Document:

<PAGE>
                                                                     Exhibit 4.3

UNIT CERTIFICATE

MU
UNITS

microHelix, Inc.

CUSIP 59507X 20 0

ORGANIZED UNDER THE LAWS
OF THE STATE OF OREGON
 EACH UNIT CONSISTING OF
ONE SHARE OF COMMON STOCK, NO PAR VALUE,
 ONE CLASS A COMMON STOCK
PURCHASE WARRANT CUSIP 11111111111
AND ONE CLASS B COMMON STOCK
PURCHASE WARRANT CUSIP 11111111111

THIS CERTIFIES THAT

or registered assigns (the "Registered Holder") is the owner of the number of
Units specified above, each of which consists of one share of common stock, no
par value, of microHelix, Inc. (the "Common Stock"), one Class A Common Stock
Purchase Warrant to purchase one share of Common Stock (the "Class A Warrant")
and one Class B Common Stock Purchase Warrant to purchase one share of Common
Stock (the "Class B Warrant" and, together with the Class A Warrant, the
"Warrants"). On or prior to the Separation Time (as defined herein), the
securities evidenced by this certificate may be combined, exchanged or
transferred only as Units, and the Common Stock and Warrants evidenced by this
Certificate may not be split up, exchanged or traded separately. The Units may
separate into shares of Common Stock and Warrants as of the close of business on
__________, 2001, or at any time before that date, in the discretion of Paulson
Investment Company, Inc. (the "Separation Time"). The shares of Common Stock and
Warrants comprising the Units shall be separately tradeable commencing on the
first day after the Separation Time on which The Nasdaq SmallCap Market is open
for trading. The Warrants comprising part of the Units are issued under and
pursuant to a certain Warrant Agreement dated as of November ___, 2001 (the
"Warrant Agreement"), between the Company and UMB Bank, n.a., as Transfer Agent
(the "Transfer Agent"), and are subject to the terms and provisions contained
therein and on the face of the certificates covered thereby, to all of which
terms and provisions the holder of this Unit Certificate consents by acceptance
hereof. The Warrant Agreement provides for adjustment in the number of shares of
Common Stock to be delivered upon the exercise of Warrants evidenced hereby and
to the exercise price of such Warrants in certain events therein set forth.
Subject to the foregoing, the number of Warrants and the number of shares of
Common Stock comprising the Units are equal. Copies of the Warrant Agreement are
available for inspection at the stock transfer office of the Transfer Agent and
Registrar or may be obtained upon written request addressed to microHelix, Inc.
at 16125 SW 72nd Ave., Portland, OR 97224, Attention: Chief Financial Officer.
This Unit Certificate is not valid unless countersigned and registered by the
Transfer Agent and Registrar of the Company. IN WITNESS WHEREOF, microHelix,
Inc. has caused this Unit Certificate to be duly executed manually or in
facsimile by two of its officers thereunto duly authorized.

<PAGE>

Dated:

microHELIX, Inc.

Attest:

Secretary

By:

PRESIDENT

Countersigned and Registered:
UMB Bank, n.a.
P.O. Box 410064
Kansas City, Missouri 64141
AS TRANSFER AGENT AND REGISTRAR

By:
Authorized Signature

<PAGE>

MICROHELIX, INC.
The Registered Holder hereby is entitled, at any time after the Separation Time
(as defined on the face hereof) to exchange the Units represented by this Unit
Certificate for Common Stock Certificate(s) representing one share of Common
Stock, for each Unit represented by this Unit Certificate, one Class A Warrant
Certificate(s) representing one Class A Warrant, for each unit represented by
this Unit Certificate and one Class B Warrant Certificate(s) representing one
Class B Warrant, for each unit represented by this Unit Certificate, upon
surrender of this Unit Certificate to the Transfer Agent and Registrar together
with any documentation required by such agent.
REFERENCE IS MADE TO THE WARRANT AGREEMENT REFERRED TO ON THE FACE HEREOF, AND
THE PROVISIONS OF SUCH WARRANT AGREEMENT SHALL FOR ALL PURPOSES HAVE THE SAME
EFFECT AS THOUGH FULLY SET FORTH ON THE FACE OF THIS CERTIFICATE. COPIES OF THE
WARRANT AGREEMENT MAY BE OBTAINED UPON WRITTEN REQUEST FROM THE TRANSFER AGENT
AND REGISTRAR, UMB BANK, N.A.

The following abbreviations, when used in the inscription on the face of this
certificate, shall be construed as though they were written out in full
according to applicable laws or regulations.

TEN COM
TEN ENT
JT TEN
COM PROP
as tenants in common
as tenants by the entireties
as joint tenants with rights of
survivorship and not as tenants
in common
as community property
UNIF GIFT MIN ACT                    Custodian
                                                                          (Cust)
(minor)
                                under Uniform Gifts to Minors Act

(State)
UNIF TRF MIN ACT                     Custodian
                                                                          (Cust)
(minor)
                                under Uniform Gifts to Minors Act 3

(State)
Additional abbreviations may also be used though not in the above list.

FORM OF ASSIGNMENT
(TO BE SIGNED ONLY UPON ASSIGNMENT)
    FOR VALUE RECEIVED,                                          the undersigned
Registered Holder hereby sells, assigns and transfers unto

(Please insert social security or other
identification number of Registered Holder)

(Please Print Name and Address including Zip Code OF ASSIGNEE)

Units evidenced by the within Unit Certificate, and irrevocably constitutes and
appoints attorney to transfer this Unit Certificate on the books of microHelix,
Inc. with the full power of substitution in the premises.

Dated:

Signature:

(Signature must conform in all respects to the name of Registered Holder as
specified on the face of this Unit Certificate in every particular, without
alteration or any change whatsoever, and the signature must be guaranteed in the
usual manner.)

Signatures Guaranteed:

The signatures should be guaranteed by an eligible institution (banks,
stockbrokers, savings and loan association and credit unions with membership in
an approved signature medallion program), pursuant to S.E.C. Rule 17Ad-15.<PAGE>
                                                                   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>

        (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
<PAGE>

        the costs reasonably incurred by Lender in connection with any such
        collection process shall be paid by Borrower.

                                       microHelix, Inc.

                                       By: ____________________________________

                                       Title: _________________________________

                                       3

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00031-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00031-of-00352.parquet"}]]