We present the development and implementation of a spatially and spectrally resolved multipoint fluorescence correlation spectroscopy (FCS) system utilizing multiple end-capped optical fibers and an inexpensive laser source. Specially prepared end-capped optical fibers placed in an image plane were used to both collect fluorescence signals from the sample and to deliver signals to the detectors. The placement of independently selected optical fibers on the image plane was done by monitoring the end-capped fiber tips at the focus using a CCD, and fluorescence from specific positions of a sample were collected by an end-capped fiber, which could accurately represent light intensities or spectral data without incurring any disturbance. A fast multipoint spectroscopy system with a time resolution of ∼1.5 ms was then implemented using a prism and an electron multiplying charge coupled device with a pixel binning for the region of interest. The accuracy of our proposed system was subsequently confirmed by experimental results, based on an FCS analysis of microspheres in distilled water. We expect that the proposed multipoint site-specific fluorescence measurement system can be used as an inexpensive fluorescence measurement tool to study many intracellular and molecular dynamics in cell biology.

Multi point fluorescence measurement system using basic image shifting method and commercial multi mode fiber is presented in this paper. Using a singlet lens, the original fluorescence image of a sample is shifted to another plane which can be monitored using ccd, and at the first image plane independent two fiber tips in an xyz stage deliver each fluorescent signal at a specific sample position to a fluorescence correlation spectroscopy (FCS) with an electron multiplying charge coupled device (EMCCD). The FCS is composed with an EMCCD, which can detect single molecule level fluorescence light. Applying region of interest (ROI) and pixel binning, a time resolution of up to 2 ms can be achieved, which is sufficient to resolve the diffusion of fluorescence micro-sphere in solution. The advantages of implementing EMCCD cameras in wide-field ultra low light imaging, as well as in site-specific multi-point fluorescence measurement system, can consequently also be exploited for spatially and spectrally resolved FCS. Experimental results about FCS with spectrum informations demonstrate the advantage of the simplicity and flexibility of our system. We expect that this multi point measurement system also can be applied to other study of bio molecular dynamics.