Synthesis of mesoporous silica nanoparticle-encapsulated alginate microparticles for sustained release and targeting therapy.

This study reports the synthesis of mesoporous silica nanoparticle-encapsulated alginate microparticles (MSN@Alg) for sustained release and targeting therapy. The MSN@Alg was synthesized by air dynamical atomization, and the effects of several critical factors including concentration of alginate solution, flow rate of alginate solution, flow rate of air, the distance between nozzle and calcium bath, and stirring rate of calcium on the particle size of the synthesized MSN@Alg were investigated. For studying the sustained release properties of the MSN@Alg, rhodamine 6G (R6G) was used as a model drug, and we compared the release properties of R6G/MSN and R6G/MSN@Alg using different concentrations of alginate, concentrations and volumes of phosphate-buffered saline (PBS) buffer solutions. The sustained release behavior of the R6G/MSN@Alg system can be prolonged to 20 days with an optimal condition of 1 mg R6G/MSN@Alg to 2 mL PBS (10 mM). To achieve targeting therapy, an anticancer drug, doxorubicin (Dox), was loaded into MSN@Alg, and a arginine, glycine, and aspartic acid (RGD)-based peptide was functionalized onto the surface of MSN@Alg for the purpose of specific targeting. The results showed that the intracellular drug delivery efficiency was greatly enhanced (i.e., 3.5-folds) for the Dox/MSN@Alg-RGD drug delivery system.