Blue Crab Nano-Sensor Detects Dangers

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.

Crab lovers can hold on to their mallets -- 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 university's 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).

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 (see photo to left), that 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).