A novel SERS aptasensor based on Au-Mn-Cu nanozyme induced catalytic precipitation reactions combining with catalytic hairpin assembly strategy for sensitive detection of chloramphenicol

Chloramphenicol (CAP) is an antibiotic that has the potential to induce irreversible aplastic anemia. Therefore, developing sensitive detection methods for CAP has become crucial. In this study, an aptasensor for the detection of CAP was developed by integrating catalytic precipitation reactions using a gold (Au)-manganese (Mn)-copper (Cu) nanozyme with surface enhanced Raman spectroscopy (SERS). First, a trimetallic nanozyme composed of Au, Mn, and Cu was synthesized, exhibiting horseradish peroxidase-like activity. Subsequently, target CAP induced catalytic hairpin assembly (CHA) cycle can open a large number of hairpin H1, enabling the binding of nanozyme@H2 to the SERS substrate Fe₃O₄@SiO₂@Ag@4-chloro-1-naphthol (4-CN). The trimetallic nanozyme can catalyze the conversion of 4-CN into benzo-4-chloro-hexadienone (4-CD), which further initiates catalytic precipitation reactions (NCP), resulting in a decrease in the Raman signal of 4-CN. By this way, the aptasensor could achieve a sensitivity at 3.52 × 10^-13 mol/L, offering a novel strategy for the detection of CAP in food products.