Redistribution of fluorescent molecules at the solid/liquid interface with total internal reflection illumination

•With total internal reflection fluorescence microscopy, it was found that moderate laser illumination on a chromatography surface could initiate a long-range electrostatic repulsion force at the liquid/solid interface.•The strength is enough to compromise the thermal diffusion of single Rhodamine B molecule in a range of several hundred nanometers normal to the liquid/solid interface.•This observation might shed new light on the development of photon modulation technique with high throughput capability.

Many intriguing physical and chemical processes commonly take place at the solid/liquid interface. Total internal reflection illumination, together with single molecule spectroscopy, provides a robust platform for the selective exploration of kinetic processes close the interface. With these techniques, it was observed that the distribution of Rhodamine B molecules close to a solid/liquid interface could be regulated in a photo-induced route. The laser-induced repulsion force at this interface is enough to compromise the Brownian diffusion of single molecules in a range of several hundred nanometers normal to the solid/liquid interface. This observation is fundamentally and practically interesting because moderate laser intensity is enough to initiate this repulsion effect. Therefore, it might display extensive applications in the development of photo-modulation technique with high throughput capability.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide