[20p-A202-1~19] 3.1 Basic optics and frontier of optics (merged with formerly 3.2 Equipment optics and materials)

▲ [20p-A202-5] Cooperative Optical Trapping Dynamics of Two Proteins at Solution Surface

〇(M2)Wei-Hsiang Chiu, Po-Wei Yi^1,2, Shuichi Toyouchi³, Roger Bresoli-Obach⁴, Johan Hofkens⁴, Eri Chatani⁵, Hiroshi Masuhara¹ (1.National Yang Ming Chiao Tung Univ.,Taiwan, 2.NAIST, Japan, 3.Osaka Metropolitan Univ., Japan, 4.KU Leuven, Belgium, 5.Kobe Univ., Japan)

Keywords:optical trapping, protein assembly, solution surface

Previously, we demonstrated that the protein lysozyme (Lys) forms a highly concentrated domain by tightly focusing a 1064 nm laser at air/D2O solution surface. To elucidate the formation mechanism of the domain, we studied simultaneous trapping of Lys with a crowding agent, polyethylene glycol . This approach is extended to cooperative trapping of two different proteins, Lys and Bovine Serum Albumin (BSA), utilizing transmission imaging and Raman micro-spectroscopy. When Lys concentration was 200 mg/mL, the domain formation is much slower compared to the supersaturation. BSA (200 mg/mL) was added there, and then, a domain could be quickly generated. By Raman micro-spectroscopy followed by a non-negative matrix factorization analysis, we obtained the temporal change of Lys and BSA concentrations at the focus in the domain. After 1 min laser irradiation, the concentration of Lys and BSA is increased and decreased, respectively. Once the trapping laser was switched off, the concentration change is partially reverted. Based on these results, cooperative, selective, and competitive processes in optical trapping of two proteins solution will be discussed.