Manipulation of Biomolecules Into Nanogap by Plasmonic Optical Excitation for Highly Sensitive Biosensing

This paper demonstrates the manipulation of DNA oligomers with 16 adenine molecules using plasmonic nanogap structure. The optical excitation caused plasmonic dielectrophoresis or/and thermophoresis of molecules to the nanogap due to huge gradient of an electric field. We confirmed the single-molecule electrical measurement using the nanogap electrodes irradiated by a He-Ne laser. We considered that the DNA oligomers were transported to the nanogap resulting in conductance change. We classified the changes in the current as step- or spike-like signals. The histogram of the stagnation time shows the peak at around 22 ms. We were able to detect the behavior of DNA oligomers.