Abtract:This study elucidates the frequency response and optical detection characteristics of series photodetector frequency circuit system matched with polydimethylsiloxance (PDMS) for detection of fluorescence dye concentration. While the same fluorescence intensity irradiated on the photodetector, the series photodetector frequency circuit system with higher responsivity of photodetector had higher frequency sensitivity. In accordance with Cy5 fluorescence dye concentrations and frequency responses, the detection limit of fluorescence dye concentration 2 pmol/l can be measured by 100 MHz sensor system matched with PDMS. The results also showed that the frequency shift of the sensor system matched with photodetector PT was linearly related to the logarithm of fluorescence dye concentration from 2 to 20 μmol/l. Moreover, the frequency sensor system had a potential application in the detection of deoxyribonucleic acid (DNA) hybridization with PDMS microfluidic chip.