OPGN OpGen Inc

PROXY STATEMENT AND 2016 ANNUAL REPORT ON FORM 10-K
ARE AVAILABLE AT:

http://www.pstvote.com/opgen2017

Dear Stockholder:

The Annual Meeting of Stockholders of OpGen, Inc. has been called to consider and act upon the following matters:

•  Ratification of the appointment of CohnReznick LLP as OpGen’s independent registered public accounting firm for the fiscal year ending December 31, 2017.

Our Board of Directors recommends a vote “FOR” proposals 1-2.

Complete proxy materials, including the proxy card, are available to you on-line at http://www.pstvote.com/opgen2017 or upon your request by e-mail or first-class mail.  We encourage you to access and review all of the important information      contained in the proxy materials before voting.

This is not a ballot.  You cannot use this notice to vote your shares.   You may vote on-line, by mail or in person.  If you wish to vote on-line, you will need your “Control Number” (which can be found in the bottom right hand corner of this notice) and the web address, all of which will be included with or on the proxy card located on the Internet website stated above or mailed to you at your request.  No other personal information will be required in order to vote in this manner.  If you wish to vote by mail, simply print out the proxy card located on the Internet website stated above, mark the proxy card accordingly, sign and return it to us at the address indicated on the proxy card.  If you wish to vote in person at the Annual Meeting of Stockholders, simply check the box on the proxy card that you plan to attend.  Your proxy card will not be used if you vote in person

Control Number:      

Important Notice Regarding the Availability of Proxy Materials

for the Stockholder Meeting To Be Held on June 8, 2017

(1) This communication presents only an overview of the more complete proxy materials that are available to you on the Internet.  We encourage you to access and review all of the important information contained in the proxy materials before voting.

(2) The Proxy Statement and 2016 Annual R eport on Form 10-K are available at http://www.pstvote.com/opgen2017 .

(3) If you want to receive a paper or e-mail copy of these documents, you must request one.  There is no charge to you for requesting a copy.  Please make your request for a copy as instructed below on or before May 25, 2017 to facilitate timely delivery, otherwise you will not receive a paper or e-mail copy.  

To request a paper copy of these items:

Please clearly identify: (i) the items you are requesting; (ii) OpGen, Inc.; (iii) your name along with the Control Number located in the lower right hand corner of this notice and (iv) the name and address to which the materials should be mailed.

Control Number:      

*** Exercise Your Right to Vote *** Important Notice Regarding the Availability of Proxy Materials for the Shareholder Meeting to Be Held on June 08, 2017 OPGEN INC Meeting Information Meeting Type: Annual Meeting For holders as of: April 20, 2017 B BROKER LOGO HERE Date: June 08, 2017 Location: Ballard Spahr LLP 1909 K Street, NW Washington, DC 20006 Time: 11:00 AM EST A R C O D E Return Address Line 1 Return Address Line 2 Return Address Line 3 51 MERCEDES WAY EDGEWOOD NY 11717 Investor Address Line 1 Investor Address Line 2 Investor Address Line 3 Investor Address Line 4 Investor Address Line 5 John Sample 1234 ANYWHERE STREET ANY CITY, ON A1A 1A1 1234567 1234567 1234567 1234567 1234567 1234567 You are receiving this communication because you hold shares in the above named company. This is not a ballot. You cannot use this notice to vote these shares. This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. You may view the proxy materials online at www.proxyvote.com or easily request a paper copy (see reverse side). We encourage you to access and review all of the important information contained in the proxy materials before voting. See the reverse side of this notice to obtain proxy materials and voting instructions. Broadridge Internal Use Only Job # Envelope # Sequence # # of # Sequence #

Before You Vote How to Access the Proxy Materials Proxy Materials Available to VIEW or RECEIVE: 1. Annual Report/10K Wrap 2. Notice & Proxy Statement How to View Online: Have the information that is printed in the box marked by the arrow following page) and visit: www.proxyvote.com. How to Request and Receive a PAPER or E-MAIL Copy: (located on the If you want to receive a paper or e-mail copy of these documents, you must request one. There is NO charge for requesting a copy. Please choose one of the following methods to make your request: 1) BY INTERNET: www.proxyvote.com 2) BY TELEPHONE: 1-800-579-1639 3) BY E-MAIL*: sendmaterial@proxyvote.com * If requesting materials by e-mail, please send a blank e-mail with the information that is printed in the box marked by the arrow g (located on the following page) in the subject line. Requests, instructions and other inquiries sent to this e-mail address will NOT be forwarded to your investment advisor. Please make the request as instructed above on or before May 25, 2017 to facilitate timely delivery. How To Vote Please Choose One of the Following Voting Methods Vote In Person: If you choose to vote these shares in person at the meeting, you must request a "legal proxy." To do so, please follow the instructions at www.proxyvote.com or request a paper copy of the materials, which will contain the appropriate instructions. Many shareholder meetings have attendance requirements including, but not limited to, the possession of an attendance ticket issued by the entity holding the meeting. Please check the meeting materials for any special requirements for meeting attendance. Vote By Internet: To vote now by Internet, go to www.proxyvote.com. Have the information that is printed in the box marked by the arrow g available and follow the instructions. Internal Use Only Vote By Mail: You can vote by mail by requesting a paper copy of the materials, which will include a voting instruction form.

Voting items The Board of Directors recommends that you vote FOR the following: 1. Election of Directors Nominees 01 Evan Jones 02 Harry J. D'Andrea 03 Timothy J.R. Harris 04 Laurence R. McCarthy 05 Tina S. Nova 06 David M. Rubin 07 Misti Ushio B The Board of Directors recommends you vote FOR the following proposal(s): A R 2 Ratification of the appointment of CohnReznick LLP as the Company's independent registered public accounting firm for the fiscal year ending December 31, 2017. C O NOTE: Such other business as may properly come before the meeting or any adjournment thereof. D E 23456789012 12345678901 123456789012 12345678901 123456789012 12345678901 123456789012 12345678901 123456789012 12345678901 12345678901 Broadridge Internal Use Only xxxxxxxxxx xxxxxxxxxx Cusip Job # Envelope # Sequence # # of # Sequence #

Reserved for Broadridge Internal Control Information Voting Instructions THIS SPACE RESERVED FOR LANGUAGE PERTAINING TO BANKS AND BROKERS AS REQUIRED BY THE NEW YORK STOCK EXCHANGE Broadridge Internal Use Only THIS SPACE RESERVED FOR SIGNATURES IF APPLICABLE # o Job # Envelope # Sequence # f # Sequence #