Influence of particle size of mesoporous silica composite nanoparticles coated with pH/temperature responsive copolymer on ibuprofen release behaviors

The bimodal mesoporous silicas nanoparticles (BMMs) with small size of 20-50 nm and mesoporous silicas nanoparticles (MSNs) with large sizes from 80 nm to 280 nm were synthesized using sol-gel method. These functionalized mesoporous silicas composites with different sizes were acquired by environmental responsive (pH/temperature) copolymer coated onto the mesoporous silica hosts via the seed polymerization method. The structural features and textual parameters of resultant samples were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope, N-2 adsorption-desorption isotherms, thermogravimetric analyses, FT-IR, DLS, SAXS technologies, indicating that copolymer was successfully coated on the mesoporous silicas. Meanwhile, functionalized mesoporous silicas composites as drug carries were used to explore the pH/temperature responsive efficiency. These results showed that compared with the blank mesoporous silicas nanoparticles, mesoporous silicas composites realized a reduced initial burst release. In particular, the particle size of mesoporous silicas composites effects on the release behaviors were found that the smaller composite nanoparticles with short mesoporous channels exhibited highly pH/temperature response compared to the larger composite nanoparticles with long mesoporous channels. Meanwhile, their IBU-release kinetic profiles followed Korsmeyer-Peppas model. Moreover, the toxicity of mesoporous silicas composites was evaluated in vitro. It found that the particle size of mesoporous silicas composites was essential for its cytotoxicity.