Fabrication Of Copper-Tannic Acid And Ferri-Tannin Nanosheets And Their Application In Biosensing And Antibacterial Properties

Natural enzymes with high catalytic capability and substrate specificity have attracted significant research interest in biomedical area due to their intrinsic biocatalytic property involved in all biological process.Nanozyme is a type of nanomaterial that possesses intrinsic enzyme-like activity.Nanozymes have attract great research attention due to their advantages over natural enzymes,such as stability against condition variations,easy storage,low cost in preparation and tunable catalytic activity.Given these properties,nanomaterial-based artificial enzymes have attracted increasing attention and interest from biosensing,photocatalysis,energy,biomedicine,environmental,and biological fields in recent years.In this paper,a series of sensing methods are established for biomolecules assay and antibacterial applications based on the metal tannic acid two-dimensional nanosheets possesses peroxidase mimetic activity and oxidase mimetic activity,including the following three aspects:1.We have developed a novel colorimetric biosensor for the detection of H2O2 and glucose based on copper-tannin nanosheet possesses peroxidase mimetic activity.Copper/tannin nanosheet(CuTA)possesses peroxidase activity were prepared from copper ions and tannic acid,which could catalyze the oxidation of 3,3,5,5tetramethylbenzidine(TMB)with the help of H2O2.Based on its peroxidase mimetic performance,a colorimetric sensing platform for the detection of H2O2 and glucose was designed.The linear range for H2O2 is from 1 to 2000 μM and the limit of detection(LOD)is 1 μM.Based on the observation,a colorimetric sensing method for glucose is further developed with the assistance of glucose oxidase(GOD).The linear range for glucose is from 5 to 500 μM and the limit of detection(LOD)is 5 μM.The strategy showed good selectivity for glucose detection.These properties will allow for wider applications in the environmental,biological,and analytical fields.2.Herein,a facile fluorescence assay was developed for the accurate detection of ascorbic acid and α-glucosidase(α-Glu)with copper-tannin nanosheet as a highly efficient peroxidase-mimicking nanozyme.The copper-tannin nanosheet could catalyze hydrogen peroxide to generate hydroxyl radicals(·OH).The terephthalic acid could be oxidized by hydroxyl radicals to form a highly fluorescent 2-hydroxy terephthalic acid.The peroxidase-like activity is inhibited in the presence of ascorbic acid(AA).Based on this property,a fluorescence assay was developed for the determination of AA by exploiting the peroxidase-like activity of copper-tannin nanosheet in the range of 1-1000 μM with a detection limit as low as 0.32 μM.Subsequently,ascorbic acid was produced from 2-O-α-d-glucopyranosyl-l-ascorbic acid(AAG)which was selectively hydrolyzed by α-glucosidase.This fluorescent method showed a good linear relationship with the activity of α-glucosidase from 0.1 to 5 U/mL and low detection limit of 0.031 U/mL.This fluorescence strategy was successfully applied to the determination of α-glucosidase in serum samples with satisfactory results.With high selectivity and sensitivity for α-glucosidase assay demonstrated a remarkable applicability in human serum samples.This method has some good prospects for potencial applications in the field of clinical diagnostics,biological or pharmaceutical analysis.3.Bacterial infections pose a large public health concern due to the rapid emergence of antibiotic resistance.Artificially synthesized nanozymes which can increase the level of reactive oxygen species(ROS)in the bacterial system have become research hotspots.Herein,we describe the design and fabrication ferri-tannin nanosheet(FeTA)with peroxidase activity and oxidase activity.The antimicrobial mechanisms are explained as the production of abundant ·OH radicals derived from the peroxidase-like activity and and oxidase activity of FeTA nanosheet.Additionally,this nanozyme also exhibited highly effective antibacterial activity on Escherichia coli(E.coli)and Staphylococcus aureus(S.aure).This work provided a promising strategy for the design and development of nanozymes for future biomedical applications.This work provides a potential platform for future synergistic antibacterial application.