The construction of functional micro- or nanostructured surfaces is extensively studied since they are able to provide multifunctional properties and for large variety of potential applications in fields such as tissue engineering, wearable electronics or microfluidics. The micro- or nanosized surfaces can be easily prepared by various lithography techniques, also additional modifications (laser exposure, metal deposition and further processing) and which can induce new applicable properties on the basis of synergic effect by combining aforementioned approaches. In this work we have focused on the polytetrafluoroethylene (PTFE) nanotextile with specific bimetallic nanostructures. Our primary target was to find optimal surface modification of silver/gold coated surface, which would induce strong antibacterial response to both gram-positive and/or gram-negative bacteria. We have used plasma-modified polytetrafluoroethylene nanotextile as a substrate, onto which silver and gold nanolayers were deposited by sputtering. The foils were further subjected to "single-shot" exposure to an excimer KrF laser and some samples were also thermally stressed before exposure. Such surfaces were further examined in terms of surface morphology and chemical composition. The surface was investigated for antibacterial properties. Their antimicrobial activity was examined in vitro against the bacteria Escherichia coli and Staphylococcus epidermidis strains. The surface of the prepared materials was replicated into a lactic acid polymer and the properties were again investigated in terms of surface morphology and surface chemistry. The results demonstrated construction of antibacterial surfaces with excellent resistance to bacteria E. coli for bimetallic structures on PTFE. Excimer laser induced bimetallic pattern exhibited also significant antibacterial properties for S. epidermidis. Replication of bimetallic pattern was also demonstrated.

• Keywords
• Antibacterial properties, Bimetallic nanopattern, Laser exposure, Nanostructure, Nanotextile, Noble metal, PTFE, Polymer, Replication,
• Publication type
• Journal Article MeSH

Here, we present surface analysis and biocompatibility evaluation of novel composite material based on graphene oxide traded as BioHastalex. The pristine material's surface morphology and surface chemistry were examined by various analytical methods. The BioHastalex with a thin silver layer was subsequently heat treated and characterized, the impact on the material surface wettability and morphology was evaluated. Significant surface roughness and morphology changes were detected at the nanometer scale after heat treatment of Ag-sputtered BioHastalex. The deposition of a thin silver nanolayer had an outstanding effect on BioHastalex's antibacterial properties while still maintaining cell viability (MRC-5, HaCaT). The heat treatment of BioHastalex-Ag led to the formation of regular nanocluster arrays while affecting the Ag concentration on the very surface. The decrease in silver concentration was connected with the length of heat treatment; cells growing on such samples exhibited good viability, and the antibacterial properties were weaker than simply sputtered BioHastalex.

• Keywords
• BioHastalex, Cytocompatibility, Graphene composite, Morphology, Nanostructure, Polymer stability, Surface chemistry, Surface modification,
• Publication type
• Journal Article MeSH