Defect Engineering of VN Nanowires Enables Dual-Mode SERS-Colorimetric Quantification of Glutathione in Serum

Abstract

The concentration of glutathione (GSH) in human blood is closely associated with various diseases, making rapid and accurate quantification of serum GSH levels crucial for health monitoring. In this study, we developed a dual-mode biosensor based on phosphorus-doped vanadium nitride@carbon nanowire (P-VN@C) derived from vanadium-based metal-organic frameworks (V-MOF), which integrates surface-enhanced Raman scattering (SERS) activity and catalase-mimicking catalytic functionality for quantitative detection of GSH in human serum. Experimental results demonstrate that V-MOF nanowires as precursors effectively retain their nanostructure through a high-temperature pyrolysis strategy. Phosphorus doping synergistically enhances both SERS performance (12-fold improvement compared to undoped VN) and enzymatic activity by introducing lattice defects and modulating the electronic structure of VN. In clinical serum analysis, the dual-mode sensor demonstrated consistent GSH quantification results between SERS and colorimetric detection modes (0.5 mM vs. 0.6 mM), with both values aligning within established clinical reference ranges. Density functional theory (DFT) calculations revealed that the SERS enhancement mechanism of P-VN@C stems from its superior charge transfer capability (0.4653 e/unit), representing an 8.4-fold increase over the undoped system (0.0554 e/unit). This work provides a novel material design strategy for developing high-performance, non-precious-metal-based sensors in clinical diagnostics.