NATICK, Mass., Jan. 27, 2006 – To meet the needs of Army medics in difficult situations, a team of expert research scientists have developed an apparatus to conveniently sterilize contaminated medical equipment in the absence of electricity.  Christopher Doona of the Research, Development and Engineering Command Natick Soldier Center -Combat Feeding Directorate here, and Dave Baer of the U.S. Army Medical Research and Materiel Command Institute of Surgical Research in Fort Sam Houston, Texas, assembled a team of research scientists and engineers including Florence Feeherry, former Senior Scientists Irwin Taub and Al McManus, and professors Ken Kustin (Brandeis University), Maria Curtin (Stonehill College), and Satish Kandlikar (Rochester Institute of Technology). 

The dedicated work of the team of chemists, microbiologists, physiologists, and engineers in developing a portable chemical sterilizer has paid off. In the past year, they designed and tested three different prototype versions, submitted two patent applications to the U.S. Patent and Trademark Office, and were selected for a 2005 Department of the Army Research and Development Achievement Award for their outstanding scientific and technical excellence.

U.S. Army medics treating wounds in far-forward field stations face many challenges. Power generators are often not only unavailable, but their use is undesirable due to the noise and heat they emit. With an ample supply of sterile medical equipment, the surgeon can patch wounds and save limbs and lives, even in such a remote location. However, once a doctor's supply of clean, germ-free surgical instruments is used up, all surgery must stop. Medics can use only sterile instruments. Contaminated instruments risk spreading life-threatening infections and are useless for saving lives even in the hands of the most skilled surgeon.

Medics need a lightweight, durable, and reusable apparatus that can easily be transported and used in remote locations to conveniently sterilize contaminated medical equipment in the absence of electricity. This device must be truly portable: it should weigh 15-20 pounds, and have the size and dimensions adapted for easy carrying. And the doctor doesn't want to wait hours for fresh, sterile instruments; the sterilization process should be completed within 15-30 minutes.

The team considered the commercially available sterilization methods such as steam-autoclaving, irradiating, or fumigating, and found that each method failed to fulfill the three requirements of sterilizing contaminated medical instruments: power-free, portable, and fast-acting. The team worked together and forged an innovative new solution: a novel chemical combination activated by small

quantities of water in a specially designed lightweight plastic carry-case with sufficient capacity to sterilize an entire tray of used surgical instruments. 

To operate the portable chemical sterilizer, packets of safe chemical reagents are mixed in water to generate large amounts of germ-destroying chlorine dioxide.  Chlorine dioxide is the lethal chemical agent that was used to decontaminate the Hart Senate Office Building and the Brentwood postal facility during the anthrax (bacterial spore-former Bacillus anthracis) attacks.  In alternative treatments, chlorine dioxide could be used to decontaminate military field equipment, sanitize field-feeding equipment, or to eliminate harmful pathogens or spoilage organisms from the surfaces of fresh fruits and vegetables.  

The NSC-ISR team also developed a special aluminum pressure vessel for use in more severe environments such as high altitudes or freezing temperatures, and the chemical combination is augmented with the familiar meals-ready-to-eat heater to generate chlorine dioxide and high temperatures.  Gas scrubbers remove any excess gas so the device can be safely operated indoors while ensuring operator safety. 

The environment will not be harmed, because the chemical end-products are harmless salts that can be dissolved in water and easily disposed.

While developing the concept of a prototype was truly an innovative scientific achievement, moving this invention from the laboratory bench-top to an actual field setting requires validation testing to ensure its effectiveness on killing common infectious bacteria, such as Staphylococcus aureus, Escherichia coli, Listeria monocytogenes and Bacillus-type spores.

Doona was eager to demonstrate that practical results could readily be achieved with the lightweight plastic carry-case.

"I was delighted that tests in the carry-case model with exposure times as short as 15 minutes left the microbiologist searching in vain for any signs of live bacteria," said Doona.  "It was one time when a negative result was purely positive." 

The Army and regulatory agencies demand nothing less than 100 percent killing of these harmful pathogenic bacteria, and the PCS satisfies this demand.

Currently further tests and evaluations of all aspects of this apparatus are under way to determine its optimal design for commercialization.

With this truly portable, rapid-acting field sterilizer at the ready, far-forward teams will be better able to maintain their supply of fresh, sterilized instruments, and the highly skilled Army doctors will be better prepared to react to medical emergencies and protect the health and lives of today's warfighter confronting a hostile combat environment.