Efficient 2D MOFs nanozyme combining with magnetic SERS substrate for ultrasensitive detection of Hg²

Biomimetic inorganic nanoenzyme is a kind of nanomaterial with long-term stability, easy preparation and low cost, which could instead of natural biological enzyme. Metal-organic framework (MOFs) as effectively nanoenzyme was attracted more attention for the adjustability and large specific surface area. This design is based on the catalase-like catalytic activity of 2D metal-organic frameworks (MOFs) and the high sensitivity of surface enhanced Raman spectroscopy (SERS) biosensors to construct a novel SERS biosensor capable of efficiently detecting mercury (Hg²⁺). In this study, 2D MOFs nanozyme was instead of 3D structure with more effecient catalytic site, which can catalyze o-Phenylenediamine (OPD) to OPDox with the assistance of H₂O₂. Besides, a magnetic composite nanomaterial Fe₃O₄@Ag@OPD was prepared as a signal carrier. In the presence of Hg²⁺, T-Hg²⁺-T base pairs were used to connect the two materials to realize Raman signal change. Based on this principle, the SERS sensor can realize the sensitive detection of Hg²⁺, the detection range is 1.0 × 10^-12 ∼ 1.0 × 10^-2 mol‧L^-1, and the detection limit is 1.36 × 10^-13 mol‧L^-1. This method greatly improves the reliability of SERS sensor for detecting the target, and provides a new idea for detecting metal ions in the environment.