EXHIBIT 10.5

                             SECURED PROMISSORY NOTE

$500,000.00                                                    December 16, 2004

         FOR VALUE RECEIVED,  the  undersigned,  ALPHA INNOTECH  CORPORATION,  a
California  corporation (the "MAKER"),  hereby promise to pay to XTRANA, INC., a
Delaware  corporation (the "PAYEE" and, together with the Maker, the "PARTIES"),
in lawful  money of the United  States of  America,  the  principal  sum of FIVE
HUNDRED  THOUSAND  DOLLARS  AND NO CENTS  ($500,000.00).  Except as  provided in
Paragraph 1.2 below, no interest shall accrue on this Note.

         This  Note has been  executed  and  delivered  in  connection  with the
Agreement  and Plan of Merger,  dated as December 14, 2004,  by and among Maker,
Payee and AIC Merger  Corporation  (the "MERGER  AGREEMENT").  The Parties agree
that, in the event that Payee becomes  obligated to pay Maker a termination  fee
pursuant to Section 8.2.1 of the Merger Agreement, such termination fee shall be
deemed  to  reduce  the  principal  amount  of  this  Note  as of  the  date  of
termination.

1.       PAYMENT

         1.1      MATURITY DATE.  Upon any  termination of the Merger  Agreement
pursuant  to Section  8.1  thereof,  to the extent  outstanding  and  subject to
Section 5 hereof,  the  entire  unpaid  principal  balance  of this Note and any
accrued but unpaid  interest  thereon  shall  become due and payable on the date
which is six (6) months following the date of such termination.

         1.2      INTEREST.  In the  event  of  any  termination  of the  Merger
Agreement pursuant to Section 8.1 of the Merger Agreement,  interest will accrue
on the unpaid principal balance from time to time outstanding,  retroactive from
the date of issuance of this Note until the  principal  balance is paid in full,
at a rate of eight  percent (8%) per annum (the  "INTEREST  RATE").  In addition
(but without duplication),  from and after the occurrence of an Event of Default
(as defined  below)  interest will accrue on the unpaid  principal  balance from
time to time  outstanding,  from the date of such  occurrence  of such  Event of
Default  until  the date  when  such  Event  of  Default  is cured or until  the
principal balance is paid in full,  whichever is earlier,  at the Interest Rate.
Interest at the Interest  Rate will be  calculated on the basis of a year of 365
or 366 days, as applicable, and charged for the actual number of days elapsed.

         1.3      PREPAYMENT; APPLICATION OF PAYMENTS. Maker will have the right
to prepay all or any portion of the outstanding principal amount without premium
or penalty.  All  payments on this Note will be applied  first to the payment of
accrued interest (if any) before being applied to the payment of principal.

         1.4      MANNER OF PAYMENT. Principal,  interest, and all other amounts
due  under  this Note will be  payable,  in U.S.  dollars,  by  electronic  wire
transfer  of  immediately  available  funds  pursuant  to  written  instructions
provided to Maker by Payee. If any payment of principal or interest on this Note
is due on a day that is not a Business Day, such payment will be due on the next
succeeding  Business  Day.  "BUSINESS  DAY" means any day other than a Saturday,
Sunday or


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legal  holiday in the State of  California.  All amounts due from Maker to Payee
under this Note will be made  without  benefit of any  setoff,  counterclaim  or
other defense.

2.       DEFAULTS

         2.1      EVENTS OF DEFAULT.  The  occurrence  of any one or more of the
following  events  with  respect  to Maker will  constitute  an event of default
hereunder ("EVENT OF DEFAULT"):

                  (a)      If  Maker  fails  to pay  when  due  any  payment  of
         principal or interest on this Note and such failure  continues for five
         (5) days after such payment becomes due;

                  (b)      If Maker is in material breach of any other provision
         of this Note or any provision of the Merger Agreement,  which breach is
         not cured within ten (10) days after written  notice from Payee of such
         breach;

                  (c)      If  Maker  shall  default  in  the   performance   or
         observance of any obligation or condition with respect to  indebtedness
         in excess of  $100,000  or any other  event  shall  occur or  condition
         exist,  if the  effect  of  such  default,  event  or  condition  is to
         accelerate the maturity of such  indebtedness  or is such  indebtedness
         shall  become or be declared to be due and payable  prior to its stated
         maturity as a result of the foregoing; or

