Rapid Enrichment and Detection of Silk Residues from Tombs by Double-Antibody Sandwich ELISA Based on Immunomagnetic Beads

The extraction and identification of silk residues in tombs is of great significance for studying the distribution and spread of early silk. However, the complex organic matter in the tomb hinders the accurate identification of silk. In this study, a double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) based on immunomagnetic beads (IMBs) was developed for the rapid enrichment and detection of silk residues. The double-antibody sandwich ELISA method established by pairing the IMBs prepared by the silk fibroin monoclonal antibody SF-3 and the silk fibroin monoclonal-labeled antibody bio-SF-1 had the highest detection sensitivity, with a linear detection range of 10 to 104 ng mL–1 and a detection limit of 5.12 ng mL–1. This method was excellent in the extraction and analysis of silk residues from archaeological imprints and soil samples and successfully identified silk residues in samples at the final stage of silk degradation (physical invisible silk). The proteomics analysis results demonstrated the feasibility and practicability of this method.