Portable Multi-color Fluorescent Detection for Point-of-care

This work describes a portable multi-color fluorescence detection system based on a CMOS image sensor and polarization signal isolation. Taking advantage of the wavelength independent nature of the cross-polarization scheme, microparticles with different emission can be excited and detected simultaneously. By changing excitation light polarization the detection can be switched between bright and dark field. The high spatial resolution (~3μm) and contrast lead to the accuracy of ~98% in particle counting and ~97% in size measurement. The spectral resolution provides additional means to distinguish fluorescently labeled particles even of the same size.