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 (Hg 2+ ). 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 H 2 O 2 . Besides, a magnetic composite nanomaterial Fe 3 O 4 @Ag@OPD was prepared as a signal carrier. In the presence of Hg 2+ , T-Hg 2+ -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 Hg 2+ , 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.