MoS2-based composite nanozymes with superior peroxidase-like activity for ultrasensitive SERS detection of glucose

Surface-enhanced Raman scattering (SERS) is an ultrasensitive fingerprint spectroscopy technique. The combined application of SERS and nanozymes has shown excellent prospects in the field of biomedical diagnosis. In the present study, polyaniline@MoS2@Fe3O4@Au (PANI@MoS2@Fe3O4@Au) nanozymes were successfully prepared using hydrothermal reactions. PANI@MoS2@Fe3O4@Au nanozymes have not only dramatically enhanced the peroxidase-like activity but also significantly enhanced the SERS performance. We also studied the effect of different concentrations of HAuCl4·4H2O on the SERS activity of nanozymes and found that PANI@MoS2@Fe3O4@Au nanozymes prepared using 2 mg mL−1 HAuCl4·4H2O solution exhibited the best SERS performance. We used SERS to study the enzyme kinetics of the nanozymes, and the results showed that the nanozymes have a strong affinity for H2O2 and TMB. Finally, we combined PANI@MoS2@Fe3O4@Au nanozymes and glucose oxidase (GOx) to establish a SERS glucose biosensor, which has the advantages of ultrasensitivity, high-precision, and a wide linear response range. The linear response range of glucose is 10−11–10−3 M, and the detection limit is 10−12 M. More importantly, we have successfully determined the glucose content in human serum samples with satisfactory accuracy. This work provides an essential new strategy for designing composite nanozymes for biocatalysis and provides a new idea for constructing high-sensitivity SERS biosensors.