Manipulation of biological nanomolecules by plasmonic thermophoresis

Abstract

Techniques for the analysis and manipulation of biological nanomolecules are highly required. This study investigated the manipulation behavior of the biological nanomolecules using plasmonic phenomena around gold nanostructures on substrate. When a laser light is irradiated on the gold nanostructures, localized surface plasmon resonance is excited, enabling the thermophoretic manipulation of nanoscale materials induced by the optothermal effect. In this study, substrates with gold nanostructures were fabricated by electron beam lithography, and the manipulation behavior of a protein, Dps, labeled with the fluorescent protein TGP, was observed. In the experiment, it was confirmed that the Dps was accumulated in a ring-like shape. Also, as the laser power increased, the diameter of the ring-like shape became larger. Then, the relative intensity at the center of the irradiation was decreased.