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Medical-grade polyvinyl chloride was surface modified by a multistep physicochemical approach to improve bacterial adhesion prevention properties. This was fulfilled via surface activation by diffuse coplanar surface barrier discharge plasma followed by radical graft copolymerization of acrylic acid through surface-initiated pathway to render a structured high density brush. Three known antibacterial agents, bronopol, benzalkonium chloride, and chlorhexidine, were then individually coated onto functionalized surface to induce biological properties. Various modern surface probe techniques were employed to explore the effects of the modification steps. In vitro bacterial adhesion and biofilm formation assay was performed. Escherichia coli strain was found to be more susceptible to modifications rather than Staphylococcus aureus as up to 85% reduction in adherence degree of the former was observed upon treating with above antibacterial agents, while only chlorhexidine could retard the adhesion of the latter by 50%. Also, plasma treated and graft copolymerized samples were remarkably effective to diminish the adherence of E. coli. (C) 2010 Elsevier B.V. All rights reserved.

A multistep physicochemical approach was adopted to develop a novel surface active antibacterial medical-grade polyvinyl chloride (PVC). This was accomplished through surface activation via diffuse coplanar surface barrier discharge plasma in air at ambient temperature and pressure, followed by radical graft copolymerization of acrylic acid onto the surface via grafting-from pathway to yield a well-defined high density brush. Irgasan as a potent biocide was then coated onto the functionalized surface to impart antimicrobial properties. Contact angle measurements showed an improved hydrophilicity upon multistep modifications. Alterations in surface free energy values were tracked through various known models. The equilibrium water absorption test corroborated the contact angle analysis. Scanning electron microscopy revealed etched features on the plasma treated sample as well as a brush-like pattern on the graft copolymerized surface. Surface chemistry was explored by Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) and X-ray Photoelectron Spectroscopy (XPS), which confirmed the presence of irgasan non-covalently anchored onto the surface. An excellent bacteriostatic performance was exhibited by the irgasan coated sample using the agar diffusion test method against two potentially pathogenic gram-negative and particularly gram-positive bacterial strains implying a facile release of the antibacterial agent. However, in vitro bacterial adhesion and biofilm formation assays indicated incapability of irgasan in hindering the adherence after 24 h incubation. Nevertheless, the plasma treated and graft copolymerized samples were appreciably effective to diminish the adherence of gram-negative strain. Wettability and surface configuration of the substrate, besides bacteria structural characteristics, were established to be crucial factors in the adhesion phenomenon. The irgasan coated medical-grade PVC was suggested to be suited for use in disposable medica