Preparation And Catalytic Detection Performance Of Platinum Nanoparticles

Natural peroxidase can carry out a variety of catalytic reactions and is widely used in the fields of biological detection,environment and disease treatment.Due to its complex extraction process,high price,poor stability and tolerance,the development of nanoparticles with like-peroxidase activity has become the focus of attention.Among them,platinum nanoparticles have relatively high catalytic activity,but they are easy to agglomerate in the process of preparation and catalysis.In order to solve the above problems,we used lily polysaccharide and zwitterionic sulfhydryl betaine sulfonate as templates to prepare platinum nanoparticles with high stability,and studied their preparation conditions,enzyme catalytic activity,catalytic kinetics,stability,catalytic mechanism and cell toxicity and the application of biological molecular detection.The main contents and conclusions are as follows:（1）Platinum nanoclusters（Pt_n-LP NCs,n=10,20 and 40）and palladium nanoparticles（Pd_n-LP NPs,n=6.6,13.2 and 19.8）were successfully prepared from water-soluble and reductive lily polysaccharides,respectively.Pt_n-LP NCs and Pd_n-LP NPs were monodisperse and stable.Pt nanoclusters have smaller particle sizes than Pd nanoparticles,and Pt₁₀-LP NCs have higher activity than Pd_6.6-LP NPs in catalyzing H₂O₂ oxidation of3,3’,5,5’-tetramethylbenzidine（TMB）to produce blue product（ox TMB）.The kinetic equation of Pt₁₀-LP NCs followed Michaelis Menten equation.Compared with HRP,Pt₁₀-LP NCs had stronger binding ability and higher catalytic efficiency for TMB and H₂O₂.The peroxidase activity of Pt₁₀-LP NCs was due to its ability to catalyze the decomposition of hydrogen peroxide into hydroxyl radicals.（2）Platinum nanoparticles（SB-SH/Pt NPs）supported with sulfhydryl betaine sulfonate were successfully prepared by using water-soluble amphoteric sulfhydryl betaine sulfonate as template.Platinum nanoparticles were cubic and monodisperse.SB-SH/Pt NPs remained stable in both aqueous and protein containing solutions.SB-SH/Pt NPs catalyzed the oxidation of TMB by H₂O₂ to produce blue ox TMB,which had the activity of peroxidase-like activity and had higher catalytic efficiency than Pt₁₀-LP NCs.The catalytic kinetic equation of SB-SH/Pt NPs followed Michaelis Menten equation.The peroxidase activity of SB-SH/Pt NPs was attributed to the production of superoxide anion（O₂^-）and singlet oxygen（¹O₂）.（3）Based on the peroxidase-like activity of platinum nanoparticles,the contents of biomolecules were detected by colorimetry.Firstly,the standard curves for colorimetric detection of glucose and glutathione were established based on Pt₁₀-LP NCs.The linear range of glucose detection was 2.5-1000μM,and the detection limit was 1.89μM;the linear range of glutathione detection was 4-140μM,and the detection limit was 0.37μM.This method can detect the content of glutathione in human serum and has high recoveries.In addition,SB-SH/Pt NPs were used to establish the standard curve for colorimetric determination of glutathione.The linear range of detection was 10-120μM,and the detection limit was 0.244μM.This method detected the content of dopamine in real samples and had high recoveries.