Study On Detection Of Glucose By Peptide Stabilized Noble Metal Nanoparticles

Compared with natural peroxidases,noble metal nanoparticles can not only effectively simulate the properties of peroxidases,but also effectively solve their defects such as inactivation and storage difficulties.Although the small-sized noble metal nanoparticles have higher catalytic activity,they have the disadvantage of easy agglomeration and the lower stability will significantly reduce their catalytic performance.In this paper,zwitterionic peptides?daptomycin and EK-5 peptide?were used to prepare stable noble metal nanoparticles,their peroxidase-like properties,glucose detection performance and plasma glucose concentration were studied.The specific research contents are as follows:?1?Daptomycin was used as the templates to successfully prepare 10 nm gold nanoparticles,2 nm palladium nanoparticles and 8 nm platinum nanoparticles with good dispersion;EK-5 molecule was used as a template to successfully prepare 8 nm platinum nanoparticles with good dispersion.These nanoparticles were not only stable in buffer,but also in fibrinogen solution.?2?Both daptomycin and EK-5 stabilized noble metal nanoparticles had excellent peroxidase-like catalytic activity,they effectively catalyzed the oxidation reaction of3,3',5,5'-tetramethylbenzidine?TMB?by H₂O₂.In addition,the effects of temperature and pH on the catalytic activities of prepared noble metal nanoparticles were studied.Steady-state kinetic studies indicated that the catalytic kinetics of daptomycin-Au nanoparticles,daptomycin-Pd nanoparticles,daptomycin-Pt nanoparticles and EK-5stabilized Pt nanoparticles followed typical Michaelis-Menten equation.Among them,the K_m of daptomycin-Au nanoparticles for the substrate TMB was 0.2 mM,indicating that it had the highest affinity towards TMB;The V_m of daptomycin-Pt nanoparticles towards substrate H₂O₂ was 310.56×10^-8 M s^-1,indicating that it had the highest catalytic rate towards substrate H₂O₂.?3?Based on the peroxidase properties of daptomycin-Pd nanoparticles,daptomycin-Pt nanoparticles and EK-5 stabilized Pt nanoparticles,the colorimetric detection methods for glucose were established.The linear range of glucose detection method using daptomycin-Pd nanoparticles was 0.02-1 mM and the detection limit was5.6;the linear range of glucose detection method using daptomycin-Pt nanoparticles was 0.005-1 mM,and the detection limit was as low as 0.8,which was the lowest detection limit in this article;the linear range of glucose detection method using EK-5stabilized Pt nanoparticles was 0.01-1.4 mM and the detection limit was 2.3,the linear range of this method was the largest in this article.The above methods were applied to the detection and analysis of blood glucose in plasma;the results were consistent with the standard method.