講演情報
[16a-P01-11]Selective Formation of a Single Droplet and Aggregate of Protein Lysozyme by Optical Trapping at Solution Surface
〇(M2)Yi-Sian Chien1, Keisuke Yuzu1, Shuichi Toyouchi1, Henryk Witek1, Eri Chatani2, Hiroshi Masuhara1 (1.National Yang Ming Chiao Tung Univ., Taiwan, 2.Kobe Univ., Japan)
キーワード：
Optical Trapping、Single droplet and aggregate formation、Solution Surface
Optical trapping is a technique used to capture particles ranging from nanometers to micrometers in size via a tightly focused laser beam in a contactless manner. Our group have studied optical trapping of lysozyme under supersaturated concentration and found a single disk-like assembly which expanded outside the focal spot. In addition to lysozyme, we studied diluted alpha-synuclein trapping and successfully demonstrated a single droplet formation at air/solution interface as well. In our previous experiments of lysozyme, at high concentrations, protein molecules densely gathered in solution resulting in the formation of a single assembly. In contrast, at low concentrations, protein clusters were sparsely dispersed in the solution and underwent liquid-liquid phase separation to form a liquid droplet.
In this work, we studied optical trapping and assembling of 40 mg/mL lysozyme with 4 wt% NaCl under different buffer solution at the air/solution interface. We successfully demonstrated a single protein droplet formation under low pD value (pD 4.9) and a single protein aggregate formation under high pD value (pD 7.3). We observed that both pD 4.9 and pD 7.3 initially started from a single tiny droplet (smaller than 5 µm), which eventually grew into a single large droplet (larger than 10 µm) or aggregate, respectively. The results suggested that aggregate is originated from the droplet. Additionally, the appearance times of the droplet and the aggregate were notably different: it took only a few seconds to generate an aggregate at pD 7.3, while it took a few minutes to generate a droplet at pD 4.9. These observations confirmed that charge screening will affect the electrostatic repulsion among proteins under different pD values.
In this work, we studied optical trapping and assembling of 40 mg/mL lysozyme with 4 wt% NaCl under different buffer solution at the air/solution interface. We successfully demonstrated a single protein droplet formation under low pD value (pD 4.9) and a single protein aggregate formation under high pD value (pD 7.3). We observed that both pD 4.9 and pD 7.3 initially started from a single tiny droplet (smaller than 5 µm), which eventually grew into a single large droplet (larger than 10 µm) or aggregate, respectively. The results suggested that aggregate is originated from the droplet. Additionally, the appearance times of the droplet and the aggregate were notably different: it took only a few seconds to generate an aggregate at pD 7.3, while it took a few minutes to generate a droplet at pD 4.9. These observations confirmed that charge screening will affect the electrostatic repulsion among proteins under different pD values.