Synergetic Peroxidase-Mimic Catalytic Activity of Noble-Metal-Decorated Lithium Niobate Nanozymes for Potential Biological Applications

In this paper, we report a simple, facile, and efficient method to obtain LiNbO3/Au and LiNbO3/Pt nanoparticles composed of LiNbO3 NPs (LN NPs) (30 nm) and ultrasmall nanoparticles (<5 nm, seeds) of Au and Pt, respectively. The synthesis of the nanocomposites followed a simple layer-by-layer method introducing branched poly(ethyleneimine) (BPEI) as a linker. By varying the volume of metal seeds dispersion added to the LN coated with BPEI, the loading of metal on the surface of the LN is controlled. The morphology of the as-prepared composite is characterized by transmission electron microscopy (TEM), energy-dispersive spectrometry (EDS), and dynamic light scattering (DLS). Its applicability as peroxidase mimics is investigated and compared to the separated counterparts (LN NPs, LN@BPEI, AuSeeds, PtSeeds, and a simple mixture of LN NPs and metal seeds). The synthesized nanoparticles follow the Michaelis-Menten kinetic model with enhanced catalytic activity compared to the metal seeds alone. This intrinsic peroxidase activity makes them promising candidates for applications in biomedicine. In particular, the low Michaelis constant Km and high maximum velocity Vmax for the H2O2 are of great interest for H2O2 sensing and generation of reactive oxygen species for antimicrobial applications.