Yu's Printed Paper Sensors Talk Wins GRID Session

Fischell Department of Bioengineering graduate student Wei W. Yu, advised by Assistant Professor Ian White, won the "Technology in the 21st Century" division at the University of Maryland's 2011 Graduate Research and Interaction Day (GRID). Yu took first place for his presentation of a technique that employs an ordinary inkjet printer to make an inexpensive biosensor component for use in surface-enhanced Raman spectroscopy (SERS).

GRID, which is run by the Graduate Student Government, is a campus-wide event in which graduate students from all parts of the university present and discuss their work with faculty and fellow students, enabling them to receive feedback from a broader audience and perfect their conference presentation skills. Participants make oral and poster presentations that are judged in a variety of categories by faculty, postdoctoral fellows, administrators, and other specialists from around campus.

Yu's talk, "Inkjet Printed Paper Sensors for Chemical and Biomolecular Analysis," explained that while market for biosensors is growing rapidly, current technology limits their wider use. Lab-on-a-chip solutions are popular and state-of-the-art, but complicated, costly, and fragile. SERS, a highly-sensitive technique that uses a laser to detect the presence of mere molecules, is also effective, but the fabrication of one of its key components, a nanopaticle-laced substrate used to amplify the signals generated by the laser, is technically difficult to create, and pre-made examples are both expensive and have a shelf life of only a few days.

Yu and White's goal was to create a sensitive, portable and inexpensive biosensor that requires no expertise to manufacture and can be used in a variety of applications, including the detection of food contamination, infections, cancer, pesticides, DNA, or even explosives. To accomplish this, they printed their sensors in silver nanoparticle ink on hydophobically pretreated paper using a consumer-grade inkjet printer. Using the paper substrate in conjunction with a portable Raman spectroscopy system, they successfully identified the presence of target Rhodamine 6G tracer dye molecules present in quantities as low as 10 attomoles.

"The fabrication method is extremely simple," says Yu. "Additionally, we have leveraged the ability to modify paper to allow for microfluidic techniques such as small sample requirements and analyte concentration."

Published April 25, 2011