Cell Adhesion Behaviors on Spider Silk Fibers, Films, and Nanofibers.

Silk-based materials have garnered attention for use as medical supplies due to their mechanical toughness and low cytotoxicity. Silkworm silk has been applied as surgical sutures for decades. In contrast, the utilization of spider silk is limited mainly because of its scarcity. Although the biomimicry of spider silk has been developed using recombinant protein expression systems with the use of genetic engineering, the product often results in lower molecular weight and a lack of the N- or C-terminal regions. The incomplete sequence of the spider silk-like protein prevents the objective evaluation of the native spider silk as a medical application and retards the development of spider silk-inspired materials. Here, we reeled the native spider silk directly from live spiders and investigated the cell adhesion behavior based on three kinds of surface topography of spider silk-based substrates, namely, fibers, films, and non-woven fabrics. The cell adhesion behavior was largely influenced by the surface micro/nanostructure rather than the wettability of the surface. This study will contribute to promote the utilization of spider silk in the medical field as a candidate for promising bio-based fibers in the context of sustainable development goals.

Preparation of patterned zinc oxide films by breath figure templating.

A large variety of microporous polymer films can be prepared by the breath figure technique. Here, we report on its use for the formation of microporous zinc oxide films. Zinc acetylacetonate, a zinc oxide precursor, is either dissolved in a polymer solution that is cast at high humidity to form microporous films or is vacuum evaporated onto a preformed microporous polymer film. Annealing leads to the pyrolysis of the organic material and the formation of zinc oxide films, which show increased photocatalytic activity as compared to unstructured films.