High-load, sustained-release antibacterial composite particles based on modified vaterite coated with quaternary ammonium chitosan and aldehyde hyaluronic acid for controlled drug delivery systems.

Porous vaterite particles exhibit good biocompatibility, degradability, and favorable physical and chemical properties, making them promising candidates for drug carriers. However, challenges such as low loading capacity, burst release effect and limited antibacterial properties hinder their practical applications. Herein, submicron vaterite particles were synthesized at low temperature and modified by stearic acid, and the resulting modified vaterite particles (Vc) possess exceptional loading capacity towards a typical anticancer drug - doxorubicin. Quaternary ammonium chitosan (QCS) with antibacterial properties was synthesized by chemically modifying chitosan and was coated onto the surface of Vc/Dox through electrostatic adsorption. AgCO nanoparticles were uniformly deposited on the surface of Vc/Dox/QCS through the reaction between Ag and CO, while a small amount of Ag nanoparticles was generated through the reduction of adsorbed Ag, which was attributed to the reducing properties of -NH and aldehyde groups. Aldehyde functionalized hyaluronic acid was adsorbed on the outermost layer as a targeting polymer with the ability to induce cellular interaction. The composite (Vc/Dox/QCS/Ag/AHA) showed excellent sustained release and pH responsiveness, and the presence of QCS, Ag, and AgCO nanoparticles provided good antibacterial properties for the composite particles. In addition, cell experiments confirmed the almost no-cytotoxic properties and effective cellular interaction of the composite particles treated by low Ag concentration solutions. Compared with various micro-nanoparticles, this study ingeniously employed multifunctional polymers, Layer-by-Layer (LbL) technique, and modified inorganic nanoparticles to address the limitations of vaterite particles, paving the way for enhanced drug delivery applications and inspiring the development of multifunctional targeted drug capsules.