Thermo and pH-responsive nanocarriers based on mesocellular silica foam and poly(N-vinylcaprolactam-co-methacrylic acid): Synthesis, characterization, and in vitro cytotoxicity assay

Abstract

Smart hybrid nanocarriers were prepared by grafting poly(N-vinylcaprolactam-co-methacrylic acid) (poly(NVCL-co-MAA)) onto mesocellular silica foams (MCF silica) to evaluate them as controlled delivery systems of doxorubicin (DOX). The development of these nanocarriers began with the synthesis of MCF silica with interconnected porous structures and an average pore diameter of 27 nm. Then, free radical polymerization was used to graft the smart copolymer, and some parameters such as comonomer concentration and reaction time were studied. The DOX was loaded by immersion in an aqueous drug solution, while the in vitro release was investigated at different pHs (7.4, 5.8) and temperatures (25, 37 °C). In addition, the cytotoxicity of nanocarriers was investigated in vitro using the direct contact method with human breast cancer cells (SKBR3). In general, hybrid nanocarriers with copolymer graft percentages ranging from 30 to 60 % were obtained. On the other hand, at higher grafting of poly(NVCL-co-MAA) onto MCF silica, higher drug loading (up to 6.41 × 10−2 mg DOX/mg HN) was observed. Furthermore, in vitro DOX release results suggested that the nanocarriers released up to 52 % at 37 °C and a pH of 5.8. Finally, the in vitro cytotoxicity assay revealed that the DOX-loaded hybrid nanocarriers were cytotoxic to SKBR3 cells, indicating a controlled administration of DOX from the nanocarriers compared to free DOX. These results suggest that nanocarriers could have great potential for use as controlled delivery systems of anticancer drugs.