Quantum‐Dot‐Labeled DNA Probes for Fluorescence In Situ Hybridization (FISH) in the Microorganism Escherichia coli

Abstract

Semiconductor quantum dots (QDs) as a kind of nonisotopic biological labeling material have many unique fluorescent properties relative to conventional organic dyes and fluorescent proteins, such as composition‐ and size‐dependent absorption and emission, a broad absorption spectrum, photostability, and single‐dot sensitivity. These properties make them a promising stable and sensitive label, which can be used for long‐term fluorescent tracking and subcellular location of genes and proteins. Here, a simple approach for the construction of QD‐labeled DNA probes was developed by attaching thiol‐ssDNA to QDs via a metal–thiol bond. The as‐prepared QD‐labeled DNA probes had high dispersivity, bioactivity, and specificity for hybridization. Based on such a kind of probe with a sequence complementary to multiple clone sites in plasmid pUC18, fluorescence in situ hybridization of the tiny bacterium Escherichia coli has been realized for the first time.