Smart Drug Release Of Multi-response Hybrid Nanocarriers Based On SiO₂/Hydroxyapatite

With the increasing application of smart responsive drug carriers in the field of drug controlled release,multiple responsive drug carriers have attracted great attention.In this paper,hydroxyapatite(HAP)and functional polymer poly(N-isopropylacrylamide-co-acrylic acid)(P(NIPAM-co-AAc),PNA)were simultaneously introduced into gold nanorod/mesoporous silica(AuNRs/SiO2)nanocarriers,which produced biodegradable smart nanocarriers with near-infrared(NIR),pH and temperature responsiveness.Nanoscale drug carriers with multiple responsiveness and excellent biodegradability are rationally designed in this paper,which are highly attractive for the preparation of remote controllable drug delivery nanovehicles.This article is composed of the following three parts.At first,the surface of gold nanorods(AuNRs)was coated with HAP-doped SiO2 shell by soft templating method,and then PNA was coated on the surface of AuNRs/SiO2/HAP nanoparticles by emulsion polymerization to prepare hybrid AuNRs/SiO2/HAP@PNA core-shell nanoparticles.TEM and UV test results showed the successful preparation of AuNRs/SiO2/HAP@PNA core-shell nanoparticles and the morphology of the hybrid nanoparticles.FTIR and XPS results demonstrated that the PNA was successfully coated on the outer layer of’AuNRs/SiO2/HAP nanoparticles.The TG curve indicated that the PNA content of the AuNRs/SiO2/HAP@PNA nanoparticles was about 51.55%.Then,the biodegradability,photothermal conversion performance and smart drug release properties of AuNRs/SiO2/HAP@PNA nanoparticles were studied.The results showed that the nanoparticles could be completely degraded after immersing in acidic conditions for 24 h.At the same time,the pH-responsive drug release property could be obtained due to the degradation of nanoparticles.In addition,AuNRs/SiO2/HAP@PNA nanoparticles had excellent photothermal conversion capability for near-infrared light,and light can quickly raise the temperature of nanoparticles to above 50 °C,achieving NIR controlled drug release property.Afterimmersing AuNRs/SiO2/HAP@PNA in the media above its LCST,PNA on the surface of the hybrid nanoparticles would shrink and thermal-responsive drug release could be clearly observed.Therefore,AuNRs/SiO2/HAP@PNA nanoparticles displayed excellent degradability,photothermal conversion property and multiple responsive drug delivery properties(NIR,pH,temperature).Finally,in order to further simplify the combination of AuNRs/SiO2/HAP and PNA,the preparation of AuNRs/SiO2/HAP/PNA hybrid nanogels were investigated in this paper.The results demonstrated the prepared hybrid nanogels displayed stable and uniform dispersivity.The structure of hybrid nanogels was characterized by UV,TEM,Zeta potential,FTIR and TG.The smart drug release properties of the hybrid nanogels were preliminarily investigated.