Controlled Release and Antibacterial Properties of Quercetin-Loaded Silica Hybrids for Drug Delivery

Natural products from plants are valuable alternatives to synthetic drugs for treating cancers and bacterial infections. However, their low solubility and absorption pose challenges, necessitating a biocompatible system for controlled release at the target site. Hybrid materials, such as silica (SiO2) encapsulating quercetin (Qu), offer a solution by protecting the organic compound and maintaining its anticancer and antibacterial properties. Two synthesis methods for quercetin-encapsulated silica were explored: one with an acid catalyst (SiO2-HNO3+Qu5%) and one without a catalyst (SiO2+Qu5%), aiming for an eco-friendly approach. The encapsulation efficiency of the silica matrix was analyzed, and release studies were carried out using UV–visible spectroscopy under physiological (pH = 7.4) and cancer (pH = 5.0) conditions. The release of quercetin was found to be pH-dependent, with the SiO2+Qu5% system demonstrating superior release capacity. However, the system synthesized with the acid catalyst exhibited better antibacterial activity, likely due to the release of nitrate ions. The study highlights the potential of these hybrid materials in drug delivery applications, balancing efficient quercetin release, and enhanced antibacterial effects.