The synthesis of hybrid hydrogels by pH-controlled structural transition with exceptional rheological properties as cellular matrix is reported. “Depsi” peptide sequences are grafted onto a polypeptide backbone that undergo a pH-induced intramolecular O–N–acyl migration at physiological conditions affording peptide nanofibers (PNFs) as supramolecular gelators. The polypeptide–PNF hydrogels are mechanically remarkably robust. They reveal exciting thixotropic behavior with immediate in situ recovery after exposure to various high strains over long periods and self-repair of defects by instantaneous reassembly. High cytocompatibility, convenient functionalization by coassembly, and controlled enzymatic degradation but stability in 2D and 3D cell culture as demonstrated by the encapsulation of primary human umbilical vein endothelial cells and neuronal cells open many attractive opportunities for 3D tissue engineering and other biomedical applications.
The authors are grateful to the financial support by the Baden-Württemberg Stiftung (BioMatS-15), by the Horizon 2020 project “AD GUT”, and by the Volkswagen foundation project 89943.
Chemical toolbox for creating versatile protein nanostructures
Protein nanostructures are ubiquitous in biological systems and serve many functions. Inspired by Nature, scientists have devised synthetic approaches to derive functional and well-defined protein nanostructures for a broad range of applications including imaging, catalysis and in medicine. In the review article by Kuan, Bergamini and Weil, a step-by-step guide on the design principles of preparing synthetic protein nanostructures and their resultant impact in biomedical applications are highlighted.
The authors are grateful to the financial support by the Max Planck Society, German National Foundation (Sonderforschungsbereich 1279), the ERC Synergy Grant (319130-BioQ), the European Union Research and Innovation Program “Horizon 2020” and Marie Curie International Training Network “ProteinConjugates”
A versatile, bottom-up approach allows the controlled fabrication of polydopamine (PD) nanostructures on DNA origami. PD is a biosynthetic polymer that has been investigated as an adhesive and promising surface coating material. However, the control of dopamine polymerization is challenged by the multistage-mediated reaction mechanism and diverse chemical structures in PD.DNA origami decorated with multiple horseradish peroxidase-mimicking DNAzyme motifs was used to control the shape and size of PD formation with nanometer resolution. These fabricated PD nanostructures can serve as “supramolecular glue” for controlling DNA origami conformations. Facile liberation of the PD nanostructures from the DNA origami templates has been achieved in acidic medium. This presented DNA origami controlled polymerization of a highly cross-linked polymer provides a unique access towards anisotropic PD architectures with distinct shapes that were retained even in the absence of the DNA origami template.
The authors are grateful to the financial support by the European Research Council (ERC) under the program Synergy Grant 319130-BioQ and the BMBF project “Selekomm” within the Biotechnologie 2020 + initiative.