                  (d)      If  Maker,  under the laws of any  jurisdiction:  (i)
         consents  to  the  appointment  of  a  trustee,   receiver,   assignee,
         liquidator or similar official; (ii) makes a general assignment for the
         benefit of its creditors;  or (iii) institutes a proceeding,  or has an
         involuntary  proceeding  instituted  against it,  seeking a judgment of
         insolvency,   bankruptcy,   or  any  other  similar  relief  under  any
         bankruptcy,  insolvency,  or other  similar  law  affecting  creditors'
         rights that is not dismissed within ninety (90) days thereafter.

         2.2      NOTICE BY MAKER.  Maker will  notify  Payee in writing  within
five (5) days  after the  occurrence  of any  Event of  Default  of which  Maker
acquires knowledge.  If Payee is not so notified,  said failure to notify is, in
and of itself, a default.

         2.3      REMEDIES.  Subject to the  provisions of Paragraph 4.2 hereof,
upon the occurrence of an Event of Default  hereunder  (unless waived in writing
by Payee), Payee may, at its option, (a) by written notice to Maker, declare the
entire unpaid principal balance of this Note, together with all accrued interest
thereon,  immediately  due and  payable or (b)  exercise  any and all rights and
remedies  available to it under  applicable law,  including the right to collect
from Maker all sums due under this Note.  Maker will pay all costs and  expenses
incurred by or on behalf of Payee in connection with Payee's  exercise of any or
all of its rights and remedies under this Note, including attorneys' fees.

3.       SECURITY AGREEMENT.

         Maker's  obligations  under this Note are secured by the collateral set
forth in that certain Security Agreement,  dated as of the date hereof,  between
Maker and Payee (the "SECURITY AGREEMENT"). Concurrently with the termination of
this Note pursuant to Paragraph 5 below, the Security  Agreement shall terminate
and be of no further  force and effect (other than the Parties'  obligations  to
execute and deliver such documents as be necessary or appropriate to release any


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lien upon or security interest in the collateral secured thereby).  The security
interest of Maker in the  Collateral  is, and at all times shall be,  junior and
subordinate to the security interest of Senior Lender.

4.       SENIOR SUBORDINATION

         4.1      DEFINITION OF SENIOR INDEBTEDNESS.  For purposes of this Note,
the term "SENIOR  INDEBTEDNESS" shall mean the principal of and premium, if any,
and  interest on  indebtedness  of Maker under that  certain  Loan and  Security
Agreement,  dated March 9, 2004,  between Maker and BFI Business Finance ("BFI")
or its assigns ("SENIOR LENDER") and money borrowed from other commercial banks,
equipment lessors, or other financial  institutions under a secured or unsecured
line of credit, term loan or equipment lease approved by BFI.

         4.2      SUBORDINATION TO SENIOR INDEBTEDNESS. The payment of principal
and  interest  on this Note is  subordinated  in right of  payment  to the prior
payment in full of all Senior Indebtedness of Maker, whether outstanding on this
date or thereafter. In the event of any insolvency or bankruptcy proceedings, or
any  receivership,  liquidation,  reorganization,  or other similar  proceedings
relative to Maker,  or to its property,  or in the event of any  proceedings for
voluntary  liquidation,  dissolution,  or other  winding  up of Maker,  then the
holders of Senior  Indebtedness  will be entitled to receive  payment in full of
all principal and interest on all Senior  Indebtedness  before Maker is entitled
to  receive  any  payment  on account of  principal  or  interest  on this Note.
NOTWITHSTANDING  THE FOREGOING,  Maker may make scheduled  payments of principal
and interest  under this Note as provided in Section 1 hereof,  as and when such
payments  are due and  payable,  UNLESS AND UNTIL Payee and Maker have  received
written  notice from the Senior  Lender that an event of default has occurred or
been declared under either (i) the Secured Promissory Note dated August 26, 2004
in the principal amount of $300,000.00  issued by Maker to Senior Lender (unless
Maker has paid in full all of its  obligations  under  such  Secured  Promissory
Note) or (ii) that  certain Loan and  Security  Agreement,  dated March 9, 2004,
between Maker and BFI.

