Combining antibacterial and wound healing features: Xanthan gum/guar gum 3D-printed scaffold tuned with hydroxypropyl-β-cyclodextrin/thymol and Zn2+

Abstract

Biofilm formation on biological and material surfaces represents a heavy health and economic burden for both patient and society. To contrast this phenomenon, medical devices combining antibacterial and pro-wound healing abilities are a promising strategy. In the present work, Xanthan gum/Guar gum (XG/GG)-based scaffolds were tuned with thymol and Zn2+ to obtain wound dressings that combine antibacterial and antibiofilm properties and favour the healing process. The tuning process preserved the 3D extrusion-based printability of the XG/GG ink. Scaffolds swelling profile was assessed in PBS pH 7.4, and the resistance to compressive forces was studied using a texturometer. The scaffolds microarchitectures were analyzed by SEM, while ATR-FTIR spotlighted the chemical modifications of the customized materials. Thymol and Zn2+ release was analyzed in biologically relevant media, showing a burst release in the first hours. The antibacterial properties were confirmed against S. aureus, P. aeruginosa, and S. epidermidis by isothermal microcalorimetry and biofilm viable cell counting. Incorporation of hydroxypropyl-β-cyclodextrin (HPβCD) improved thymol loading (7- and 14- times higher thymol content) and enhanced the antimicrobial and antioxidant performances of the dressing, while the presence of Zn2+ strongly potentiated the antimicrobial activity, showing a potent antibiofilm response in both Gram-positive and Gram-negative strains of clinical concern. The thymol and Zn2+ combination led to a reduction of 99.95 %, 99.99 %, and 98.26 %, of biofilm formation against S. aureus, P. aeruginosa, and S. epidermidis, respectively. Furthermore, the scaffolds demonstrated good hemocompatibility, cytocompatibility, tissue integration and pro-angiogenic features in an in ovo CAM model.