Recyclable detection of gefitinib in clinical sample mediated by multifunctional Ag-anchored g-C3N4/MoS2 composite substrate

Surface-enhanced Raman scattering (SERS) technology enables to satisfy the increasing demand of clinical drug monitoring due to the superiority of fingerprint recognition, real-time response, and nondestructive collection. Here, a novel graphitic carbon nitride (g-C3N4)/ molybdenum disulfide (MoS2)/Ag composite substrate with a 3D surface structure was successfully developed for the recyclable detection of gefitinib in serum. Attributed to the uniform and dense "hotspots" on the shrubby active surfaces in conjunction with the potential synergistic chemical enhancement of g-C3N4/MoS2 heterosystem, a remarkable SERS sensitivity with an attractive enhancement factor value of 3.3 x 107 was demonstrated. Meanwhile, a type-II heterojunction between g-C3N4 and MoS2 enabled more efficient diffusion of photogenerated e--h+ pairs assisted by the localized surface plasmon resonance of Ag NPs, which contributed to the reliable recyclable detection of gefitinib. The ultra-low limit of detection at 10-5 mg/mL and high recycling rates of gefitinib beyond 90% in serum were successfully realized. The results demonstrated the as-prepared SERS substrate has tremendous potential to be untilized for in-situ drug diagnostics.