         4.3      SENIOR TO OTHER INDEBTEDNESS.  Subject to the prior payment in
full of the Senior Indebtedness,  Payee shall receive payments from Maker, prior
to any other creditors, until the obligations related to this Note are satisfied
in full,  PROVIDED,  HOWEVER,  that the  foregoing  will not apply to  Permitted
Indebtedness  (as defined below).  Notwithstanding  any  subordination to Senior
Indebtedness as described above,  Maker will cooperate with Payee to ensure that
payment on this Note is (to the extent commercially practicable and permitted by
applicable  law) senior to all other existing and future debt of Maker.  For the
purpose of this Paragraph 4.3, "PERMITTED  INDEBTEDNESS" shall mean indebtedness
to trade creditors incurred in the ordinary course of business.

         4.4      NO IMPAIRMENT.  This Paragraph 4 is not intended to impair, as
between Maker,  its creditors  (other than with respect to the holders of Senior
Indebtedness)  and  Payee,  the  unconditional  obligation  of  Maker to pay the
principal of and interest on this Note. Nothing in this Note shall prevent Payee
from exercising all remedies otherwise  permitted by applicable law upon default
of this  Note,  subject  to the  rights,  if any,  of the  holders of the Senior
Indebtedness in respect to cash, property,  or securities of Maker received upon
exercise of any such remedies.


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5.       TERMINATION

         This  Note,  and the  rights and  obligations  under  this Note,  shall
automatically terminate upon the Closing (as defined in the Merger Agreement).

6.       MISCELLANEOUS

         6.1      WAIVER. Maker hereby waives presentment,  demand, protest, and
notice of dishonor and protest.

         6.2      ASSIGNMENT.  Neither  Party shall assign or transfer this Note
or any of its  rights or  obligations  under  this Note  without  express  prior
written  consent of the other Party,  which  consent  shall not be  unreasonably
withheld,  conditioned  or delayed,  provided that Payee may assign this Note to
any person or entity which  acquires all or  substantially  all of the assets of
Payee without the written consent of Payee.

         6.3      SUCCESSORS.   All  of  the   terms,   agreements,   covenants,
representations,  warranties,  and conditions of this Note are binding upon, and
inure to the benefit of and are enforceable by, the Parties and their respective
successors.  If the principal business,  operations or a majority or substantial
portion of the assets of Maker are assigned,  conveyed,  allocated, or otherwise
transferred, including by sale, merger, consolidation, amalgamation, conversion,
or similar  transactions,  such receiving  person or persons will  automatically
become bound by and subject to the provisions of this Note,  and Maker,  subject
to  satisfaction  of the  provisions  of  Paragraph  6.2  above  will  cause the
receiving person or persons to expressly assume its obligations hereunder.

         6.4      NOTICES.  All  notices,  requests,  claims,  demands and other
communications  under this  Agreement  shall be in  writing  and shall be deemed
given  if  delivered  personally  or  sent by  facsimile,  electronic  mail,  or
overnight courier  (providing proof of delivery) to the parties at the following
addresses  (or at such other  address for a Party as shall be  specified by like
notice):

                  if to Maker, to:

                  Alpha Innotech Corporation
                  2401 Merced St.
                  San Leandro, CA 94577
                  Attn:  Chief Executive Officer
                  Fax: 510-483-3227

                  with a copy to (which shall not constitute notice):

                  Heller Ehrman White & McAuliffe LLP
                  4350 La Jolla Village Drive, 7th Floor
                  San Diego, CA 92122
                  Attn: Stephen Ferruolo, Esq.
                  Fax: (858) 450-8499


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                  if to Payee, to:

                  Xtrana, Inc.
                  c/o James H. Chamberlain, CEO
                  733 Spruce Meadow Place
                  Thousand Oaks, CA 91362
                  Fax:  (805) 494-0832

                  with a copy to (which shall not constitute notice):

                  Stubbs Alderton & Markiles, LLP
                  15821 Ventura Blvd., Suite 525
                  Encino, CA 91436
                  Attn: Scott Alderton, Esq.
                  Fax:  (818) 444-4520


         6.5      TIME.  Time is of the essence in the performance of this Note.


         6.6      HEADINGS.  The article and section headings  contained in this
Note are  inserted  for  convenience  only and  will not  affect  in any way the
meaning or interpretation of this Note.

