Electrospun polycaprolactone coated with gum tragacanth containing layered double hydroxide/thymol nanohybrid for wound dressing application.

Incorporating a nanohybrid containing a natural antibacterial agent into nanofibrous scaffolds can synergistically affect wound healing. In this study, polycaprolactone (PCL) nanofibrous membranes were fabricated via electrospinning. Gum-tragacanth (GT)-containing thymol (Thy)-loaded layered double hydroxide (LDH) nanohybrids were coated on the nanofiber surface, which provided a sustained thymol release. The LDH/Thy nanohybrids were prepared using a co-precipitation method. LDH/Thy was added to the GT solution at different concentrations (0, 0.1, 1, and 10 % w/v, followed by dip-coating onto PCL nanofiber surfaces. The nanofibers were characterized using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and energy-dispersive X-ray spectroscopy (EDX). These mats were evaluated for their hydrophilicity, in vitro drug release, mechanical and antibacterial properties, cytocompatibility, cell attachment, and in vivo wound healing performance. Results demonstrated that the inclusion of LDH/Thy significantly improved the hydrophilicity. The mechanical study showed that adding LDH (10 %) nanoparticles to PCL/GT nanofibers increased tensile strength from 0.27 to 1.74 MPa, respectively. In addition, the PCL/GT/LDH/Thy nanofibers exhibited superior antibacterial activity against Escherichia coli (Gram-negative), Staphylococcus aureus (Gram-positive), and methicillin-resistant Staphylococcus aureus (MRSA), which correlated with the sustained release of thymol (78 % over 110 h). Moreover, after five days, the nanofibers showed no cytotoxic activity against the L929 mouse fibroblast cell line and provided an appropriate microenvironment for cell attachment. The animal study results revealed that the average wound healing rate of PCL/GT/LDH/Thy nanofibers significantly increased compared to the control group on the 10th day post-treatment (from 80.33 % to 48.5 %, respectively), along with improved wound closure quality. The synergistic effect of PCL/GT/LDH/Thy could provide helpful information and implications for promoting their application in wound dressings.