Ligand‐Engineering MoS ₂ ‐Osmium Heterostructure as Highly Active and Specific Peroxidase‐Mimic Nanozyme for Interference‐Free and Multimode Biosensing

It is still a challenge to fabricate nanozymes with both of high catalytic activity and specificity. Herein, a ligand engineering method is developed to fabricate osmium (Os) nanocluster-Molybdenum disulfide (MoS₂) heterostructure with superior peroxidase-specific activity. It has been verified that polyvinylpyrrolidone (PVP) as ligands can confine amorphous Os nanoclusters growing on the MoS₂ nanosheet, mechanism studies indicated that PVP acts as appropriate size-limiting reagent and electronic transmission bridge between of Os and MoS₂ which can synergistically improve the peroxidase-specific activity. Moreover, the ligand engineering will not affect the peroxidase-mimic specificity of MoS₂-Os. Further, it is found that MoS₂-Os possessed superior photothermal conversion efficiency, therefore, MoS₂-Os can be used as colorimetric and photothermal dual-mode tags. MoS₂-Os combined lateral flow strip is established for breast cancer HER2⁺ exosomes colorimetric and photothermal detection with superior sensitivity and broader liner range, MoS₂-Os based interference-free salivary glucose biosensor is also established with a LOD of 0.1 µM, almost 100-fold sensitivity than that of Glucose Assay Kit. Therefore, this work developed a ligand-engineering strategy to regulate Os nanocluster on MoS₂ and improve the peroxidase-specific activity, the multifunctional MoS₂-Os nanozyme can be used for accurate and multimode biosensing in varies scenes.