Multiple hybridizations using quantum dot-DNA probes for rapid analysis of microbial community on reverse osmosis membrane Original Research Article

Special emphasis has recently laid on the biofouling on RO membrane surface for desalination process to provide a better insight into the microbial community composing of biofilms. However, it appears that conventional RFLP tool, which is used to quantify and identify bacterial population, is inefficient for this study purpose, as it requires intensive time and labor. To meet the requirement of on-site application and a shorter analysis time, detection of microbial community by multiple hybridization using fluorescent Quantum dot (QD)–DNA probes are suggested since the excitation of multi-QD probes is possible with a single excitation light source. In our study, streptavidin-coated QDs 525, 585 and 655 were used to detect three different target bacteria in a single experiment, and each QD streptavidin was conjugated to specific oligonucleotides DNA of each bacteria. The hybridization between mixed target DNA of Mycobacterium sp., Rhodobacter sp. and Bacillus sp. and each complementary QD–DNA probe occurred in a separation-dependent solution phase. In comparison with the conventional RFLP method, it appeared that the application of QD–DNA probe was quick and promising, as it provides the information of mixed bacteria in a single test.