Inhibition of biofilm growth of Gram-positive and Gram-negative bacteria on tuned polyurethane nanofibers

Biofilm formation is a process of bacterial attachment whereby they fasten irreversibly to a biomaterial surface and lead to unwanted phenotypic changes. The chief concern is its formation and to prevent the harmful changes that follow the accumulation of bacteria on implants, so the scientific community has made efforts. In this study, we attempted to fabricate a novel tissue engineering candidate to prevent the biofilm formation desired by ideal biomaterials. We prepared the micro/nanofibers of polyurethane (PU) incorporated with hydrophilic beta-cyclodextrin (CD) by electrospinning technique. Further on, these as-spun fibers were in fused with an antibacterial agent. As an antibacterial agent, silver nanoparticles (Ag NPs) were adsorbed on scaffolds. Among the varied methods of its adsorption, adsorption by sonication and hydrothermal process were chosen. Characterization studies performed were scanning electron microscopy (SEM) and water contact angle analysis. The uniform morphology of nanofibers was seen in SEM micrographs which mimics the extracellular matrix. The hydrophilicity test showed the increased hydrophilicity of scaffolds with a decrease in contact angle in CD and Ag NPs incorporated fibre scaffolds. The Ag release assay showed slow release in the case of the fibers where Ag was adsorbed by hydrothermal treatment compared to adsorption by sonication. The antibacterial tests show inhibition of bacteria to different degrees by the fibers. The highest zones were seen in the case of samples with Ag NPs adsorption by sonication. The in vitro MTT assay presented that these scaffolds were non-toxic to the cells and could be employed in biological applications.