[1] Univ Calif Los Angeles, Dept Bioengn, Los Angeles, CA 90095 USA
[2] Natl Univ Singapore, Dept Biomed Engn, 4 Engn Dr 3, Singapore 117583, Singapore
[3] Univ Calif Los Angeles, Dept Neurobiol, Los Angeles, CA 90095 USA
[4] Univ Calif Los Angeles, Calif Nanosyst Inst, Los Angeles, CA 90095 USA
[5] Univ Calif Los Angeles, Jonsson Comprehens Canc Ctr, Los Angeles, CA 90095 USA