A facile fluorescence lateral flow biosensor for glutathione detection based on quantum dots-MnO2 nanocomposites

A newly designed quantum dots and manganese dioxide nanosheets nanocomposite-based fluorescence lateral flow biosensor was developed for rapid detection of glutathione (GSH). In this biosensing system, nanocomposites of biotinylated quantum dots (Biotin-QDs) and MnO2 nanosheets were first fixed on the conjugation pad of the test strip. The addition of GSH could trigger the decomposition of nanocomposites by digesting MnO2 nanosheets and consequently release Biotin-QDs. Under the capillary effect, the free Biotin-QDs would continue to move forward and be captured by streptavidin (SA) on the test line due to the specific binding between biotin and SA. Thereafter, an obvious fluorescent enhancement can be observed on the test line with a portable strip reader as well as naked eyes under irradiation by a 365 nm handheld ultraviolet lamps, which was used successfully for the quantitative detection of GSH with a short assay time of 20 min. Furthermore, this biosensor was utilized for GSH detection in diluted HeLa cells extracts (1%) samples with satisfactory results, which can meet low concentration detection for GSH with a good linear relationship in the range from 0.05 to 1.2 mM. Holding the advantages such as simple, convenient, rapid and cost effective, this developed fluorescence lateral flow biosensor has a great potential to be used for GSH detection in point of care diagnosis.