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                                                                   EXHIBIT 10.28




                      AMENDED AND RESTATED PROMISSORY NOTE

$383,885.00                                                     Portland, Oregon
                                                                February 8, 2002

         THIS AMENDED AND RESTATED PROMISSORY NOTE AMENDS AND RESTATES THAT
PROMISSORY NOTE AND SECURITY AGREEMENT DATED DECEMBER 15, 1999.

         FOR VALUE RECEIVED, MicroHelix, Inc., successor by merger to mHL
Development Co., Inc. ("Maker") promises to pay to the order of Richard G. Sass
("RGS") in lawful money of the United States of America, the principal amount of
Three Hundred Eighty-Three Thousand Eight Hundred Eighty-Five Dollars
($383,885.00) together with interest on such amount from February 8, 2002, at
the interest rate of seven and one-half percent (7.5%) per annum (the "Interest
Rate"). Interest shall be computed on the outstanding principal amount on the
basis of a 365-day year and actual days elapsed.

         Maker shall pay monthly payments of interest only commencing March 1,
2002. In addition, Maker shall make a payment in the amount of $43,885.00 on or
before March 31, 2003, to be applied to the principal amount of this Note. Maker
shall pay in full the aggregate unpaid principal amount of this Note, together
with all accrued and unpaid interest thereon, on or before December 31, 2004.

         This Note may be prepaid, at any time and from time to time, in whole
or in part, without penalty or premium. Any prepayment shall include accrued and
unpaid interest to the date of prepayment on the amount prepaid. All payments
shall be made directly to RGS in immediately available funds.

         In the event that RGS uses an outside attorney to construe, interpret,
or enforce any of the provisions of this Note or take any action in any
bankruptcy, insolvency or similar proceeding affecting creditors' rights
generally (including, without limitation, prosecution of a motion for relief
from stay, proposal of a Chapter 11 plan, objection to a disclosure statement or
a Chapter 11 or 13 plan, or objection to proposed use, sale or lease of
property) or in mediation or arbitration, RGS shall be entitled to recover from
Maker its reasonable attorney fees and other costs incurred regardless of
whether any legal proceeding is commenced. If any legal action, arbitration or
other proceeding is brought, the prevailing party shall be entitled to recover
its reasonable attorney fees and other costs incurred in connection therewith,
both at trial and on any appeal therefrom or petitions for review thereof.

         All parties to this Note hereby waive presentment, dishonor, notice of
dishonor, and protest. All parties to this Note hereby consent to, and the
holder of this Note is hereby expressly authorized to make, without notice, any
and all renewals, extensions, modifications or waivers of the time for or the
terms of payment of any sum or sums due under this Note, or under any documents
or instruments relating to or securing this Note, or the performance of any
covenants, conditions or agreements hereof or thereof, or the taking or release
of collateral securing this Note. The liability of all parties on this Note
shall not be discharged by any action consented to above taken by any holder of
this



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Note. The liability of all parties on this Note shall not be discharged by any
action consented to above taken by any holder of this Note.

         Maker may not assign or transfer this Note without the prior written
consent of RGS. This Note is made with reference to, and is to be construed in
accordance with, the laws of the State of Oregon, exclusive of choice of law or
conflicts of law rules or principles. Time is of the essence of this Note.

         This Note is secured by a Security Agreement of even date covering the
collateral described therein.

         Maker executes this Note as of the date first above written and
acknowledges receipt of a copy of this Note.

                                        MicroHelix, Inc., successor by merger to
                                        mHL Development Co., Inc.


                                        By:
                                          --------------------------------------
                                        Name:
                                            ------------------------------------
                                        Title:
                                             -----------------------------------


                                        Richard G. Sass



                                        ----------------------------------------
                                        Name:  Richard G. Sass
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