Liquid Biochip Coding By Impedance Of Microspheres And Its Application On Laboratory Medicine

Objective:To research and develop different impedance encoded microspheres for liquid biochip and detection device to provide the experimental basis and scientific proof, we have conducted research and discussion of different impedance coding microsphere quantitative detection technology and its application in laboratory medicine.Methods and results:1) To put forward the theoretical values and microspheres impedance theory formula and the microsphere impedance resistivity is inversely proportional to their sizes.2) Preparing three kinds of different particle diameters of carboxyl polystyrene microspheres and impedance characterization analysis, it was found, microspheres impedance stability can maintain in more than1year, with different particle size and concentration of particles in solution settling velocity and particle size and concentration is proportional to the microspheres.3) With the assistance of blood counting instrument to distinguish between the different particle sizes of impedance encoded microspheres and reference to Kurt theory of electrical impedance, we have originated detecting and distinguishing technology and device. Three different particle sizes microspheres was detected for microporous ends voltage variation signal, as impedance coding microsphere size bigger, microporous both ends of the voltage variation signal is stronger, for different size impedance microsphere coding technology to provide a practical and scientific experimental basis.4) The human alpha fetal protein (AFP) monoclonal antibody, human insulin (INS) monoclonal antibodies and human tumor necrosis factor alpha (TNFa) monoclonal antibodies were marked at2,5and10micron diameter impedance coding microsphere surface. By surface fluorescence intensity quantitative detection function in flow cytometry, we set different diameter impedance coding microsphere quantitative detection of the antigen and enzyme linked immunosorbent assay (ELISA) technology methodology for performance comparison. Impedance coding microsphere quantitative detection technique is better than that of ELISA technology in the detection of repetitiveness, accuracy, lowest limit, linear range and etc..5) Using quantum dot labeled streptavidin (B-QD) and biotinylated antibody (AAb-A) microsphere surface Quantum Dots Fluorescent Display System (AAb-AB-QD) to replace the traditional FITC labeled antibodies microsphere surface fluorescence intensity display system (AAb-FITC), it was found detecting with the same concentration of insulin microsphere surface quantum dot fluorescence intensity (MFI) was significantly higher than that of the microsphere surface FITC average fluorescence intensity, coefficient of variation is greater than FITC fluorescent display system.6)Using three different sizes impedance encoding immune diagnose microballoons quantitative detection technology, respectively, for quantitative detection of clinically diagnosed serum AFP in patients with hepatocellular carcinoma, serum insulin in patients with type2diabetes mellitus and serum TNFa level in patients with MODS, the results show that were significantly higher than those in the normal control group. Conclusion:Different diameter impedance microsphere coding technology has feasibility and scientificity. It outperforms the ELISA technology in methodology of detecting antigen in quantity, and can be practice preliminary application in clinical diagnosis. Different diameter impedance encoded microspheres liquid biological chip and detection device has the feasibility and scientificity, worthy of further study.