Microspectroscopic molecular detection based on liquid-liquid interface-assisted optical tweezers

2019 Fiscal Year Final Research Report

• Project/Area Number: 18K14254
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 34020:Analytical chemistry-related
• Research Institution: Osaka City University
• Principal Investigator: Shoji Tatsuya 大阪市立大学, 大学院理学研究科, 講師 (90701699)
• Project Period (FY): 2018-04-01 – 2020-03-31
• Keywords: 光ピンセット / 液液界面 / 顕微蛍光分光法 / 分子濃縮

Outline of Final Research Achievements

Optical trapping (OT) at a liquid/liquid (L/L) interface involves a wealth of chemical interest. However, it has been limited so far. We demonstrated optical trapping and micro-assembly formation of polystyrene beads at a L/L interface. We found that polystyrene microspheres were efficiently trapped at a water/hexane interface. During near-infrared laser irradiation, numerous particles were trapped even at the outside of the irradiation area. These unique trapping behaviors indicated that a L/L interface has some assisted effects in OT. The effect would be caused by a light propagation among the trapped polystyrene beads and by suppresses the diffusive motion of the beads at the interface by the surface tension forces.
We named this novel OT at L/L interface “LiLiI-OT (Liquid/Liquid Interface-assisted OT)” We believe that LiLiI-OT will become a powerful manipulation technique toward analytical chemistry.

Free Research Field

分析化学

Academic Significance and Societal Importance of the Research Achievements

金や銀などの貴金属ナノ粒子に共鳴光を照射すると、単分子レベルの高感度分子検出が可能である。しかしながら、検出できる分子に成約がある。そこで水と油のような二つの液体から成る界面で貴金属ナノ粒子と高分子を光の力により捕まえ、水層と油層中に微量に溶解した有機分子を高感度に検出する新たな分析手法の開発を目指し研究を進めた。その結果、このような液液界面を利用すると貴金属ナノ粒子を効率よく捕捉することに成功した。今後、この手法を発展することで単分子レベルの高感度化を目指す。