Au Nanoparticles on Two-Dimensional MoWS₂ as Highly Sensitive Surface-Enhanced Raman Spectroscopy Substrates for Adenine Detection

Adenineis a simple purine base and an integral part of DNA andRNA. The sensitive detection of adenine is not only fundamental forDNA identification and sequencing but also important for the diagnosisof many metabolism-related diseases. In this work, a composite structureprepared by reducing Au nanoparticles (AuNPs) on the surface of two-dimensional(2D) MoWS2 ternary alloys was used for the label-free andhighly sensitive detection of adenine based on the surface-enhancedRaman spectroscopy (SERS) technique. The AuNP/MoWS2 compositeas the SERS substrate can successfully detect rhodamine 6G moleculeswith a limit of detection (LOD) of 10(-11) M and adeninewith LODs of 10(-9) M in aqueous solution and 10(-8) M in simulated urine. The excellent Raman enhancementof AuNPs/MoWS2 originates from the synergistic effect ofelectromagnetic enhancement from AuNPs and chemical enhancement from2D MoWS2. Moreover, AuNPs/MoWS2 exhibit a goodlinear detection range for adenine from 10(-5) to10(-9) M, as well as excellent uniformity and reliablestability, highlighting the potential of using 2D hybrid SERS substratesfor applications in biological detection and clinical diagnosis.