Herbal Extract Loaded Chitosan/PEO Nanocomposites as Antibacterial Coatings of Orthopaedic Implants

Abstract

One of the most substantial complications in orthopedic surgeries is implant associated infection. While the implant interface can be a permissive surface for bacterial colonization, an appropriate coating on the implant can effectively hinder biofilm formation. To this aim, henna and thyme extract loaded into a chitosan (CS)/polyethylene oxide (PEO) based nanofibrous hydrogel. CS/PEO/henna and CS/PEO/thymus extract nanofibers were fabricated via two-nozzle electrospinning. The proper weight ratio of CS/PEO/herbal extract was optimized. The appropriate ratio of CS/PEO and the most suitable extract concentrations was obtained to be 7/3 (v/v) and 1 % (v/v), respectively. Contact angle measurements showed an appropriate degree of hydrophilicity in all groups including herbal loaded electrospun nanosheets. Tensile strength measurements showed that inclusion of henna and thymus made minor changes in tensile strength and strain of herbal loaded nanofiber, compared to control CS/PEO fibers. Then antibacterial tests were performed and the fibers either by themselves or when used as coating on orthopedic screws exhibited a good inhibition zone against both gram negative and gram positive bacteria. The coatings showed no adverse effect on the red blood cells in leading to hemolysis. Cytocompatibility assay indicated that the prepared nanofibrous hydrogel coating was absolutely biocompatible as tested with fibroblast cells. The results of this study indicated that our henna and thyme extracts loaded CS/PEO coatings can be used in various medical fields such as wound dressing and implantation coating to prevent bacterial adhesion, growth and generally, infection.