Flow Cytometry

....We have developed a new microfluidic device utilizing multi-wavelength detection for high-throughput Capillary Electrophoresis (CE) analysis. In general, different fluorescent dyes are only excited by light sources having appropriate wavelengths. When excited by an appropriate light source, a dye emits specific fluorescence signals of a longer wavelength. The experiment designs and fabricates plastic micro-CE chips capable of performing multiple-wavelength fluorescence detection by means of multi-mode optic fiber pairs embedded downstream of the separation channel.

....For detection purposes, the fluorescence signals are enhanced by positioning micro-focusing-lens structures at the outlets of the excitation fibers and the inlets of the detection fibers, respectively. The proposed device is capable of detecting multiple samples labeled with different kinds of fluorescent dyes in the same channel in a single run. The experimental results demonstrate that various proteins, including BSA (Bovine Serum Albumin) and β casein, can be successfully separated and detected by coupling two light sources of different wavelengths to the two excitation optic fibers.

....Furthermore, the proposed device also provides the ability to measure the speed of sample travel in the microchannel. The developed multi-wavelength micro-CE chip has significant potential for the analysis of DNA and protein samples.