Visual and real-time imaging focusing for highly sensitive laser-induced fluorescence detection for nanocapillaries at yoctomoles level
A visual and real-time imaging alignment and highly sensitive laser-induced fluorescence detection system was developed for the detection of analytes in nanocapillaries. A cylindrical lens is adopted for the shaping of a laser beam to increase the spatial resolution. The limit of detection with a radius of 440 nm capillary is 6.76 yoctomoles(or four molecules) for fluorescein, and 84.5 yoctomoles for FAM-labeled Hsa-miR-17 (or 51 molecules). The designed system exhibits high sensitivity and stability for femtoliters samples and is considered suitable for single-cell analyses.