Novel Design for Multi-Channel DNA Sequencing System

Today most commercial DNA sequencing systems´ signal detection was based on CCD or PMT. The CCD based system needs cooled CCD, whose cost is high and the sensitivity is relatively low. The PMT based system using mechanical scanning to realize multi-channel detection, whose stability is relatively low and the working noise is high. In this paper, a novel multi-channel DNA sequencing system was presented, which was based on single PMT confocal fluorescence detection and optical scanning adopting an f-theta lens. Capillary electrophoresis experiments were executed in the system for DNA marker pBR322/Hae III. The system´s limit of detection was evaluated to be 1.1841times10^-11 mol/L (dsDNA with Thiazole Orange). Its working noise is much lower compared with that based on mechanical scanning one, and the stability and detecting sensitivity is high. The system is expected to be applied to both capillary array and microchip electrophoresis detection based on laser-induced fluorescence.