Evanescent scattering imaging of single molecules

A system comprising:

• a flow cell comprising an optically transparent substrate, wherein the flow cell is configured to facilitate flow of a sample solution over a first surface of the substrate and target molecules and the first surface is configured to bind to target molecules if present in the sample;
• a light source configured to irradiate the first surface with an incident light having an incident angle selected to achieve total internal reflection of the incident light, wherein a wavelength of the incident light is in a range of 10 nm and 350 μm, and the optically transparent substrate has a refractive index at the wavelength of the incident light exceeding that of the sample solution and an incident angle is selected to achieve total internal reflection of the light;
• at least one camera;
• and
• an optical system comprising one or more lenses, apertures, spatial filters, beam blocks, mirrors, beam splitters, or combinations thereof, arranged along an optical path between the first surface and the at least one camera, wherein the optical system is configured to capture interference between evanescent light scattered from the first surface and evanescent light scattered from the target molecules if present on the first surface, the evanescent light from the first surface arising from nanoscale surface roughness, while avoiding collection of specularly reflected light from the first surface to form a series of images on the camera.