Detecting blood-circulating cancer DNA biomarkers by PCR amplification and deep-sequencing is a form of liquid biopsy and has been done routinely for treatment monitoring. However, it is not a viable approach for early cancer detection when there are not sufficient cancer DNA in the blood. Current ctDNA-based liquid biopsy is also time consuming and costly. I will talk about our alternative photonic approach that do not require PCR or DNA sequencing. Plasmonic nanoparticles (NP) permit light-induced free electron resonance, also known as localized surface plasmon resonance (LSPR). Recent advances in nanofabrication and synthesis facilitate the fine-tuning of LSPR properties in a wide spectral range for applications in sensing, imaging, energy conversion and catalysis. Arrayed nanoplasmonics is an interesting phenomenon when a group of plasmonic NP interact with one another. Prominent examples to date include near- and far-field coupling, lattice plasmon resonance (LPR), Fano resonance, and etc. Spatial regularity and precision in highly ordered arrangements or arrays is considered a key prerequisite. Previous studies also suggested that radiative coupling is nil in disordered array arrangements. In this talk, I will show that the stringent requirements on spatial precision and regularity can be significantly relaxed when plasmonic NP are strongly coupled, thereby allow the use of less-ordered plasmonic arrays fabricated by low-cost nanosphere lithography (NSL). I will discuss several potential applications of detecting DNA and small extracellular vesicles (aka, exosomes) on various arrayed nanoplasmonic sensors.

Biography: Wei-Chuan Shih is Cullen Engineering Professor of Electrical Engineering, Biomedical Engineering, Materials Science & Engineering, and Chemistry at the University of Houston (UH). He earned his Ph.D. from MIT Spectroscopy Lab under the tutelage of Prof. Michael S. Feld and joined University of Houston after a stint as Schlumberger research fellow. He received MIT Martin Fellowship, NSF CAREER Award, NASA Early CAREER Faculty Award, and several research and innovation awards at UH. He has published 82 journal paper and 64 conference abstracts/papers and holds 18 granted US patents. He is Fellow of SPIE, and serves as Associate Editor for Optica Optics Express and SPIE Journal of Nanophotonics. His research interests are biophotonics, nanobiophotonics, imaging & spectroscopy, micro/nanofabrication, and machine learning. His current research focus is on exosome-based cancer and Alzheimer’s disease diagnostics supported by NIH and DoD. Dr. Shih has started multiple companies based on his technologies. Most recently, he co-founded Seek Diagnostics to commercialize nanobiophotonic liquid biopsy technology.

Website: http://www.ee.uh.edu/faculty/shih