Preparation and Drug Release Property of Poly(p-dioxanone) Antibacterial Fiber Coated with Chitosan/Polydopamine

The adhesion of coating layer, retention of mechanical properties and release control of antibacterial agents have always been the goals and challenges in the preparation of medical sutures. This work constructed a rough and uniform chitosan/polydopamine (CS/PDA) composite coating on biodegradable poly (p-dioxanone) (PPDO) monofilament. A rough structure is conducive to drug adhesion. Subsequently, the antibiotics levofloxacin (Levo) and triclosan (TCS) were introduced into the composite coating by impregnation and in-situ loading methods. Compared with immersion method, in-situ drug loading could effectively control the release rate of drugs. The release kinetics of TCS conformed more closely to the Korsmeyer Peppas model (R2 ≥ 0.94), and was dominated by Fickian diffusion. The antibacterial rates of fibers loaded with Levo and TCS against Escherichia coli were 97.5 and 93.4%, respectively, while the antibacterial rates against Staphylococcus aureus were 94.3 and 99.9%, respectively. In vitro cytotoxicity tests showed that the composite fiber possessed excellent biocompatibility. Additionally, the tensile strength of composite fiber still maintained 13.66 N after 4 weeks in vitro degradation. This ensures sufficient mechanical stability during its service life. This study provides a feasible strategy for developing surgical sutures that combine mechanical stability, controlled drug release, and efficient antibacterial properties.