         6.7      GOVERNING   LAW.  This  Note  and  the   performance   of  the
obligations  of the  Parties  hereunder  will be governed  by and  construed  in
accordance  with the laws of the State of  California,  without giving effect to
any choice of law principles.

         6.8      AMENDMENTS   AND   WAIVERS.   No   amendment,    modification,
replacement,  termination, or cancellation of any provision of this Note will be
valid,  unless the same will be in  writing  and  signed by the each  Party.  No
waiver by any Party of any  default,  Event of  Default,  misrepresentation,  or
breach of warranty or covenant  hereunder,  whether  intentional  or not, may be
deemed  to  extend to any prior or  subsequent  default,  misrepresentation,  or
breach of warranty or covenant hereunder or affect in any way any rights arising
because of any prior or subsequent such occurrence.

         6.9      SEVERABILITY.  The  provisions  of this  Note  will be  deemed
severable and the  invalidity  or  unenforceability  of any  provision  will not
affect the validity or enforceability of the other provisions  hereof;  provided
that  any  provision  of this  Note  that is  invalid  or  unenforceable  in any
situation  or in any  jurisdiction  will not  affect the  enforceability  of the
remaining  terms and provisions  hereof or the  enforceability  of the offending
term or provision in any other situation or in any other jurisdiction.

         6.10     EXPENSES. Except as otherwise expressly provided in this Note,
each Party will bear its own costs and expenses  incurred in connection with the
preparation,  execution  and  performance  of this Note,  including all fees and
expenses of agents,  representatives,  financial  advisors,  legal counsel,  and
accountants.  This  paragraph  shall not  affect  attorneys'  fees  which may be
incurred in connection  with  collection of late payments or resulting  from any
Event of Default, as described above.


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         6.11     ATTORNEYS'  FEES.  If there exists an Event of Default,  Maker
agrees to pay all costs and expenses of collection,  including  attorneys' fees,
incurred by Payee in connection therewith, whether or not suit is filed.

         6.12     CONSTRUCTION.  The Parties  have  participated  jointly in the
negotiation  and drafting of this Note. If an ambiguity or question of intent or
interpretation  arises, this Note will be construed as if drafted jointly by the
Parties and no presumption or burden of proof will arise favoring or disfavoring
any Party because of the authorship of any provision of this Note. Any reference
to any  federal,  state,  local,  or foreign law will be deemed also to refer to
such law as amended and all rules and regulations promulgated thereunder, unless
the context requires otherwise. The words "include," "includes," and "including"
will be deemed to be followed by "without  limitation."  Pronouns in  masculine,
feminine,  and neuter genders will be construed to include any other gender, and
words in the  singular  form will be  construed  to include  the plural and vice
versa, unless the context otherwise  requires.  The words "this Note," "herein,"
"hereof," "hereby,"  "hereunder," and words of similar import refer to this Note
as a whole and not to any particular  subdivision  unless  expressly so limited.
The Parties intend that each  representation,  warranty,  and covenant contained
herein  will  have  independent  significance.  If any Party  has  breached  any
representation,  warranty, or covenant contained herein in any respect, the fact
that there exists another  representation,  warranty or covenant relating to the
same subject matter (regardless of the relative levels of specificity) which the
Party has not breached will not detract from or mitigate the fact that the Party
is in breach of the first representation, warranty, or covenant.

         6.13     REMEDIES.  Except as expressly  provided  herein,  the rights,
obligations and remedies  created by this Note are cumulative and in addition to
any other  rights,  obligations  or remedies  otherwise  available  at law or in
equity.  Except as expressly provided herein,  nothing herein will be considered
an election of remedies.

         IN WITNESS  WHEREOF,  Maker has executed and delivered  this Note as of
the date first above written.

                                    MAKER:

                                    ALPHA INNOTECH CORPORATION


                                    /S/ HASEEB CHAUDHRY
                                    -----------------------------
                                    By:  Haseeb Chaudhry
                                    Its:  Chief Executive Officer


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