Abstract:The aim of this study was to test, by an in vitro approach, whether a natural extract derived from eggs of the mollusc Cryptomphalus aspersa (e-CAF) that seems to present regenerative properties, can enhance the mobilization of human hair dermal papilla cells (HHDPCs) and play a role on tissue repair and regeneration. We have tested HHDPCs proliferation by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium-bromide (MTT) assay; cell migration by using a wound healing assay, as well as the modulation of the expression of cytoskeletal (F-actin and vimentin) and cell adhesion to the extracellular matrix (ECM) (vinculin and P-FAK) proteins. We also explored whether e-CAF could lead HHDPCs to keratinocytes and/or fibroblasts by evaluating the expression of specific markers. We have compared these e-CAF effects with those induced by TGFβ 1 , implicated in regulation of cell proliferation and migration. e-CAF promotes proliferation and migration of HHDPCs cells in a time-and dose-dependent manner; it also increases the migratory behavior and the expression of adhesion molecules. These results support the fact that e-CAF could play a role on skin regeneration and be used for the prevention or repair of damaged tissue, either due to external causes or as a result of cutaneous aging.

This work presents a practical methodology to produce multilevel hierarchical structures with precise control of the structural geometry at every level by combining photo and nanoimprint lithography processes. The method involves sequential steps of nanoimprinting of a first deposited polymer layer followed by nanoimprinting of a second deposited layer of a photoresin and, afterward, performing on this layer optical lithography by means of a maskless laser writer to pattern micrometer-size features. A hierarchical topography is consequently obtained comprising nanopatterns and micropatterns at different levels designed independently with very high feature control. The process can be repeated sequentially employing hierarchical working molds produced on a previous fabrication cycle to produce multilevel self-similar hierarchical topographies in a sort of fractal growing manner. The patterning method has broad applicability, as exemplary demonstration, superhydrophobicity, and anisotropic wetting behavior are revealed.

In recent years, the understanding of the bactericidal mechanisms of natural surfaces has received great attention to unravel their design principles for the development of next‐generation mechano‐bactericidal surfaces. Due to the difficulty in characterizing the bacteria–nanostructure interface, many aspects of the physical interaction between bacteria and the surface, and the underlying bactericidal mechanisms, remain unclear. This study focuses on evaluating the dynamics of the mechano‐bactericidal process in the case of the moth‐eye bioinspired topography in relation to the bacteria strain and mechanical characteristics of the surface. The bacteria–nanostructure interface is examined by measuring the deformations inflicted by the nanotopography on the bacterial wall upon attachment using two techniques, namely atomic force microscopy and stereometric analysis of scanning electron microscopy images. All data match well and are in accordance with the expected bacteria mechanical deformation calculated by finite element modeling. This represents a practical methodology to measure bacterial deformations inflicted by nanotopography. The methodology can be implemented to any other bacteria strain or bactericidal topography to verify the degree of mechanical stress and bactericidal efficacy related to the topography and surface stiffness and may serve as a design basis for the fabrication of effective antibacterial surfaces.

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