Antibacterial and antibiofouling clay nanotube–silicone composite

CJ Boyer,1 J Ambrose Jr,2 S Das,1 A Humayun,1 D Chappidi,1 R Giorno,3 DK Mills2,3 1Molecular Science and Nanotechnology, College of Engineering & Science, Louisiana Tech University, Ruston, LA, USA; 2Center for Biomedical Engineering and Rehabilitation Science, Louisiana Tech University, Ruston, LA, USA; 3School of Biological Sciences, Louisiana Tech University, Ruston, LA, USA Introduction: Invasive medical devices are used in treating millions of patients each day. Bacterial adherence to their surface is an early step in biofilm formation that may lead to infection, health complications, longer hospital stays, and death. Prevention of bacterial adherence and biofilm development continues to be a major healthcare challenge. Accordingly, there is a pressing need to improve the anti-microbial properties of medical devices. Materials and Methods: Polydimethylsiloxane (PDMS) was doped with halloysite nanotubes (HNTs), and the PDMS-HNT composite surfaces were coated with PDMS-b-polyethylene oxide (PEO) and antibacterials. The composite material properties were examined using SEM, energy dispersive spectroscopy, water contact angle measurements, tensile testing, UV-Vis spectroscopy, and thermal gravimetric analysis. The antibacterial potential of the PDMS-HNT composites was compared to commercial urinary catheters using cultures of E. coli and S. aureus. Fibrinogen adsorption studies were also performed on the PDMS-HNT-PEO composites. Results: HNT addition increased drug load during solvent swelling without reducing material strength. The hydrophilic properties provided by PEO were maintained after HNT addition, and the composites displayed protein-repelling properties. Additionally, composites showed superiority over commercial catheters at inhibiting bacterial growth. Conclusion: PDMS-HNT composites showed superiority regarding their efficacy at inhibiting bacterial growth, in comparison to commercial antibacterial catheters. Our data suggest that PDMS-HNT composites have potential as a coating material for anti-bacterial invasive devices and in the prevention of institutional-acquired infections. Keywords: antibacterials, halloysite, medical devices, nanocomposites, PDM