Highly Adhesive Amyloid-Polyphenol Hydrogels for Cell Scaffolding.

Rationally designing microstructures of soft hydrogels for specific biological functionalization is a challenge in tissue engineering applications. A novel and affordable soft hydrogel scaffold is constructed here by incorporating polyphenol modules with lysozyme amyloid fibrils (Lys AFs) via non-covalent self-assembly. Embedded polyphenols not only trigger hydrogel formation but also determine gel behavior by regulating the polyphenol gallol density and complex ratio. The feasibility of using a polyphenol-Lys AF hydrogel as a biocompatible cell scaffold, which is conducive to cell proliferation and spreading, is also shown. Notably, introducing polyphenols imparts the corresponding hydrogels a superior cell bioadhesive efficiency without further biofunctional decoration and thus may be successfully employed in both healthy and cancer cell lines. Confocal laser scanning microscopy also reveals that the highly expressed integrin-mediated focal adhesions form due to stimulation of the polyphenol-AF composite hydrogel, direct cell adhesion, proliferation, and spreading. Overall, this work constitutes a significant step forward in creating highly adhesive tissue culture platforms for in vitro culture of different cell types and may greatly expand prospects for future biomaterial design and development.

Versatile Mechanically Tunable Hydrogels for Therapeutic Delivery Applications.

Hydrogels provide a versatile platform for biomedical material fabrication that can be structurally and mechanically fine-tuned to various tissues and applications. Applications of hydrogels in biomedicine range from highly dynamic injectable hydrogels that can flow through syringe needles and maintain or recover their structure after extrusion to solid-like wound-healing patches that need to be stretchable while providing a selective physical barrier. In this study, a toolbox is designed using thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) polymeric matrices and nanocelluloses as reinforcing agent to obtain biocompatible hydrogels with altering mechanical properties, from a liquid injectable to a solid-like elastic hydrogel. The liquid hydrogels possess low viscosity and shear-thinning properties at 25 °C, which allows facile injection at room temperature, while they become viscoelastic gels at body temperature. In contrast, the covalently cross-linked solid-like hydrogels exhibit enhanced viscoelasticity. The liquid hydrogels are biocompatible and are able to delay the in vitro release and maintain the bioactivity of model drugs. The antimicrobial agent loaded solid-like hydrogels are effective against typical wound-associated pathogens. This work presents a simple method of tuning hydrogel mechanical strength to easily adapt to applications in different soft tissues and broaden the potential of renewable bio-nanoparticles in hybrid biomaterials with controlled drug release capabilities.