BEDFORD, MA
September 23, 2005

Sionex Corporation, a high technology company focused on commercializing breakthrough chemical and biological sensor chips and systems based on its proprietary microDMx ™ detection technology, today announced that it has been named a Rising Star in Deloitte's Technology Fast 50 program for New England.
The Rising Star award is a special designation for fast-growth technology companies that have been in business three to four years and are part of the New England Technology Fast 50 program, which ranks the fifty fastest growing technology companies headquartered in New England. Rankings are based on the percentage of growth in fiscal year revenues over three years (2002 to 2004). This year's New England Technology Fast 50 program is co-presented by Deloitte & Touche LLP, one of the nation's leading professional services firms and the legal firm, Wilmer Cutler Pickering Hale and Dorr.

"We are honored and pleased to be recognized by Deloitte as a Rising Star for our strong performance," said Wes Davis, president and CEO of Sionex. "We look forward to continued strong top line growth in the coming year as more OEM companies such as Thermo Electron (NYSE:TMO) and Varian (Nasdaq:VARI) incorporate Sionex's microDMx™ products into their latest detection systems for defense, homeland security and industrial applications."

Conceived at The Charles Stark Draper Laboratory and exclusively licensed to Sionex for commercialization, the microDM™ sensor is a chip-based MEMS technology capable of detecting a wide variety of chemical and biological compounds with unsurpassed sensitivity and selectivity.

About the Fast 50 Program
To qualify for the Technology Fast 50 Rising Star program, companies must have had operating revenues of at least $50,000 in 2002 and $1,000,000 in 2004. and must be a public or private company headquartered in North America. The company must also be a "technology company", defined as owning proprietary technology that contributes to a significant portion of the company's operating revenues (using other companies' technology in a unique way does not qualify) and/or devoting a significant proportion of revenues to research and development of technology.

The New England Technology Fast 50 Program is co-sponsored by Wilmer Cutler Pickering Hale and Dorr and is supported by the American Stock Exchange and Mass High Tech.

About Sionex Corporation
Sionex Corporation is a high technology company focused on commercializing breakthrough chemical and biological sensor chips and systems based on its proprietary microDMx™ detection technology. Sionex maintains its worldwide headquarters and laboratories in Bedford, Massachusetts, close to Boston with its commercial, technology and communications infrastructure. The Company is privately held and was founded in 2001 with patented technology exclusively licensed from The Charles Stark Draper Laboratory. Additional information about Sionex Corporation is available at www.sionex.com or by calling 781-457-5400 or fax to 781-457-5399.

About Deloitte
Deloitte, one of the nation's leading professional services firms, provides audit, tax, financial advisory services and consulting through nearly 30,000 people in more than 80 U.S. cities. Known as an employer of choice for innovative human resources programs, the firm is dedicated to helping its clients and its people excel. "Deloitte" refers to the associated partnerships of Deloitte & Touche USA LLP (Deloitte & Touche LLP and Deloitte Consulting LLP) and subsidiaries. Deloitte is the US member firm of Deloitte Touche Tohmatsu. For more information, please visit Deloitte's web site at http://www.deloitte.com/us.

EDITORIAL CONTACTS:
Anthony D. Bashall
(781) 457-5407
tbashall@sionex.com

Agency Contact:
Doug Forsyth, Alchymia Communications® LLC
(541) 482-8744
df@alchymiacomm.com

Forward-looking Statement
Some statements in this announcement constitute forward-looking statements. Forward-looking statements involve known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements of Sionex Corporation to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements. There can be no assurance that the forward-looking statements included in this announcement will prove to be accurate. In light of the significant uncertainties inherent in the forward-looking statements included herein, the inclusion of this information should not be regarded as a representation by the Company or any other person that the objectives and plans of the Company will be achieved.

microDMx™ is a trademark of Sionex Corporation.