On-Site Identification of Ancient Silk Residues Based on CdSe/ZnS Fluorescent Immunochromatographic Strip Assay

Obtaining information about proteins is crucial for exploring the origin and distribution of ancient silk. However, complex burial environments often cause degradation of silk. During archaeological excavations, these silk residues were usually in the form of fibers, fabric fragments or coatings, and in some cases even degrade into peptides that are difficult to find with the naked eye. In this work, a fluorescent immunochromatographic strip assay based on CdSe/ZnS quantum dots, which have high fluorescence quantum yield, good stability, and wide range of excitation wavelengths, was developed for on-site detection of silk residues. The results showed that the strip assay possessed good specificity and recognized silk fibroin within 15 min with a limit of detection (LOD) of 42.66 ng/mL. The strip assay was also successfully utilized for the analysis of ancient silk residues and assisted in obtaining information on residual proteins. In addition, the strip assay is portable, easy to use, and suitable for batch screening and testing. Therefore, this study provides a new strategy for rapid identification of silk residues.