Hard-soft tissue interfaces pose unique challenges for regeneration due to architectural, mechanical, and compositional changes between tissues, which are difficult to incorporate into tissue engineering scaffolds. Multiphasic scaffolds are needed to better mimic structural and chemical changes through the incorporation of layers with distinct properties. A particular challenge in the production of multilayered constructs is achieving cohesion between layers. Herein, a novel system is developed, which combines sequential collagen self-assembly and diffusion gradients in mineralization to produce multiphasic collagen scaffolds that have intrinsic connectivity and porosity between layers, with no need for adhesives or heat treatments. The scaffolds incorporate mineralized layers, wherein the mineralized collagen fibrils have intrafibrillar oriented mineral resembling bone, alongside unmineralized layers. The interface between mineralized and unmineralized layers is sharp and well defined, with nonmineralized fibrils inserting into the mineralized layer to create mechanical interlock and cohesion. Inspired by the complex architecture of the periodontal attachment apparatus (bone-ligamentcementum), it is demonstrated that the model system can be applied to the development of a trilayered collagen scaffold with potential for periodontal regeneration.

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In article number https://doi.org/10.1002/adfm.201804730, Eli D. Sone and co‐workers report on the development of biomimetic collagen scaffolds that incorporate bone‐like mineralized layers alongside unmineralized layers, resembling hard‐soft connective tissue interfaces. The boundary between mineralized and unmineralized layers is well defined, with unmineralized collagen fibrils intermingling with the mineralized layer to create mechanical interlock without need for adhesives.

Recent studies have demonstrated silk fibroin’s ability to extend the shelf life of foods by mitigating the hallmarks of spoilage, namely oxidation and dehydration. Due to the potential for this protein to become more widespread, its safety was evaluated comprehensively. First, a bacterial reverse mutation test (Ames test) was conducted in five bacterial strains. Second, an in vivo erythrocyte test was conducted with Sprague Dawley rats at doses up to 1,000mg/kg-bw/day. Third, a range-finder study was conducted with Sprague Dawley rats at the highest consumption amount given solubility and oral gavage volume constrains (500mg/kg-bw/day). Fourth, a 28-day study in Sprague Dawley rats was conducted at the 500mg/kg-bw/day amount. Fifth, an in vitro pepsin digestion assay was performed to assess the potential for protein allergenicity. Sixth, allergenic potential was further assessed using liquid chromatography-mass spectroscopy for detection of allergenic insect proteins. Seventh, the protein sequences were subjected to bioinformatic analyses. Together, these studies raise no mutagenic, carcinogenic, toxicological, or allergenic concerns with the oral consumption of silk fibroin.