Wei-Heng Shih
Department of Materials Science and Engineering, Drexel University

Wednesday, November 9, 2016 3:35pm - 4:25pm
103 Leonhard Building

We have developed a method of coating Mg(OH)2 layer on Nb2O5 particles that facilitated the direct, one-step, sintering of piezoelectric lead magnesium niobate-lead titanate (PMN-PT) freestanding sheets. The piezoelectric freestanding sheets were used to develop a novel Piezoelectric Plate sensor (PEPS). By immobilizing receptors specific to target antigens on the PEPS surface, binding of target antigens such as cells, viruses, proteins, and DNA in various liquid environments to the receptor on the sensor surface causes the PEPS resonance frequency to shift. For example, PEPS can rapidly (< 30 min) detect double-stranded DNA at a concentration of 60 copies/ml point mutation in the background of 1000 times wild type in urine or serum and genetic signature of bacteria at 150 copies/ml in stool without isolation, concentration, and amplification. PEPSís enhanced detection sensitivity is related to the easy domain switching in PMN-PT layer caused by the target antigen binding to the sensor surface. .
Meanwhile, we have also developed an environmentally friendly aqueous method to synthesize aqueous quantum dots (AQDs) using mercaptopropionic acid (MPA). Due to high coverage of the capping molecules, AQDs exhibited a better than 80% conjugation efficiency and were colloidally stable. Visible and Near-infrared (NIR) AQDs were used to create a molecular probe to image cancer cells on tumors to help surgeons determine whether all cancer cells have been removed in the operating room. More recently, we studied the synthesis of organohalide perovskite materials to develop highly photoluminescent nanocrystals as well.

Wei-Heng Shih received a B.Sc. in physics in 1976 from Tsing-Hua University in Taiwan and completed his Ph.D. degree in Physics in 1984 from Ohio State University. He joined the Department of Materials Science and Engineering at Drexel University in 1991 and was promoted to Professor in 2003. His research has covered colloidal processing of ceramics; sol-gel processing of microporous and mesoporous ceramic powders; and chemical treatment of combustion wastes. His current research interests are fabrication, characterization and design of piezoelectric plate sensors and the development of environmentally friendly synthesis of photoluminescent nanocrystals (quantum dots) for biomedical and optoelectronic applications. Prof. Shih has 132 published journal papers, 32 patents and 24 patents in application. He received the 1999 Edward C. Henry Electronics Division Best Paper Award from The American Ceramic Society and was elected a Fellow of National Academy of Inventors in 2013. In Drexel University, he has received several awards including the Faculty Achievement Award, Professor of the Year, and the Research Achievement Award. His technologies have been licensed by four companies.