Sensor on a chip: New technology holds potential for monitoring ecosystem, human health

University of Delaware researchers are developing sensors that they hope will allow real-time, in situ detection of water and air pollutants in an inexpensive and environmentally friendly manner.

In their sensor-on-a-chip research, UD professors Juejun Hu and Chaoying Ni are creating small, highly sensitive devices for detecting environmental pollutants at the single-molecule level. The technology also may have applications in biomedicine—for example, for analyzing a patient's breath to detect disease.

Juejun Hu and Chaoying Ni of UD's Department of Materials Science and Engineering are creating small, highly sensitive devices that will detect organic, inorganic and biological molecular species at low levels in the environment. The team is funded by a seed grant from the National Science Foundation's Delaware Experimental Program to Stimulate Competitive Research (EPSCoR).

"We're making nanostructures to detect chemical molecules in a very sensitive manner," said Hu, an assistant professor who is the lead researcher on the project.

With further research and development, the devices could be integrated into portable, battery-powered sensor packages, replacing more traditional molecular detectors, which require bulky and expensive equipment.

Deployed in a network in the field, an array of the small sensors could detect contamination in air, water and soil in real time and relay that information wirelessly to a computer.

A major obstacle preventing small sensors from becoming practical replacements for bulky machines is that the new technology is still less sensitive and specific in its detection than the instruments currently in use. The project aims to create sensors that overcome these obstacles.

"It's a new type of sensor," said Ni, associate professor. "It is very small and, more importantly, it is very sensitive and very specific."

Researchers discuss the sensor on a chip that can be used in environmental monitoring.

The researchers use a focused ion beam (FIB) to punch holes into a thin strip of chalcogenide glass (ChG) a few micrometers thick, or about one-tenth the width of a hair. When light passes through the strip, molecules in the environment selectively absorb one or a few particular colors of the light. The unique optical absorption signals can then be used to identify the presence and concentration of the molecules of interest. The researchers plan to group several of the tiny, chip-sized devices together to create a sensor capable of detecting multiple types of molecules.

Read more at: http://phys.org