Construction of a Molybdenum Disulfide-Based Colorimetric Sensor for Label-Free Infectious Disease Analysis Coupled with a Catalyzed Hairpin Assembly Reaction

The simple and accurate determination of pathogenic infectious diseases is very beneficial to public health prevention and control. For this purpose, we designed a colorimetric sensor for label-free avian influenza A (H7N9) virus gene sequence detection based on gold@platinum core-shell bimetallic-nanoparticle-decorated molybdenum disulfide (MoS2-Au@Pt) nanocomposites. MoS2-Au@Pt nanocomposites were used as nanoenzymes to catalyze 3,3',5,5'-tetramethylbenzidine (TMB) by hydrogen peroxide (H2O2) because of their intrinsic peroxidase-mimicking activity. Coupled with different affinities of MoS2-Au@Pt nanocomposites toward single-stranded (ss) and double-stranded (ds) DNA and the target-triggered catalyzed hairpin assembly (CHA) reaction, the proposed sensor can qualitatively and quantitatively determine H7N9 by the naked eye. Experimental results showed that this sensor can detect H7N9 in buffer and real samples because of its high sensitivity, selectivity, and repeatability.