The Study Of Meso-fluidic Microbeads Biochip System And Its Application In Genotyping

A novel meso-fluidic biochip system has been established in this study. This is a highly integrated system which has got kinds of priority such as highly sensitive, multiplex analysis, low cost and low pollution, and it only takes 30 min for one test. In this platform, beads of 250μm diameter are lined in a determined sequence in a micro channel, and then connected with silicone tube. Each bead is chemically modified with APTMS and then reacted with PDITC to isothiocyanate-modified beads (NCS-Beads). Afterwards, amino-terminal oligonucleotides probes were covalently attached onto the surface of NCS-Beads. The hybridization is easily completed by introducing Cy5-labled target samples (50μl) into the micro channel with a peristaltic pump. The target ss-DNA will be captured by the corresponding probes, after the scanning of fluorescence signal, compared to the position of the addressable micro-beads, we can get the result of geno-analysis. Experiments which is to optimize the time and concentration to immobilizate probes onto the surface of micro-beads have been carried out, and the results show that with 3μM probe concentration,12hr for immobilization gives a good result. This mesofluidic analysis system can detect the lowest target concentration is 1×10-11M. The system was applied in the genotyping of 8 mutant sites ofβ-Thalassemia and HLA-DQA. The results indicate that gene mutations and the genotype can be determined with high sensitivity and specificity. With further development of the the new concept we developed a new meso-fluidic biochip device, which has integrated constructions of meso-fluidic chip, control of the fluid in channel, automated-sampling, DNA hybridization reactions, washing and in situ fluorescence detection modelers. It has got a good prospect in biological fundamental research, clinical diagnosis, environmental monitor and food safety.