Preparation and evaluation of controllable drug delivery system: a pH and temperature responsive nanosphere based on chitosan copolymer/mesoporous silica

A pH/temperature dual response drug release system (MSNs@CMCS-g-PNIPAM) was prepared in this study. Around the core of mesoporous silica nanoparticles (MSNs), the copolymer of carboxymethyl chitosan (CMCS) and poly (N-isopropylacrylamide) (PNIPAM) was shelled. The CMCS was used as a pH-sensitive functional component in copolymers, and the PNIPAM was used as a temperature-sensitive functional component. The copolymer modification on the surface of mesoporous silicon was achieved through hydrogen bonding. Several characterization techniques were utilized to characterize the structure of the carrier, which include FTIR, TGA, XRD, XPS, N-2 adsorption/desorption, and SEM. The adsorption results showed that the carrier had the best adsorption capacity for doxorubicin hydrochloride (DOX) at pH 7, with drug loading rate and encapsulation rate of 7.43% and 82.99%, respectively. In vitro release experiments demonstrated that the cumulative drug release rate was 4.63 times higher under dual stimulation of pH 5.5 and 45 degrees C than pH 7.4 and 37 celcius, proving the carrier has pH and temperature responsiveness. In addition, the erythrocyte hemolysis test and CCK8 test proved the biocompatibility of MSNs@CMCS-g-PNIPAM. The results indicate that MSNs@CMCS-g-PNIPAM might be a strong candidate for drug carriers.