Biomimetic Polymer Surfaces by High Resolution Molding of the Wings of Different Cicadas

Rose Petal Mimetic Surfaces with Antibacterial Properties Produced Using Nanoimprint Lithography

In this study, we produced bioinspired micro/nanotopography on the surface of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) films and demonstrated that these films display antibacterial properties. In the first step, structures that are found on the surface of a rose petal were copied on the surface of PVDF-HFP films. Following this, a hydrothermal method was used to grow ZnO nanostructures on top of this rose petal mimetic surface. The antibacterial behavior of the fabricated sample was demonstrated against Gram-positive Streptococcus agalactiae (S. agalactiae) and Gram-negative Escherichia coli (E. coli) as model bacteria. For comparison purposes, the antibacterial behavior of a neat PVDF-HFP film was also investigated against both bacterial species. The results show that the presence of rose petal mimetic structures on PVDF-HFP helped the material to display improved antibacterial performance against both S. agalactiae and E. coli compared to the antibacterial performance of neat PVDF-HFP. The antibacterial performance was further enhanced for samples that had both rose petal mimetic topography and ZnO nanostructures on the surface.

Designing Effective Antimicrobial Nanostructured Surfaces: Highlighting the Lack of Consensus in the Literature

Research into nanostructured materials, inspired by the topography of certain insect wings, has provided a potential pathway toward drug-free antibacterial surfaces, which may be vital in the ongoing battle against antimicrobial resistance. However, to produce viable antibacterial nanostructured surfaces, we must first understand the bactericidal mechanism of action and how to optimize them to kill the widest range of microorganisms. This review discusses the parameters of nanostructured surfaces that have been shown to influence their bactericidal efficiency and highlights the highly variable nature of many of the findings. A large-scale analysis of the literature is also presented, which further shows a lack of clarity in what is understood about the factors influencing bactericidal efficiency. The potential reasons for the ambiguity, including how the killing effect may be a result of multiple factors and issues with nonstandardized testing of the antibacterial properties of nanostructured surfaces, are then discussed. Finally, a standard method for testing of antimicrobial killing is proposed that will allow comparison between studies and enable a deeper understanding about nanostructured surfaces and how to optimize their bactericidal efficiency.

Nanoimprint lithography-based replication techniques for fabrication of metal and polymer biomimetic nanostructures for biosensor surface functionalization

Nanostructuring is a promising and successful approach to tailor functional layers and to improve the characteristics of biosensors such as signal transmission and tighter cell-surface coupling. One of the major objectives in biosensing and tissue engineering is the development of interfaces that mimic the natural environment of biosystems composed of extracellular matrix biomolecules. Nevertheless, effective techniques to reconstruct the random distribution of these biomolecules are still not well established. For this reason, the presented work demonstrates different methods based on nanoimprint lithography to replicate randomly distributed natural nanostructures with complex geometries into different polymers and metals. The fidelity of the replicated nanostructures has been evaluated by atomic force microscopy and the attributes of the fabrication processes have been discussed. Finally, different replication techniques have been combined for the biomimetic nanostructuring of the dielectric passivation layer as well the metal electrode surface to develop novel whole-surface-nanostructured microelectrode arrays.