Abstract:

Objective Hernia repair patches are crucial medical implants, but the popularly used polypropylene meshes (PPM) are found to encounter complications such as bacterial infection, postoperative adhesion, and foreign body reaction in clinical practice. This study aims to develop functionally coated patch with required antibacterial properties, hydrophilicity and biocompatibility, thereby providing a novel approach for the research of antibacterial and anti-adhesion composite patches.

Method A phytic acid / benzalkonium chloride (PA/BAC) coating was constructed on polypropylene patch by low-temperature plasma pre-treatment combined with one-step co-deposition, mildly fabricable within 4 h. The coating was characterized by field-emission scanning electron microscopy (FE-SEM), X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and water contact angle (WCA) analysis. The in vitro antibacterial efficacy of the coated patch against E. coli and S. aureus was evaluated using the agar diffusion method and colony-forming unit (CFU) counting method.

Results Comprehensive characterizations and in vitro experiments confirmed that phytic acid/benzalkonium chloride (PA/BAC)-coated polypropylene patches were successfully prepared with satisfactory multifunctional properties. FE-SEM observations revealed BAC concentration-dependent coating deposition. The PA/BAC (0.08%) group showed sparse large-sized deposits, the 0.1% group exhibited smaller and denser particles, and the 0.15% group formed a continuous dense full-coverage coating, attributing to enhanced electrostatic interactions between PA and BAC. FT-IR, XRD, and XPS verified successful PA/BAC deposition on polypropylene patches. Water contact angle (WCA) measurements indicated the original PP patch had a WCA of 110.5°, while PA/BAC-coated patches achieved rapid liquid wetting within 1.61-4.41 s, reflecting significantly improved hydrophilicity. Consistently, the bovine serum albumin (BSA) adsorption capacity of coated patches( (39.4±3.04)-(44.5±2.72) mg/g) was remarkably lower than that of the original PP patch( (67.2±3.87 ) mg/g), demonstrating good hydrophilicity and biocompatibility that supports anti-tissue adhesion potential. The compliance test results of the coated patch confirmed that the patch retained its compliance, with its intrinsic flexibility effectively preserved. In vitro antibacterial tests showed PA-coated patches had no obvious inhibition zones, whereas PA/BAC coatings exhibited BAC concentration-dependent activity, where inhibition zone diameters were 14.6-22.5 mm against E. coli and 21-40 mm against S. aureus, with antibacterial rates of 99.99%-100% for both strains. The results indicated satisfactory antibacterial activity of all PA/BAC coatings against E. coli and S. aureus, with the antibacterial rate increasing with rising BAC concentration. The outstanding antibacterial performance constitutes a key innovation of this study. Cytotoxicity assays revealed that the low BAC concentration (0.05%, 0.08%) groups maintained 76%-82% cell viability, with cells adhering well and retaining normal morphology, indicating acceptable coating biocompatibility.

Conclusion In order to address bacterial infection and postoperative adhesion of polypropylene hernia meshes in clinical use, this study proposes a surface functionalization strategy with PA and BAC. A PA/BAC coating was constructed on PP patches via low-temperature plasma pretreatment combined with one-step co-deposition, gently fabricated in 4 h. This mild, simple process enables PP mesh functionalization, relying on PA's surface affinity and electrostatic interactions between PA and BAC. Static water contact angle tests showed full droplet wetting on coated patches, indicating significantly enhanced hydrophilicity. Protein adsorption assays revealed a marked reduction vs. original PP patch, supporting anti-adhesion capacity. In vitro antibacterial tests demonstrated excellent efficacy against E. coli and S. aureus, with inhibition zones expanding with BAC concentration and a 100% antibacterial rate. Cell experiments showed normal morphology and adherent growth on patches coated with 0.05%, 0.08%, and 0.1% PA/BAC. Future work will focus on optimizing BAC's concentration range and its low-toxicity modification. In summary, this one-step co-deposition strategy synergistically enhances PP patches' antibacterial and anti-adhesion functions, with simple, mild conditions suitable for industrialization, offering an innovative pathway for functionalizing hernia repair materials.

Key words: hernia repair patch, polypropylene patch, low-temperature plasma treatment, one-step co-deposition, phytic acid, benzalkonium chloride, antibacterial property, medical textiles