Fabrication and Characteristics of Quercetin-Loaded Mn-Doped SiO2 Nanospheres Coated with Carboxymethyl Chitosan

Abstract

The biodegradability of inorganic nanocarriers is one of the most critical issues in their further clinical translations. In this work, a manganese-doped approach was developed to endow inorganic mesoporous silica (SiO2) nanospheres with pH-sensitive biodegradation. Manganese-doped mesoporous silica nanospheres (MMS) were prepared by in-situ doping method, with a particle diameter of 160–175 nm and pore diameter of 3–5[Formula: see text]nm by characterization of N2 adsorption method, powder X-ray diffraction, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectrum, field emission scanning electron microscope and transmission electron microscope techniques. Quercetin was used as the model drug to load, and MMS loaded with quercetin (MMS–QUE) was surface-modified using a carboxymethyl chitosan (MMS–QUE–CMCS) to prevent quercetin leakage. Based on the dissolution characteristics of manganese ions and the swelling behavior of carboxymethyl chitosan, the MMS–QUE–CMCS could be degraded in response to acid. The MMS–QUE–CMCS delivery system exhibited a good pH-responsive release. The cytotoxicity test showed that the MMS–QUE–CMCS had a significant biocompatibility and an enhanced cytotoxicity, thus revealing that the MMS–QUE–CMCS was a promising delivery system.