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

Adenine is a simple purine base and an integral part of DNA and RNA. The sensitive detection of adenine is not only fundamental for DNA identification and sequencing but also important for the diagnosis of many metabolism-related diseases. In this work, a composite structure prepared by reducing Au nanoparticles (AuNPs) on the surface of two-dimensional (2D) MoWS2 ternary alloys was used for the label-free and highly sensitive detection of adenine based on the surface-enhanced Raman spectroscopy (SERS) technique. The AuNP/MoWS2 composite as the SERS substrate can successfully detect rhodamine 6G molecules with a limit of detection (LOD) of 10–11 M and adenine with LODs of 10–9 M in aqueous solution and 10–8 M in simulated urine. The excellent Raman enhancement of AuNPs/MoWS2 originates from the synergistic effect of electromagnetic enhancement from AuNPs and chemical enhancement from 2D MoWS2. Moreover, AuNPs/MoWS2 exhibit a good linear detection range for adenine from 10–5 to 10–9 M, as well as excellent uniformity and reliable stability, highlighting the potential of using 2D hybrid SERS substrates for applications in biological detection and clinical diagnosis.