Controllable Construction Of Near-infrared Synergistically Responsive Nanoparticles Based On Gold Nanorods And Reduced Graphene Oxide

Intelligent responsive drug delivery carriers could control the drug release according to the various environmental conditions.In this thesis,near-infrared?NIR?-responsive core-shell gold nanorods/mesoporous silica/reduced graphene oxide?Au/SiO₂/rGO?nanoparticles with synergistically enhanced photothermal stability and transition effect had been prepared via electrostatic interaction and layer by layer?LbL?technology.Then,graphene oxide?GO?was modified by 4-Arm-?polyethylene glycol?-aminor?4-Arm-PEG-NH₂?,the nanoparticles?Au/SiO₂/GO-PEG?with good stability in physiological buffer were obtained.The present thesis provided a new approach for the tumor combined treatment based on photothermal therapy and chemotherapy.This paper is divided into the following parts:First,in order to enhance NIR photothermal stability and photothermal transition effect of gold nanorods/mesoporous silica?Au/SiO₂?drug carrier,rGO with high thermal conductivity and high specific surface area was combined with Au/SiO₂ to prepare Au/SiO₂/rGO drug carrier with two kinds of thickness SiO₂ shell via electrostatic interaction.The structure of Au/SiO₂/rGO nanocarriers was demonstrated by UV-Vis-NIR,AFM,Raman,TEM and Zeta potential.Then,the photothermal stability of Au/SiO₂/rGO and Au/SiO₂ nanoparticles with two different thicknesses SiO₂ shell was studied.The photothermal conversion performance of rGO in Au/SiO₂/rGO nanoparticles was also explored.The results indicated that the nanocarrier exhibited enhanced NIR photothermal stability and synergistic enhancement of photothermal conversion efficiency.Drug release properties and drug release kinetics of Au/SiO₂/rGO and Au/SiO₂ were studied.The drug release rate of Au/SiO₂/rGO was faster than that of Au/SiO₂,indicating that synergistically enhanced photothermal effect between rGO and Au NRs endowed Au/SiO₂/rGO nanoparticles with excellent photothermal transition efficiency.At last,in order to further improve the stability of nanocarriers in physiological buffer and make full use of high specific surface area of graphene,GO was modified by 4-Arm-PEG-NH₂.Au/SiO₂/GO-PEG nanoparticles were then prepared via electrostatic interaction.The results demonstrated that 4-Arm-PEG-NH₂ could improve the stability of Au/SiO₂/GO-PEG nanocarriers in physiological buffer,compared with the Au/SiO₂/rGO nanoparticles,the drug loading efficiency increased from 26.7%to 85.9%,and the drug release efficiency increased from 12.1%to 39.7%,the NIR responsive drug delivery property of nanoparticles was polished up.