Abstract

Surface plasmon resonance (SPR) sensor has been widely used in detection of biomolecular interaction due to its advantages of label-free and high sensitivity. The ligand-modified sensor surface specifically captures the analyte which results in a small increase of the refractive index (RI) that can be measured from the change in the optical response, such as intensity and wavelength. However, in real application of ultralow concentration, the distribution of caperaturing biomolecules on the sensing surface is usually nonuniform. The corresponding signals are averaged by whole detection area that hinder the improvement of limit of detection (LOD). The digital detection method provides an alternative approach for low-concentration detection[1]. By dividing the detection space into many small volumes, isolated signals in each volumes are counted.

© 2017 Japan Society of Applied Physics, Optical Society of America