Surface Characterization and Antibacterial Evaluation of Poly(Ethylene Terephthalate) Modified by Chitosan-Immobilization

Abstract

Biomedical PET films were modified by the approach of chitosan-surface-grafting. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) revealed that chitosan molecules were successfully grafted on the PET surface. The bacterial adhesion on the modified surface was evaluated by bacteria plate counting in vitro and scanning electron microscopy (SEM). The results testified that chitosan did make the surface of PET become more antibacterial. The free energy of adhesion (∆Fadh) between the bacteria and the chitosan-immobilized surface of PET was calculated. The value of the ∆Fadh was positive, which suggests that the process of bacterial adhesion on the modified PET surface was not thermodynamically favorable, namely, not spontaneous.

Adhesion and Viability of Two Enterococcal Strains on Covalently Grafted Chitosan and Chitosan/κ-Carrageenan Multilayers

“…The majority of studies on antibacterial properties of polymers and fibers grafted with chitosan were performed in suspension, where the viability of planktonic bacteria is evaluated as a function of the immersion time of the modified substratum in the suspension. Typically, changes in dead/live ratio of the planktonic bacteria in suspension were observed after 2−3 h of immersion. ,, Suspension testing of biomaterials coatings, however, is highly inappropriate for several reasons. First, infection of implants is a surface associated problem and bacteria in a biofilm mode of growth may both phenotypically as well as genotypically differ from their planktonic counterparts in suspension.…”

“…Typically, changes in dead/live ratio of the planktonic bacteria in suspension were observed after 2-3 h of immersion. 6,16,18 Suspension testing of biomaterials coatings, however, is highly inappropriate for several reasons. First, infection of implants is a surface associated problem and bacteria in a biofilm mode of growth may both phenotypically as well as genotypically differ from their planktonic counterparts in suspension.…”

“…Bacterial adhesion and subsequent biofilm formation constitute a source of persistent infections that usually leads to the removal of the infected prosthesis . Several antiadhesive and/or antibacterial coatings have been developed, based on hydrophobicing agents, application of positive charge, polymer brush coatings, , thermoresponsive polymers, drug eluting coatings, silver coatings, natural , or synthetic polymeric biocides, , and many other developments. Yet, the clinical efficacies of many of these coatings still have to be demonstrated.…”

“…Sustainable interest in the biomedical application of chitosans to discourage bacterial adhesion and implant infection is stimulated strongly by the lack of toxicity of chitosans to mammalian cells and its biodegradability and strong antibacterial properties . Covalent grafting of chitosan to chemically inert biomaterials surfaces is usually preceded by grafting of acrylic acid to γ-ray irradiated, plasma, or ozone pretreated surfaces and has been applied to polypropylene, − poly(ethylene terephthalate), , and other polyester fibers. , However, Lin et al reported significant bacterial adhesion after chitosan application to the lumen of oxidized polyethylene tubing and attributed this to higher roughness and positive charge of chitosan-modified surfaces. Considering the known antibacterial properties of chitosan, these observations call for alternative application techniques with enhanced antiadhesive and antibacterial effects.…”