefeasibly paid and satisfied in full and the Loan Agreement is terminated.

      8. This Agreement shall not be modified without the written consent of the
parties hereto.

      9. All rights and remedies herein granted to Lender shall be in addition
to any rights and remedies granted under the Loan Documents and shall be
cumulative. In the event of an inconsistency between this Agreement and the Loan
Agreement, the language of the Loan Agreement shall control.

      10. Upon full and unconditional satisfaction of all of the Obligations and
termination of the Revolving Credit, Lender shall execute and deliver to Grantor
all documents reasonably necessary to terminate Lender's security interest in
the Trademarks and the Grantor's rights under the License Agreement.

      11. Any and all reasonable fees, costs and expenses, of whatever kind or
nature, including the reasonable attorneys' fees and legal expenses incurred by
Lender in connection with the preparation and execution of this Agreement and
all other documents relating hereto, the filing or recording of any documents
(including all taxes in connection therewith) in public offices, the payment or
discharge of any taxes, reasonable counsel fees, maintenance fees, encumbrances
or costs otherwise incurred in protecting, maintaining, preserving the
Trademarks, or in defending or prosecuting any actions or proceedings arising
out of or related to the Trademarks, or defending, protecting or enforcing
Lender's rights hereunder, in each case in accordance with the terms of this
Agreement, shall be borne and paid by Grantor on demand by Lender and until so
paid shall be added to the principal amount of the Obligations and shall bear
interest at the highest rate applicable to Revolving Credit Loans from time to
time under the Loan Agreement.

      12. Subject to any applicable terms of the Loan Agreement, Grantor shall
have the duty to prosecute diligently any trademark application with respect to
the Schedule A Trademarks pending as of the date of this Agreement or thereafter
to preserve and maintain all rights in the Schedule A Trademarks, and upon
reasonable request of Lender, Grantor shall make federal application on
registrable but unregistered trademarks belonging to Grantor. To the extent that
Grantor has the duty or right to make any trademark applications under the
License Agreement, Grantor shall have the same


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<PAGE>   5
duties with respect to the Schedule B Trademarks as stated in the previous
sentence. Any reasonable expenses incurred in connection with such applications
shall be borne by Grantor. Grantor shall not abandon any Trademark without the
prior written consent of the Lender, which consent shall not unreasonably be
withheld.

      13. Grantor shall have the right to bring suit in its own name to enforce
the Trademarks, in which event Lender may, if Grantor reasonably deems it
necessary, be joined as a nominal party to such suit if Lender shall have been
satisfied, in its sole discretion, that it is not thereby incurring any risk of
liability because of such joinder. Grantor shall promptly, upon demand,
reimburse and indemnify Lender for all damages, reasonable costs and expenses,
including attorneys' fees, incurred by Lender in the fulfillment of the
provisions of this paragraph.

      14. If an Event of Default is outstanding under the Loan Agreement, Lender
may, without any obligation to do so, complete any obligation of Grantor
hereunder, in Grantor's name or in Lender's name, but at Grantor's expense, and
Grantor hereby agrees to reimburse Lender in full for all reasonable costs and
expenses, including attorneys' fees, incurred by Lender in protecting, defending
and maintaining the Trademarks.

      15. No course of dealing between Grantor and Lender nor any failure to
exercise, nor any delay in exercising, on the part of Lender, any right, power
or privilege hereunder, shall operate as a waiver thereof, and all of Lender's
rights and remedies with respect to the Trademarks and the Grantor's rights
under the License Agreement, whether established hereby or by the Loan
Documents, or by any other future agreements between Grantor and Lender or by
law, shall be cumulative and may be exercised singularly or concurrently.

      16. The provisions of this Agreement are severable and the invalidity or
unenforceability of any provision herein shall not affect the remaining
provisions which shall continue unimpaired and in full force and effect.

      17. This Agreement shall inure to the benefit of and be binding upon the
respective successors and permitted assigns of the parties.

      18. This Agreement shall be governed by and construed in conformity with
the laws of the Commonwealth of Pennsylvania without regard to its otherwise
applicable principles of conflicts of laws.

      19. GRANTOR AND LENDER EACH WAIVE ANY AND ALL RIGHTS IT MAY HAVE TO A JURY
TRIAL IN CONNECTION WITH ANY LITIGATION, PROCEEDING OR COUNTERCLAIM ARISING WITH
RESPECT TO RIGHTS AND OBLIGATIONS OF THE PARTIES UNDER THIS AGREEMENT.

                 [REMAINDER OF PAGE LEFT INTENTIONALLY BLANK]


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<PAGE>   6
      IN WITNESS WHEREOF, the parties hereto have executed this Trademark
Security Agreement the day and year first above written.


                              IGEN, INC.



