Not Just for Eatin': Blue Crab Nano-Sensor Detects Dangerous Substances

Jul 26, 2006, 01:00 ET from University of Maryland A. James Clark School of Engineering

    COLLEGE PARK, Md., July 26 /PRNewswire/ -- A substance found in crab
 shells is the key component in a nanoscale sensor system developed by
 researchers at the University of Maryland's A. James Clark School of
 Engineering. The sensor can detect minute quantities of explosives,
 bioagents, chemicals, and other dangerous materials in air and water,
 potentially leading to security and safety innovations for airports,
 hospitals, and other public locations.
     Clark School engineers are using a substance called chitosan
 (pronounced "kite-o-san"), found in the shells of the Chesapeake Bay's
 famous blue crab, to coat components of the microscopic sensor system.
     Crab lovers can hold on to their mallets -- the crabs do not need to be
 harvested specifically for this purpose. The material is extracted from the
 crab shell waste.
     Reza Ghodssi, associate professor in the Clark School's Department of
 Electrical and Computer Engineering and the Institute for Systems Research
 (ISR), and a member of the Maryland NanoCenter, is one of the investigators
 leading the project. He is joined by a multidisciplinary group: Gary
 Rubloff from ISR and the NanoCenter, Bill Bentley from the Fischell
 Department of Bioengineering and Greg Payne from the University of Maryland
 Biotechnology Institute (UMBI).
     "Chitosan is interesting because it's a biological compound that can
 interact with a wide variety of substances, and also work well in a
 complex, sensitive device," Ghodssi says.
     Ghodssi's graduate students, Nathan Siwak, Stephan Koev, Jonathan McGee
 and Mike Fan, are helping to develop the nanoscale "system on a chip." It
 employs multiple miniature vibrating cantilevers, similar to diving boards,
 which are coated with chitosan, plus optical sensing technology that can
 see when the cantilevers' vibrations change (such devices are called micro-
 electro-mechanical systems or MEMS). Different cantilevers can detect
 different substances and concentrations. When a targeted substance enters
 the device from the air or water, the chitosan on a specific cantilever
 interacts with the substance and causes that cantilever's vibration to
 change its characteristics. The optical sensing system sees the vibration
 change and indicates that the substance has been detected.
     Ghodssi and his collaborators have recently submitted a proposal to the
 National Institutes of Health (NIH) to develop a sensor system to detect
 the presence of avian flu.
     The technology was developed and initially tested at the Laboratory for
 Physical Sciences (LPS) in College Park, Md., and it is currently sponsored
 by LPS and the National Science Foundation (NSF).
     "This is an exciting and complex microsystem that bridges biotechnology
 and nanotechnology to address critical needs of homeland security
 applications. My colleagues and I are expecting this work to become a
 product in the near future," says Ghodssi, who has to date filed for six
 patents on the technology. Parts of this research were recently featured in
 the Journal of Micromechanics & Microengineering in April 2006 and the
 journal Biomacromolecules in November 2005.
     More About Chitosan
     Chitosan is derived from chitin, one of nature's most abundant
 biological compounds. Chitin makes up the shells of crabs and other
 crustaceans, insects, zooplankton and even the cell walls of mushrooms. It
 is both a polymer (a large molecule composed of repeating units) and
 produced by living things (biological). Chitin and its derivative chitosan
 are thus known as biopolymers. The researchers purchase chitosan in a
 purified, flake form from scientific supply companies.
     Helpful Links
     MEMS Sensors and Actuators Lab (MSAL) website:
     Prof. Reza Ghodssi's homepage:
     Maryland NanoCenter:
     University of Maryland Biotechnology Institute:
     M. W. Pruessner, N. Siwak, K. Amarnath, S. Kanakaraju, W.-H. Chuang and
 R. Ghodssi, "End-coupled Optical waveguide MEMS Devices in the Indium
 Phosphide Material System," Journal of Micromechanics and Microengineering,
 Vol. 16, pp. 832-842, April 2006.
     H. Yi, L-Q Wu, W. E. Bentley, R. Ghodssi, G. W. Rubloff, J. N. Culver,
 and G. F. Payne, "Biofabrication with Chitosan," Journal of
 Biomacromolecules, Vol. 6, No. 6, pp. 2881-2894, 2005.
     About the A. James Clark School of Engineering
     The Clark School of Engineering, situated on the rolling, 1,500-acre
 University of Maryland campus in College Park, Md., is one of the premier
 engineering schools in the U.S.
     The Clark School's graduate programs are collectively the fastest
 rising in the nation. In U.S. News & World Report's annual rating of
 graduate programs, the school is 15th among public and private programs
 nationally, 9th among public programs nationally and first among public
 programs in the mid- Atlantic region. The School offers 13 graduate
 programs and 12 undergraduate programs, including two degree programs
 tailored for working professionals and one certification program.
     The school is home to one of the most vibrant research programs in the
 country. With major emphasis in key areas such as communications and
 networking, nanotechnology, bioengineering, reliability engineering,
 project management, intelligent transportation systems and space robotics,
 as well as electronic packaging and smart small systems and materials, the
 Clark School is leading the way toward the next generations of advanced
 engineering technology.
     Visit the Clark School homepage at
     About UMBI
     With research centers in Baltimore, Rockville, and College Park, the
 University of Maryland Biotechnology Institute is the newest of 13
 institutions forming the University System of Maryland. UMBI has 85 ladder-
 ranked faculty and a 2006 budget of $60 million. Celebrating the
 institution's 20th year of service to Maryland and the world, UMBI is led
 by microbiologist and former biotechnology executive Dr. Jennie C.
 Hunter-Cevera. For more information visit

SOURCE University of Maryland A. James Clark School of Engineering