High-performance photoelectrochemical immunosensor for ultrasensitive detection and species identification of ancient leather artifacts

Ancient leather artifacts provide critical insights into prehistoric and historic clothing and leatherworking techniques. However, their accurate detection and species identification remain challenging due to material degradation and environmental contamination. In this study, a high-performance photoelectrochemical (PEC) immunosensor was developed based on MoS₂/NiCo₂O₄-Ag@CoFe₂O₄ nanocomposites for the highly sensitive and specific analysis of archaeological leather. The immunosensor leverages a MoS₂/NiCo₂O₄ heterostructure for optimized energy band alignment and incorporates plasmonic Ag@CoFe₂O₄ nanocomposites to facilitate electron transport, significantly enhancing photoelectric conversion efficiency. A sandwich-type signal amplification strategy was employed, achieving an ultra-low detection limit of 0.1034   pg/mL (S/N = 3) and a broad linear range of 10⁻³–10² ng/mL, representing a two-order-of-magnitude improvement in sensitivity over conventional ELISA. The sensor demonstrated exceptional specificity, successfully distinguishing collagen from non-collagenous proteins and differentiating bovine collagen from pig collagen. In addition, it exhibited high stability and reproducibility, with a relative standard deviation (RSD) of 2.97%. Practical applicability was confirmed through qualitative and quantitative analysis of leather samples from multiple archaeological sites in Xinjiang, China. These results establish the proposed immunosensor as a reliable and robust tool for ancient leather identification, with potential applications in the analysis of other protein-based archaeological materials.