Engineering High Strength and Super-Toughness of Unfolded Structural Proteins and their Extraordinary Anti-Adhesion Performance for Abdominal Hernia Repair.

The utility of unfolded structural proteins with diverse sequences offers multiple potentials to create functional biomaterials. However, it is challenging to overcome their structural defects for the development of biological fibers with a combination of high strength and high toughness. Herein, robust fibers from a recombinant unfolded protein consisting of resilin and supercharged polypeptide are fabricated via wet-spinning approaches. Particularly, the highly ordered structures induced by supramolecular complexation significantly improve the fiber's mechanical performance. In contrast to chemical fibers with high strength and low toughness (or vice versa), the present fibers demonstrate exceptional high strength and super-toughness, showing a breaking strength of ≈550 MPa and a toughness of ≈250 MJ m-3 , respectively, surpassing many polymers and artificial protein fibers. Remarkably, the outstanding biocompatibility and superior mechanical properties allow application of the constructed fiber patches for efficient abdominal hernia repair in rat models. In stark contrast to clinical patches, there is no observed tissue adhesion by this treatment. Therefore, this work provides a new type of engineered protein material for surgical applications.

Ultra-strong bio-glue from genetically engineered polypeptides.

The development of biomedical glues is an important, yet challenging task as seemingly mutually exclusive properties need to be combined in one material, i.e. strong adhesion and adaption to remodeling processes in healing tissue. Here, we report a biocompatible and biodegradable protein-based adhesive with high adhesion strengths. The maximum strength reaches 16.5 ± 2.2 MPa on hard substrates, which is comparable to that of commercial cyanoacrylate superglue and higher than other protein-based adhesives by at least one order of magnitude. Moreover, the strong adhesion on soft tissues qualifies the adhesive as biomedical glue outperforming some commercial products. Robust mechanical properties are realized without covalent bond formation during the adhesion process. A complex consisting of cationic supercharged polypeptides and anionic aromatic surfactants with lysine to surfactant molar ratio of 1:0.9 is driven by multiple supramolecular interactions enabling such strong adhesion. We demonstrate the glue's robust performance in vitro and in vivo for cosmetic and hemostasis applications and accelerated wound healing by comparison to surgical wound closures.