Development of pH-Sensitive Microbeads Incorporated with Amine-functionalized Magnetic Nanoparticles for Enhanced Antibacterial Activity

Antibiotic-resistant bacteria have rapidly emerged in recent years as a result of irrational use of antibiotics. The development of drug carriers that can enhance antibacterial activity of antibiotics can potentially overcome antibiotic resistance and hence has practical significance. This study addresses this need by integrating amine-functionalized magnetic nanoparticles (AMNPs) into hydrogel microbeads composed of sodium alginate (SA) and xanthan gum (XG) for delivery of levofloxacin (LVX). Characterization of the microbeads confirmed successful AMNP–polymer interactions and demonstrated a porous structure inside the microbeads. The microbeads demonstrated pH-sensitive drug release behavior, enabling prolonged drug release. The drug encapsulation efficiency in the hydrogel microbeads was higher after AMNP incorporation, indicating the potential roles played by the porous network and by AMNP-LVX interactions during drug loading. The microbeads adhered to first-order, Higuchi, and Korsmeyer-Peppas kinetic models, suggesting that a combination of diffusion and polymer relaxation mechanisms is involved in drug release. Along with the fact that the AMNP-incorporated microbeads exhibited enhanced antibacterial activity against various bacterial strains, our microbeads warrant further development and optimization as drug carriers for antibacterial applications.