Magnetic stimuli-responsive chitosan-based drug delivery biocomposite for multiple triggered release

Stimuli-responsive biomaterials offer a unique advantage over traditional local drug delivery systems in that the drug elution rate can be controllably increased to combat developing symptomology or maintain high local elution levels for disease treatment. In this study, superparamagnetic Fe₃O₄ nanoparticles and the antibiotic vancomycin were loaded into chitosan microbeads cross-linked with varying lengths of polyethylene glycol dimethacrylate. Beads were characterized using degradation, biocompatibility, and elution studies with successive magnetic stimulations at multiple field strengths and frequencies. Thirty-minute magnetic stimulation induced a temporary increase in daily elution rate of up to 45% that was dependent on field strength, field frequency and cross-linker length. Beads degraded by up to 70% after 3 days in accelerated lysozyme degradation tests, but continued to elute antibiotic for up to 8 days. No cytotoxic effects were observed in vitro compared to controls. These promising preliminary results indicate clinical potential for use in stimuli-controlled drug delivery.