                              By: /s/ Robert E. McDaniel
                                  ------------------------------------------

                              Name:   Robert E. McDaniel
                                      --------------------------------------
                              Title:  Secretary
                                      --------------------------------------

                                      S-1
<PAGE>   7
                            CORPORATE ACKNOWLEDGMENT


UNITED STATES OF AMERICA      :
STATE OF                      : SS
COUNTY OF                     :



      On this ________ of October, 1999, before me personally appeared
___________________, to me known and being duly sworn, deposes and says that
s/he is ________________________of IGEN INC.; that s/he signed the Agreement
thereto as such officer pursuant to the authority vested in him by law; that the
within Agreement is the voluntary act of such corporation; and s/he desires the
same to be recorded as such.






                                          __________________________________
                                          Notary Public

                                          My Commission Expires:


                                      -7-
<PAGE>   8
                                    Exhibit I

                              TRADEMARK ASSIGNMENT


      WHEREAS, IGEN, INC. ("Grantor") is the registered owner of the United
States trademarks, tradenames and registrations listed on SCHEDULE "A" attached
hereto and made a part hereof (the "Trademarks"), which are registered in the
United States Patent and Trademark Office; and

      WHEREAS, _____________________________ ("Grantee"), having a place of
business at ___________________________________________________, is desirous
of acquiring said Trademarks;

      NOW THEREFORE, for good and valuable consideration, receipt of which is
hereby acknowledged, and intending to be legally bound hereby, Grantor, its
successors and assigns, does hereby transfer, assign and set over unto Grantee,
its successors, transferees and assigns, all of its present and future right,
title and interest in and to the Trademarks and all proceeds thereof and all
goodwill associated therewith issued under and pursuant to the Power of
Attorney.

      IN WITNESS WHEREOF, the undersigned has caused this Trademark Assignment
to be executed as of the 29th day of October, 1999.



                                          __________________________________



                                    By:   _________________________________
                                                Attorney-in-fact


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<PAGE>   9
STATE OF                            :
                                    :  S.S.
COUNTY OF                           :


      On this 29th day of October, 1999, ____ before me, a Notary Public for the
said County and State, personally appeared known to me or satisfactorily proven
to me to be attorney-in-fact on behalf of IGEN, INC. ("Grantor") and s/he
acknowledged to me that s/he executed the foregoing Trademark Assignment on
behalf of Grantor, and as the act and deed of Grantor for the purposes therein
contained.

      IN WITNESS WHEREOF, I hereunto set my hand and official seal.





                                          __________________________________
                                                      Notary Public



My Commission Expires:


__________________________________


                                      -9-
<PAGE>   10
                                POWER OF ATTORNEY

      IGEN, INC., ("Grantor"), hereby authorizes FLEET CAPITAL CORPORATION, its
successors and assigns, and any officer or agent thereof (collectively,
"Lender") as Grantor's true and lawful attorney-in-fact, with the power to
endorse Grantor's name on all applications, assignments, documents, papers and
instruments necessary for Grantee to enforce and effectuate its rights under a
certain Trademark Security Agreement between Grantor and Lender dated the date
hereof (as it may hereafter be supplemented, restated, superseded, amended or
replaced, the "Trademark Agreement"), including, without limitation, the power
to use the Trademarks (as defined in the Trademark Agreement) and listed on
SCHEDULE A attached hereto and made a part hereof, to grant or issue any
exclusive or nonexclusive license under the Trademarks to anyone else, or to
assign, pledge, convey or otherwise transfer title in or dispose of the
Trademarks, in each case subject to the terms of the Trademark Agreement.

      This Power of Attorney is given and any action taken pursuant hereto is
intended to be so given or taken pursuant to and subject to the provisions of a
certain Loan and Security Agreement bearing even date herewith among Grantor and
Lender, as each document may be hereinafter supplemented, restated, superseded,
amended or replaced.

      Grantor hereby unconditionally ratifies all that such attorney shall
lawfully do or cause to be done by virtue hereof and in accordance with the
terms of the Trademark Agreement.

      This Power of Attorney shall be irrevocable for the life of the Trademark
Agreement.

      IN WITNESS WHEREOF, the Grantor has executed this Power of Attorney, this
29th day of October, 1999


                                   IGEN, INC.



                                   By: /s/ Robert E. McDaniel
                                      ---------------------------------

                                   Name: Robert E. McDaniel
                                      ---------------------------------

                                   Title: Secretary
                                      ---------------------------------


                                      -10-
<PAGE>   11
                            CORPORATE ACKNOWLEDGMENT


UNITED STATES OF AMERICA      :
STATE OF                      : SS
COUNTY OF                     :


      On this 29th of October, 1999 personally appeared ____________________, to
me known and being duly sworn, deposes and says that s/he is ______________of
IGEN, INC., the Grantor corporation described in the foregoing Power of
Attorney; that s/he signed the Power of Attorney as such officer pursuant to the
authority vested in her/him by law; that the within Power of Attorney is the
voluntary act of such corporation; and s/he desires the same to be recorded as
such.





                                          _____________________________________
                                          Notary Public

                                          My Commission Expires:


                                      -11-
<PAGE>   12
                                  SCHEDULE "A"

                                   TRADEMARKS

<TABLE>
<CAPTION>
Name/Title              Registration Number                 Date of Registration
----------              -------------------                 --------------------
<S>                     <C>                                 <C>

</TABLE>


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