Lidocaine-TiO₂ Composite Coating for Chest Tubes: Modulating Sustained Drug Release, Antiadhesive Performance, and Antibacterial Properties.

Abstract

Chest tubes used in cardiothoracic surgery must meet critical clinical requirements, including effective analgesia, inhibition of protein adhesion, and prevention of infection. In this study, a dual-layered coating was developed, comprising an inner lidocaine (LDC) layer for localized analgesia and an outer TiO₂ layer that serves three functions: modulating the sustained-release kinetics of LDC, providing antiadhesive properties, and offering antibacterial activity. The LDC-TiO₂ quantum dot coating was prepared via dip-coating, which involved an initial reaction between the LDC intermediate layer and hydroxyl groups on the pretreated polyurethane surface, followed by reaction with the outer TiO₂. Scanning electron microscopy revealed a uniform dispersion of quantum dot-sized TiO₂ within the LDC layer, forming a 4 μm-thick composite coating. In vitro drug release assays showed sustained LDC release over 24 h, maintaining a concentration of 0.14-0.48 mg mL^-1 from the LDC-TiO₂ coating, meeting the requirement of clinically effective analgesic concentration. Furthermore, the catheter with LDC-TiO₂ coating exhibited a substantial reduction in protein adhesion to 0.071 mg cm^-2, compared with 0.343 mg cm^-2 for the single LDC coating, indicating effective antiadhesive efficacy. In addition, the antibacterial performance, evaluated via bacterial plate counting, demonstrated significant inhibition against Escherichia coli (43.72%) and Staphylococcus aureus (70.14%). The enhancements in sustained-release behavior, antiadhesive properties, and antibacterial activity are attributed to the hydrophilic and antimicrobial properties of the outer TiO₂ coating. The proposed LDC-TiO₂ coating is promising for achieving sustained drug release and reducing catheter-related infections.