Doxorubicin-loaded Mn-doped SiO2 nanospheres coated with carboxymethyl chitosan: fabrication, characterization, and in vitro evaluation

This work describes the preparation of manganese-doped mesoporous silica nanospheres via an in situ doping method. The results of scanning electron microscopy and N2 adsorption demonstrate that mesoporous silica possesses a spherical shape, a highly porous structure, a large specific surface area of 922.21 m2 g−1, and a pore volume of 0.257 cm3 g−1. The mesoporous silica nanocarrier is loaded with doxorubicin, and carboxymethyl chitosan encapsulation is performed to prevent doxorubicin leakage. The easy release characteristics of manganese under acidic conditions and the swelling properties of carboxymethyl chitosan endow the drug-loading system with an excellent pH/responsive release property. A cytotoxicity test shows that mesoporous silica nanospheres–doxorubicin–carboxymethyl chitosan had significant biocompatibility and enhanced cytotoxicity, thus revealing mesoporous silica nanospheres–doxorubicin–carboxymethyl chitosan as a promising delivery system.