a
School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore
E-mail: ktyong@ntu.edu.sg
b
Institute for Lasers, Photonics and Biophotonics, University at Buffalo, State University of New York, Buffalo, USA
E-mail: pnprasad@buffalo.edu
c
Institute of Gerontology and Geriatrics, Chinese PLA General Hospital, Beijing 100853, PR China
d
Changchun University of Science and Technology, Changchun, PR China
e
Department of Chemical and Biological Engineering, University at Buffalo, State University of New York, Buffalo, USA
f
Department of Chemistry, Korea University, Seoul, Korea
g
Department of Chemistry, University at Buffalo, State University of New York, Buffalo, USA