Polymer grafted mesoporous SBA-15 material synthesized via metal-free ATRP as pH-sensitive drug carrier for quercetin

Abstract

PH-sensitive amphiphilic poly(2-(diethylamino)ethyl methacrylate) (PDEAEMA) were grafted from mesoporous silica molecular sieve SBA-15 surface via metal-free atom transfer radical polymerization (metal-free ATRP). The amino group was introduced onto SBA-15 surface by silane coupling agent KH-550, followed by the ATRP initiator SBA-15-Br was obtained after bromoisobutyryl bromide (BIBB) immobilized onto SBA-15 surface. The PDEAEMA grafted SBA-15 (SBA-15-g-PDEAEMA) inorganic–organic hybrid materials were prepared by surface initiated metal-free ATRP using SBA-15-Br as initiator, 10-phenylphenothiazine (PTH) as photocatalyst, 2-(diethylamino)ethyl methacrylate (DEAEMA) as the monomer. Then, the anticancer drug quercetin was loaded onto SBA-15-g-PDEAEMA hybrid material (SBA-15-g-PDEAEMA-Qu) and the controlled release of quercetin was investigated. The analytical results indicated that the ATRP initiator has been successfully anchored onto the SBA-15 surface and the ordered structure of the mesoporous material has been maintained. The kinetic plots and the curve of the relationship between Mn and monomer conversion illustrates that the polymerization process has the characteristics of “living”/controllable radical polymerization. The TGA results showed that the graft rate of organics in SBA-15 channel is 24.7%. In vitro cytotoxicity evaluation and cell uptake assay results indicated that the cytotoxicity of SBA-15-g-PDEAEMA to the L929 cells had completely disappeared on the 3rd day, SBA-15-g-PDEAEMA has good biocompatibility and can be endocytosed by L929 cells. The drug release rate of SBA-15-g-PDEAEMA hybrid material loaded with quercetin (SBA-15-g-PDEAEMA-Qu) at pH = 5.5 is significantly higher than that at pH = 7.4, the SBA-15-g-PDEAEMA hybrid material can be used as carrier for controlled drug release and has potential application prospects in clinical practice.