Expanding the molecular language of protein liquid-liquid phase separation.

Understanding the relationship between a polypeptide sequence and its phase separation has important implications for analysing cellular function, treating disease and designing novel biomaterials. Several sequence features have been identified as drivers for protein liquid-liquid phase separation (LLPS), schematized as a 'molecular grammar' for LLPS. Here we further probe how sequence modulates phase separation and the material properties of the resulting condensates, targeting sequence features previously overlooked in the literature.

Sequence-Encoded Differences in Phase Separation Enable Formation of Resilin-like Polypeptide-Based Microstructured Hydrogels.

Microstructured hydrogels are promising platforms to mimic structural and compositional heterogeneities of the native extracellular matrix (ECM). The current state-of-the-art soft matter patterning techniques for generating ECM mimics can be limited owing to their reliance on specialized equipment and multiple time- and energy-intensive steps. Here, a photocross-linking methodology that traps various morphologies of phase-separated multicomponent formulations of compositionally distinct resilin-like polypeptides (RLPs) is reported.

Recombinant protein-based injectable materials for biomedical applications.

Injectable nanocarriers and hydrogels have found widespread use in a variety of biomedical applications such as local and sustained biotherapeutic cargo delivery, and as cell-instructive matrices for tissue engineering. Recent advances in the development and application of recombinant protein-based materials as injectable platforms under physiological conditions have made them useful platforms for the development of nanoparticles and tissue engineering matrices, which are reviewed in this work. Protein-engineered biomaterials are highly customizable, and they provide distinctly tunable rheological properties, encapsulation efficiencies, and delivery profiles.

Alteration of Microstructure in Biopolymeric Hydrogels Compositional Modification of Resilin-Like Polypeptides.

Heterogeneities in hydrogel scaffolds are known to impact the performance of cells in cell-laden materials constructs, and we have employed the phase separation of resilin-like polypeptides (RLPs) as a means to generate such materials. Here, we study the compositional features of resilin-like polypeptides (RLPs) that further enable our control of their liquid-liquid phase separation (LLPS) and how such control impacts the formation of microstructured hydrogels. The evaluation of the phase separation of RLPs in solutions of ammonium sulfate offers insights into the sequence-dependent LLPS of the RLP solutions, and atomistic simulations, along with 2D-nuclear Overhauser effect spectroscopy (NOESY) and correlated spectroscopy (COSY) H NMR, suggest specific amino acid interactions that may mediate this phase behavior.

Methods for producing microstructured hydrogels for targeted applications in biology.

Hydrogels have been broadly studied for applications in clinically motivated fields such as tissue regeneration, drug delivery, and wound healing, as well as in a wide variety of consumer and industry uses. While the control of mechanical properties and network structures are important in all of these applications, for regenerative medicine applications in particular, matching the chemical, topographical and mechanical properties for the target use/tissue is critical. There have been multiple alternatives developed for fabricating materials with microstructures with goals of controlling the spatial location, phenotypic evolution, and signaling of cells.