Size‐Dependent Optical Absorption of Layered MoS₂ and DNA Oligonucleotides Induced Dispersion Behavior for Label‐Free Detection of Single‐Nucleotide Polymorphism

Size‐dependent optical absorption of semiconductive (2H) layered molybdenum disulfide (MoS 2 ), exhibiting great discrimination abilities to single‐ and double‐stranded DNA (ssDNA) and (dsDNA), is studied. In the presence of high concentration of salt, layered MoS 2 trends to aggregate rapidly, leading to the increases of sizes in both vertical and lateral dimensions of the nanosheets, which results from the interplay between van der Waals attraction and electrical double‐layer repulsion. Meanwhile, the aggregation behavior of layered MoS 2 is remarkably inhibited by the synergistic effects of DNA oligonucleotides. ssDNA can adsorb on the surface of layered MoS 2 , resulting in a great dispersion, even in the presence of high concentration of salt, while the dispersion behavior is weakened when…