Preparation And Smart Drug Delivery Property Of Gold Nanorods/Mesoporous Silica/Aliphatic Poly (Urethaneamine) Hybrid Nanoparticles

Intelligent drug delivery system?DDS?has a great potential in controllable drug release field owing to the controlled drug release behavior under external stumuli.In this work,we got thermal-/pH-/NIR-responsive gold nanorods?AuNRs?/mesoporous silica?SiO₂?/Aliphatic poly?urethane-amine??PUA?nanoparticles via in situ grafting functional PUA on the surface of Au/SiO₂ nanoparticles in supercritical CO₂.This novel DDS was fabricated to couple the photothermal property of AuNRs and the ther-mal-/pH-responsive properties of polymer into a single nanovehicle.The present thesis provided a new fabrication route to get inorganic/polymer hybrid nanovehicles with excellent intelligent properties.This paper is divided into the following three parts.First,Au/SiO₂/PUA nanoparticles were fabricated on the basis of Au/SiO₂ core by in situ polymerization under supercritical CO₂ environment.The characterization results of TEM and UV illustrated the core-shell structure of Au/SiO₂/PUA nanoparti-cles.Under high-temperature and high-pressure reaction condition,hybrid nanoparti-cles kept good morphology and expected optical property.The successful in situ graft-ing of PUA on the surface of Au/SiO₂ nanoparticles had also been demonstrated by FTIR and XPS.The TG curves illustrated the grafted-PUA content in hybrid nanopar-ticles was around 17.81%in weight.Au/SiO₂/PUA nanoparticles had a BET surface area of 337.49 m²g^-1 and a BJH pore diameter of 1.03 nm,indicating the relatively high drug loading capacity.Then,in vitro photothermal conversion and responsive drug release behavior of Au/SiO₂/PUA nanoparticles were investigated.Au/SiO₂/PUA nanoparticles exhibited an excellent photothermal conversion property and local temperature could rapidly in-crease to over 60^oC under 4 W/cm² near-infrared?NIR?irradiation.So,a short time exposure to NIR irradiation could distinctly introduce a significant hydrophilic/hydro-phobic changes of PUA,and the thermal-responsive polymeric cap enabled the DOX release.Besides,Au/SiO₂/PUA nanoparticles could exhibite distinguished pH?ther-mal and NIR responsive release behaviors.Thermal-responsive PUA coupled with photothermal conversion of AuNRs acted as the switcher to control the DOX release under the remote NIR light in a significant reversible way by simply turning on or turning off the NIR laser.At last,the specific DOX release kinetics of Au/SiO₂/PUA nanoparticles in different experimental conditions were analyzed to explain the interrelationship between the structures of hybrid nanoparticles and drug release behavior.And the biocompatibility of drug carrier was investigated.