Defect-rich Graphene Stabilized Pd-M Bimetallic Nanozymes: Preparation And Antibacterial Application

In recent years,the number of bacteria has gradually increased and the abuse of antibiotics has led to bacterial resistance,which seriously threatens human health and life.In order to solve this threat,it is urgent to find new antibacterial agents.Nanozymes have attracted much attention because of their unique properties of nanomaterials and catalytic functions that mimic natural enzymes.In this paper,the defection-rich nanodiamond/graphene stabilized Palladium-iron bimetallic nanozyme(PdFe/ND@G)was prepared through a simple and green deposition-precipitation method.The atomically dispersed palladium-iron bimetallic site effectively improved the oxidase-like catalytic activity and antibacterial performance of the nanozyme.PdFe/ND@G nanozyme can catalyze the decomposition of oxygen(O2)to generate hydroxyl radicals(·OH),thereby killing bacteria.Compared with single-metal Pd/ND@G and Fe/ND@G nanozyme,PdFe/ND@G nanozyme have stronger catalytic activity and antibacterial properties.In addition,in order to verify that atomically dispersed bimetallic sites are conducive to improving the catalytic performance of the nanozyme,we prepared the defected nanodiamond/graphene stabilized Palladiumcobalt bimetallic nanozyme(PdCo/ND@G)by the same method.The research contents are as follows:(1)Preparation and characterization of PdFe/ND@G nanozyme.Firstly,the nanozyme precursor was prepared by adding palladium nitrate(Pd(NO3)2)and iron nitrate(Fe(NO3)3)mixed solution with the defective nano-diamond/graphene(ND@G)as the carrier at 100 ?.Then PdFe/ND@G nanase was obtained by reducing the precursor in hydrogen(H2)atmosphere at 500 ?.Finally,XRD,XPS,Raman,ACHa ADF-STEM and XAFS were used to systematically characterize the nanomaterials.(2)Study on the oxidase-like catalytic activity and antibacterial activity of PdFe/ND@G nano-enzyme.The catalytic activity of of PdFe/ND@G nanozyme was investigated by 3,3',5,5'-tetramethylbenzidine(TMB)oxidation reaction.The results showed that PdFe/ND@G nanozyme had strong oxidase-like catalytic activity compared with Pd/ND@G and Fe/ND@G nanozyme.The catalytic mechanism of PdFe/ND@G nanozyme was investigated by ESR test.The results showed that PdFe/ND@G nanozyme can catalyze oxygen decomposition to produce hydroxyl radical.The antibacterial performance of nanozyme against Gram-positive bacteria Staphylococcus aureus and gram-negative bacteria Escherichia coli was investigated by colony counting.The results showed that the atomically dispersed PdFe/ND@G bimetallic nanozyme has significantly enhanced antibacterial activity compared with single metal Pd/ND@G and Fe/ND@G nanozymes,which has potential application value in the biomedical field.(3)Preparation,characterization and antibacterial properties of PdCo/ND@G bimetallic nanozyme.The PdCo/ND@G nanozymes were prepared by deposition-precipitation method and systematically characterized by Raman,TEM and XRD.The results showed that the PdCo/ND@G bimetallic nanozyme had better oxidase-like catalytic activity and antibacterial performance compared with Pd/ND@G and Co/ND@G nanozyme.This paper has laid a foundation for the construction of novel oxidase mimics and antibacterial materials with excellent catalytic performance.