摘要 :
A natural enzyme acts as a catalyst by converting substrates into products,which can speed up biological reactions.In spite of their efficiency,enzymes have been hampered by a long list of stumbling blocks,exceptionally high conco...
展开
A natural enzyme acts as a catalyst by converting substrates into products,which can speed up biological reactions.In spite of their efficiency,enzymes have been hampered by a long list of stumbling blocks,exceptionally high concoction and depuration fetch,and poor stability,reducing their industry applications.Artificial enzymes that perform similar functions to natural enzymes are becoming increasingly popular as a way to overcome these limitations.Among the alternatives to natural enzymes,nanomaterials with superior catalytic activities are becoming increasingly popular.Because of their intrinsic enzyme-like properties,they are more commonly known as"Nanozymes." Nanozymes have been explored and blossomed a great deal before their time,but little has been done to enhance their catalytic orderliness.This thesis proposes a method for strengthening and modulating gold nanozymes'' catalytic activity by controlling their nanostructure morphology and near-infrared light irradiation.
This thesis synthesized stable Zirconium MOF-[Zr(OnPr)4]by a one-pot method.Then[Zr(OnPr)4]@AuNPs nanozymes were synthesized by seed growth method using[Zr(OnPr)4]as a template.The morphology and spectral properties of the gold nanozyme were characterized.Likewise,the TPS''s photothermal properties and enzyme activities have been systematically investigated.Results show that[Zr(OnPr)4]@AuNPs are ellipsoidal and have an intense absorption spectrum in the near-infrared(820 nm).The number of gold seeds can be controlled to precisely place the absorption peak.In some range of concentrations of gold nanozyme and illumination times,the light-induced curves showed that the gold nanozyme had a good photothermal effect.The enzyme kinetics test determined the nanoscale enzyme''s peroxidase activity.We systematically characterized the peroxidase activity of the nanozyme using enzyme kinetics.The results showed that[Zr(OnPr)4]@AuNPs nanozyme had good peroxidase-like activity,and the Km and Vmax values were as follows:0.43 mM for TMB and 5.33 mM for H2O2.Nanozyme exhibited a peroxidase-like activity under near-infrared irradiation.NIR illumination was discussed for its effect on enzyme activity.The numbers of ROS were evidently increased.Lastly,using gold nanozyme,the photothermal result effectively inactivated gram-positive and gram-negative bacteria.By creating a near-infrared light-induced gold nanozyme,this research also provides a new way to regulate nanozyme activity.
In chapter 4 of this work,photothermal treatment as an effective and precise bacterial disinfection way that can reduce the occurrence of bacterial drug resistance was investigated.However,most conventional photothermal treatment strategies have the problem that the photothermal response range does not match the infection area.Herein,a metal-organic framework(MOF)nanocomposite responding to the oxidation state of the bacterial infection microenvironment was constructed for near-infrared(NIR)photothermal bacterial inactivation.This strategy used MOF as a nanocarrier to load tetramethylbenzidine(TMB)and horseradish peroxidase(HPR).The high oxidation state of the bacterial infection microenvironment can trigger the enzyme-catalyzed reaction of the nanocomposite,thereby generating oxidation products with NIR photothermal effect for bacterial disinfection.The synthesis and characterization of the nanocomposite,oxidation state(H2O2)response effect,photothermal properties,and antibacterial activities were systematically studied.This study provides a new idea for building a precision treatment system for bacterial infection.
收起
