Ultra-Sensitive Analysis of Microcystin LR Using Microchip Based Detection System

摘要

For the detection of cyanobacterial toxin,an Enzyme-linked immunosorbent assay(ELISA)was integrated into a PDMS microchip.The conjugates of microcystin-LR(MCLR)and keyhole limpet hemocyanin(KLH)were adsorbed on the surface of polystyrene beads and these MCLR-KLH polystyrene beads were introduced into a microchamber.MCLR on the surface of polystyrene beads reacted with horseradish peroxides(HRP)conjugated anti-MCLR monoclonal antibody(mAb)which had a competitive reaction with MCLR in water sample.After the enzyme substrate 3,3,5,5-tetramethyl benzidine(TMB)was injected into the chamber and catalyzed by HRP,the color change was detected with a liquid-cord waveguide.This integration shortened the conventional ELISA analysis time from several hours to about 30 min with only 4.2 |uL MCLR sample consuming which was useful for the environmental analysis.More over,troublesome operations required for ELISA could be replaced by simple operations.The microchip based detection system showed a good sensitivity of 0.05 ng/L and maintained good reliability through its quantitative range with low coefficients of variation(2.5-10.5%).