<PAGE>   1
                                                                   EXHIBIT 10.33


                           CONVERTIBLE PROMISSORY NOTE

                                  June __, 2001

For value received, microHelix, Inc., an Oregon corporation, ("Borrower")
promises to pay __________________ (such person or its permitted transferee or
transferees being herein referred to as the "Lender") the sum of ____________
dollars ($______) plus interest thereon at the rate of 9% per annum from the
date written above until paid, all in accordance with the following terms and
conditions:

1.      TERM. The term of this Note shall expire at the close of business,
        Eastern Time, on June 30, 2003 (the "Due Date"), at which time, except
        as otherwise provided herein, the principal amount written above and all
        interest accrued thereon shall become due and payable.

2.      PAYMENTS DURING THE TERM. No payments of principal or interest shall be
        due until December 31, 2001. On December 31, 2001, March 31, 2002 and
        June 30, 2002, Borrower shall pay all accrued and unpaid interest as of
        such date. The principal hereof and additional interest hereon shall be
        payable in four equal quarterly installments of $______ payable on each
        of September 30, 2002, December 31, 2002, March 31, 2003 and June 30,
        2003.

3.      CONVERSION. If, on or before December 31, 2001, Borrower shall
        consummate a firmly underwritten public offering of equity securities
        that shall cause such securities to be listed on the NASDAQ National or
        SmallCap Markets or the American Stock Exchange (an "IPO"), the
        principal of, and accrued interest on, this Note shall be automatically
        converted into the securities sold to the public in the IPO at the rate
        of one such security (or unit consisting of more than one security) for
        each amount of such principal and accrued interest equal to the initial
        public offering price for such security or unit in the IPO.

4.      PREPAYMENT. This Note may be prepaid, in whole or in part, at any time
        after December 31, 2001 at the option of the Borrower. Any partial
        prepayment shall be applied first to interest and the balance, if any,
        shall be applied to a reduction of principal. In the event of any
        partial prepayment, the quarterly installment payments shall continue to
        become due in the amount set forth in Section 2 provided that no such
        payments shall be required after all principal and accrued interest have
        been paid. All principal and accrued interest on this note shall be
        prepaid in full within 10 business days following any equity financing
        by Borrower in which Borrower receives net proceeds of $5 million or
        more.

5.      PERMITTED TRANSFEREES. The rights of Lender under this Note are not
        transferable except as specifically provided in this Section 4. This
        Note is transferable:

        (a)    in whole, but not in part, to an entity that controls, is
               controlled by or is under common control with the transferor;


                                       1
<PAGE>   2

        (b)    in a prorata distribution to the owners of the transferor;

        (c)    by will or pursuant to the laws of descent and distribution; or

        (d)    in connection with a bona fide pledge or hypothecation of this
               Note as security for indebtedness of the Lender, or any
               foreclosure pursuant to the terms of such pledge or
               hypothecation.

6.      NOTICE. Any notice permitted or required hereby shall be deemed validly
        given if (i) sent by registered mail, return receipt requested, or by a
        recognized package delivery company that maintains a record of
        deliveries, or (ii) received at the address of the person to whom such
        notice is directed by any physical or electronic means. Any notice to
        Borrower shall be addressed to Borrower at

               16125 SW 72nd Ave.
               Portland, OR 97224
               Telephone (503) 968-1600

        or at any fax or email address maintained by Borrower for general
        corporate purposes. Any notice to Lender shall be addressed to Lender at

               ____________________

               ____________________

               ____________________
               Tel: (___) ___-_____
               Fax: (___) ___-_____

        or at any fax or email address maintained by Lender for general
        corporate purposes.

        with a copy to

               ____________________

               ____________________

               ____________________

               Tel: (___) ___-_____
               Fax: (___) ___-_____

        Any party may change addresses at which it wishes to receive notice by
        valid notice to the other parties setting forth the new address.

7.      GOVERNING LAW. This Note shall be governed by and interpreted under the
        laws of the State of Oregon, excluding provisions thereof relating to
        conflict of laws.

8.      COLLECTION COSTS. If any due and unpaid principal of or interest on this
        Note is referred for collection, or if legal action is instituted to
        collect any such amount,


                                       2