Study On Ultra-small Size Noble Metal Nanozymes And Research On Their Detection Performance

Natural peroxidase had good catalytic activity and can be used to detect glucose,vitamin C,etc.,but it has the disadvantages of easy inactivation,difficult storage and high cost.Noble metal nanoparticles have similar peroxidase activity,which is beneficial to overcome the shortcomings of natural peroxidase.However,noble metal nanoparticles had the problems such as low stability and low biocompatibility due to the small size.In this paper,pericarpium citri reticulatae polysaccharides and bitter gourd polysaccharides were used as reducing agents and stabilizers,ultra-small,highly stable and biocompatibile noble metal nanoparticles were prepared.The size,stability,biocompatibility,biomimetic enzyme properties and detection applications of the prepared polysaccharide-loaded noble metal nanoparticles were studied.The specific research contents and conclusions were listed as follows:1.The pericarpium citri reticulatae polysaccharides and bitter gourd polysaccharides were separately incubated with metal precursors to prepare stable and ultra-small palladium nanoparticles(2-3 nm)and platinum nanoclusters(0.8-1.3 nm)in solution,this was based on the good water solubility of natural polysaccharides and their own reducing properties.These particles had good biocompatibility at concentrations within 60 μg/mL.2.The prepared nanoparticles such as pericarpium citri reticulatae polysaccharides-Pt nanoclusters,pericarpium citri reticulatae polysaccharides-Pd nanoparticles,bitter gourd polysaccharides-Pt nanoclusters,and bitter gourd polysaccharides-Pd nanoparticles significantly accelerated the reaction of hydrogen peroxide with 3,3’,5,5’-tetramethylbenzidine(TMB)to produce a blue product,they had peroxidase-like activity and good TMB affinity.Their catalytic kinetics followed Michaelis-Menten equation.The peroxidase-like activity of these nanoparticles was from their ability to catalyze hydrogen peroxide to generate hydroxyl radicals.3.The prepared polysaccharide stabilized noble metal nanozymes were used to detect bio-related molecules.Pericarpium citri reticulatae polysaccharides-Pt nanoclusters were used to establish a glucose detection method,the linear range was 1.43-143 μM,the detection limit was as low as 0.38 μM,and it was successfully applied to the detection of glucose in human fluids.Pericarpium citri reticulatae polysaccharides-Pd nanoparticles were used to establish a method for detecting glutathione,the linear range was 2-300 μM and the detection limit was 1.65 μM,this method was successfully used to detect glutathione in serum.With the help of bitter gourd polysaccharides-Pt nanoclusters,an ascorbic acid detection method was established with linear range of 2-100 μM and detection limit of 0.95 μM,the method was successfully applied to determine the ascorbic acid content in medical vitamin C tablets.A method for detecting hydrogen peroxide with a linear range of 20-320 μM and a detection limit of 2.04 μM was established by using bitter gourd polysaccharidesPd nanoparticles.