Synthesis of chitosan-based micelles for pH responsive drug release and antibacterial application

The over- and inefficient release of antibiotics from common delivery systems causes the development of drug-resistant bacteria. In the present work, methoxy poly(ethylene glycol)-poly(ε-caprolactone)-chitosan/montmorillonite (MPC/MMT) hybrid multilayer films were constructed for bacterial infections and pH-dependent release of the hydrophobic drug triclosan (TCA). The thickness of the (MPC-T/MMT)10 multilayer films was 384.4 ± 26.5 nm, and the TCA loading dosage was 2.4 μg/cm2. Staphylococcus aureus, Escherichia coli and Staphylococcus epidermidis were used in the antibacterial tests. pH responsive TCA release from the prepared multilayer films was examined by measuring the bactericidal activity of the films after immersion in PBS (pH 7.4) or MES (pH 5.5) and zone of inhibition on nutrient agar. In vitro bacterial shake-flask, zone of inhibition and live/dead staining results demonstrated the high sterilization efficiency of the films. Furthermore, cell biocompatibility measurements toward L929 fibroblasts and human lens epithelial cells showed no adverse effects of the multilayer film.