近赤外レーザー光に照射された金ナノ粒子のイオン電流応答に対する電解質濃度依存性

抄録

To improve the throughput of nanopore sequencers based on the well-known Coulter’s principle, novel methods using optical manipulation techniques for efficient transportation of nanoparticles into the sensing section have been proposed. Notably, we achieved successful electrical detection of both Au nanoparticles and polystyrene particles. However, the current response of Au nanoparticles exhibited conductive pulses rather than resistive pulses. The influence of light absorption of Au nanoparticles on ionic current responses requires further investigation. Au nanoparticles with a diameter of 200 nm are optically manipulated and brought into a nano-orifice using a Gaussian beam irradiated in a 0.05 × PBS electrolyte solution. When a Au particle just escapes from the nano-orifice, a conductive pulse appears in the ionic current. The conductive pulse of a Au particle in a 0.05 × PBS solution is surprisingly larger than that previously observed in a 0.5 × PBS solution. These findings underscore the relationship between the optical force and electrolyte concentration in ionic current modulations, providing a valuable insight into the single particle sensing.