Sensing the difference: the influence of anisotropic cues on cell behavior

From tissue morphogenesis to homeostasis, cells continuously experience and respond to physical, chemical and biological cues commonly presented in gradients. In this article we focus our discussion on the importance of nano/micro topographic cues on cell activity, and the role of anisotropic milieus play on cell behavior, mostly adhesion and migration. We present the need to study physiological gradients in vitro. To do this, we review different cell migration mechanisms and how adherent cells react to the presence of complex tissue-like environments and cell-surface stimulation in 2D and 3D (e.g. ventral/dorsal anisotropy)

Biomineralization of engineered spider silk protein-based composite materials for bone tissue engineering

Materials based on biodegradable polyesters such as poly(butylene terephthalate) (PBT) or poly(butylene terephthalate-co-poly(alkylene glycol) terephthalate) (PBTAT) have potential application as pro-regenerative scaffolds for bone tissue engineering. Herein is reported the preparation of films composed of PBT or PBTAT and an engineered spider silk protein, (eADF4(C16)), that displays multiple carboxylic acid moieties capable of binding calcium ions and facilitating their biomineralization with calcium carbonate or calcium phosphate. Human mesenchymal stem cells cultured on films mineralized with calcium phosphate show enhanced levels of alkaline phosphatase activity suggesting that such composites have potential use for bone tissue engineering

Facile Photochemical Modification of Silk Protein–Based Biomaterials

Silk protein–based materials show promise for application as biomaterials for tissue engineering. The simple and rapid photochemical modification of silk protein–based materials composed of either Bombyx mori silkworm silk or engineered spider silk proteins (eADF4(C16)) is reported. Radicals formed on the silk‐based materials initiate the polymerization of monomers (acrylic acid, methacrylic acid, or allylamine) which functionalize the surface of the silk materials with poly(acrylic acid) (PAA), poly(methacrylic acid) (PMAA), or poly(allylamine) (PAAm). To demonstrate potential applications of this type of modification, the polymer‐modified silks are mineralized. The PAA‐ and PMAA‐functionalized silks are mineralized with calcium carbonate, whereas the PAAm‐functionalized silks are mineralized with silica, both of which provide a coating on the materials that may be useful for bone tissue engineering, which will be the subject of future investigations

On the routines of wild-type silk fibroin processing toward silk-inspired materials: a review

For years, silk fibroin of a domestic silkworm, Bombyx mori, has been recognized as a valuable material and extensively used. In the last decades, new application fields are emerging for this versatile material. Those final, specific applications of silk dictate the way it has been processed in industry and research. This review focuses on the description of various approaches for silk downstream processing in a laboratory scale, that fall within several categories. The detailed description of workflow possibilities from the naturally found material to a finally formulated product is presented. Considerable attention is given to (bio-) chemical approaches of silk fibroin transformation, particularly, to its enzyme-driven modifications. The focus of the current literature survey is exclusively on the methods applied in research and not industry

Engineered spider silk protein-based composites for drug delivery

Silk protein-based materials are promising materials for the delivery of drugs and other active ingredients, due to their processability, biocompatibility, and biodegradability. The preparation of films composed of an engineered spider silk protein (eADF4(C16)) in combination with either a polyester (polycaprolactone) or a polyurethane (pellethane), and their physical properties are described. The release profiles are affected by both the film composition and the presence of enzymes, and release can be observed over a period of several weeks. Such silk-based composites have potential as drug eluting biocompatible coatings or implantable devices

Glycopolymer functionalization of engineered spider silk protein-based materials for improved cell adhesion

Silk protein-based materials are promising biomaterials for application as tissue scaffolds, due to their processability, biocompatibility, and biodegradability. The preparation of films composed of an engineered spider silk protein (eADF4(C16)) and their functionalization with glycopolymers are described. The glycopolymers bind proteins found in the extracellular matrix, providing a biomimetic coating on the films that improves cell adhesion to the surfaces of engineered spider silk films. Such silk-based materials have potential as coatings for degradable implantable devices