A "dual-sieve" flexible SERS substrate: Synergistic molecular and physical filtration for ultra-sensitive discrimination of three amanitin subtypes.

Amanitin (AMA), a highly toxic octapeptide from Amanita mushrooms, poses severe poisoning risks due to misidentification. Herein, we developed a flexible SERS substrate integrating MIL-101(Cr), gold nanobipyramids (AuBPs) and cellulose nanofibers (CNF) with a "dual-sieve" impurity-exclusion mechanism. This platform achieves ultra-sensitive (LOD: 10-8 mg/mL) and rapid discrimination of α-, β-, and γ-AMA subtypes, with robust anti-matrix interference performance. It enables efficient AMA subtyping, providing a portable, reliable strategy for emergency mushroom poisoning screening and food safety diagnostics.