Tracing Invisible Silk: Immunological Methods for Archaeological Residue Analysis

Tracing Invisible Silk: Immunological Methods for Archaeological Residue Analysis tackles a fundamental challenge: how to detect silk after it has degraded beyond visibility—mixed with soil, mineralized on iron, or burned in sacrificial ash. Traditional morphological and spectroscopic methods fail when fiber structures disappear. This monograph presents a complete immunological workflow to solve this problem. Starting from the discovery of silk residues in the Sanxingdui sacrificial pits, the author systematically develops species-specific monoclonal antibodies that distinguish mulberry silk from tussah, castor, wool, cotton, and flax. Two complementary enrichment tools are then constructed: immunomagnetic beads for micro‑trace samples (e.g., soil adhered to artifact surfaces) and immunoaffinity columns for large‑volume ash layers (e.g., the 20‑cm‑thick deposits at Sanxingdui). Using these tools, two rapid detection methods are established—a double‑antibody sandwich ELISA for quantitative lab analysis and a fluorescence‑based method for on‑site screening within 1.5 hours. The entire system is validated on authentic archaeological samples, including the ash layer at Sanxingdui (where the silkworm fibroin signature protein P05790 was identified), mineralized fabric on an iron knife from Maoling Mausoleum, and fabric impressions from acidic burials at the Suijalong site and Changxing Han Dynasty tomb. This work demonstrates that even when macroscopic fabric has completely vanished, protein‑level information can survive for millennia and be reliably identified. It provides archaeologists and heritage conservators with a practical technical toolkit, extending silk detection from “visible fabric” to “molecular‑level residues” and opening new avenues for exploring the origin and spread of silk along the ancient Silk Road.