Near-infrared Light-regulated Plasmon-Nanozyme With Enhanced Catalytic Activity

Nanozymes are a class of mimic enzymes that have both the unique physical and chemical properties of nanomaterials and catalytic functions.Compared with natural enzymes or other artificial enzymes,nanozymes have the advantages of high catalytic activity,low cost,stability,and large-scale production,which makes them widely used in medical,chemical,food,agricultural,and environmental fields.The activity of nanozymes can be regulated by a variety of methods.Among them,the optical regulation has the advantages of long range,high time and spatial resolution,which have attracted widespread attention.Compared to ultraviolet and visible light,near-infrared light can reach the maximum depth in biological tissues,so-called biological tissue optical windows.In addition,near-infrared light can avoid the cytotoxicity of ultraviolet light.Therefore,the regulation of nanozymes by near-infrared light is of great value in the field of biomedicine.This subject is aimed at the design,preparation,and biomedical application of near-infrared light-tuning nanozymes.Composite nanoparticles with platinum loaded on both ends of gold nanorods are prepared by different methods.The photothermal effect and hot electron effect caused by plasmons contribute to the enhancement of the catalytic activity of the nanozyme,and the cell-level application of the nanozyme is further investigated,showing the potential value and significance of tumor treatmentThe main contents and results of this article are listed as follows:First,the seed-induced growth method was used to control platinum growth on both ends of the gold nanorods to obtain platinum-gold nanorod composite nanoparticles.Under the optimization of the synthesis conditions,we obtained the platinum-gold nanorod nanozymes with the central absorption wavelength of around 808 nm,which would be suitable for the study of nanozymes under irradiation of near infrared lightNext,the nanozymes catalytic activity of platinum-gold nanorods was studied.We investigated the catalytic activity under near-infrared light irradiation and the corresponding enhancement mechanisms.It was found that under near-infrared light irradiation,the catalytic efficiency of the platinum-gold nanorod nanozymes could be increased by 2.5 times,which could be ascribed to the plasmon-induced photothermal effect and hot electron effect.Then,the nanozyme catalytic activity in the cellular level was also evaluated.Under the irradiation of near-infrared light,the platinum-gold nanorods would lead to a significant tumor cell apoptosis because of the synergistical effect between the photocatalytic and photothermal effects.These results suggest that the platinum-gold nanorod nanozymes possess the promise in cancer therapy.Finally,we prepared the platinum-gold nanorod nanozymes upon the regulation of nucleic acid.In order to further optimize the catalytic performance and improve the bio-affinity,we used nucleic acids to regulate nanocrystals growth,and obtained the nucleic acid-passivated platinum nanoparticle-gold nanorod.This bimetallic nanoparticle could be used as the new nanozyme for the future biomedical applications.