Temperature-sensitive copolymer-coated fluorescent mesoporous silica nanoparticles as a reactive oxygen species activated drug delivery system.

In this study, a temperature and ROS-responsive drug delivery system ROSP@MSN based on mesoporous silica nanoparticles has been designed and synthesized by taking advantage of 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl acrylate modified polymers (ROSP) as "nano-valve", which can respond selectively to cancer exclusive microenvironment and implement targeted drug release. Due to the superior temperature-sensitive properties of ROSP, ROSP@MSN could achieve cargo loading in cold water, and subsequently close the pore by raising temperature to obtain ROSP@MSN@DOX. Upon the stimulus of ROS, ROSP@MSN@DOX shows good release performance at physiological conditions. The cytotoxicity study demonstrates that the cell viability is about 80% after Hela cells are treated with ROSP@MSN at a concentration of 100 μg/mL for 24 h, exhibiting the good biocompatibility of ROSP@MSN. Furthermore, after treated with ROSP@MSN@DOX at a concentration of 100 μg/mL for 24 h, the viability of Hela cells is reduced to 40.5%; Control experiments demonstrate that, when Hela cells are pretreated with active oxygen scavenger, cell viability is about 65.3% due to the significant decrease of intracellular reactive oxygen species. Therefore, the therapeutic nanocarrier with effective encapsulation and release capacity in particular situation is a great candidate for the new drug delivery platform for targeted cancer therapy.