Multi-wavelength fluorescence detection of submicromolar concentrations using a filter-free fluorescence sensor

Abstract In this paper, we report on the development of a filter-free fluorescence sensor for the detection of multiple fluorescence wavelengths from a solution of fluorescent dyes with submicromolar concentrations. The filter-free fluorescence sensor has a photo-gate structure, and the intensities of excitation light and fluorescence can be calculated from the photocurrents for the different gate voltages. This sensor makes it possible to measure various wavelengths without the need for optical filters or mirrors. The separation ability of excitation light and fluorescence in the developed sensor was more than 1000:1 for an LED light source. Fluorescence measurements were carried out for fluorescein isothiocyanate isomer (FITC) and sulforhodamine 101 acid chloride (Texas Red) dyes. Based on our calculations, the excitation light and fluorescence from submicromolar concentrations of FITC, Texas Red, and a mixed solution were successfully separated and simultaneously detected.