[1] Natl Univ Singapore, Fac Engn, Div Bioengn, Nanosci & Nanotechnol Initiat, Singapore 117576, Singapore
[2] Indian Inst Technol, Dept Met & Mat Engn, Madras 600035, Tamil Nadu, India
[3] Natl Univ Singapore, Dept Mech Engn, Singapore 117576, Singapore