Preliminary in vitro Antibacterial Screening of Nanochitosan-functionalized PLA Monofilament Sutures for Potential Intraoral Wound-closure Applications

Abstract

Aims: The study aims to compare the antibacterial performance of nanochitosan-functionalised polylactic acid (PLA) monofilament suture formulations and to determine whether surface coating provides a more favourable preliminary profile than bulk blending for potential intraoral wound-closure applications. Study Design: Preliminary in vitro comparative formulation-screening study. Place and Duration of Study: Laboratory-based biomaterials screening conducted at Universitas Sumatera Utara and collaborating laboratories in Indonesia. Methodology: The experimental sample comprised six distinct formulation groups (n_formulations = 6): PLA dip-coated with commercial nanochitosan and sodium tripolyphosphate (TPP) (A1), PLA dip-coated with naturally derived nanochitosan and TPP (A2), an uncoated PLA control (A3), PLA blended with commercial nanochitosan (B1), PLA blended with naturally derived nanochitosan (B2), and a blended-branch PLA control (B3). Antibacterial activity against Staphylococcus aureus was the primary endpoint and was assessed by inhibition-zone diameter. Mucosal-cell viability and tensile properties were retained as supporting indicators. Results were reported descriptively as mean ± standard deviation; no inferential significance was claimed. Results: A1 produced the numerically largest inhibition zone (16.8 ± 1.2 mm), followed by A2 (14.2 ± 1.0 mm), B1 (10.5 ± 0.9 mm), and B2 (9.2 ± 0.8 mm); A3 and B3 produced no inhibition. All formulations remained above the 70% preliminary non-cytotoxicity threshold, with A1 showing 92.5 ± 3.1% viability. A1 retained tensile strength of 34.84 kgf/mm² and had the greatest elongation at break (22.20%) among the formulations. Conclusion: Within this preliminary formulation-level screening, surface-localised nanochitosan—particularly the commercial nanochitosan/TPP coating—showed the most favourable numerical balance of antibacterial activity, cytocompatibility, and mechanical adequacy. The findings identify A1 as a lead formulation for powered antibacterial testing, oral polymicrobial biofilm models, simulated saliva degradation, knot-security assessment, and in vivo wound-healing validation.