PhD Thesis Presentation - Bioinspired Materials from the Hybrid of Polymers and Self-assembling Peptides

It has been a long pursuit for scientists to synthesize desired materials from molecular design. Hybrid of materials has aroused wide interest for the construction of modular and complex materials with synergistic merits. The hybrid of polymers and peptides has largely been investigated and applied for the bottom-up design of a plethora of materials with desired applications, including controlled release, tissue engineering, electronics, catalysis and separation. In this thesis, I focus on the use of bioinspired polymer-oligopeptide hybrid to fabricate two types of materials, namely, hydrogel and micron-sized liquid droplet, derived from peptides with strong and weak molecular interactions, respectively. Firstly, I introduce a new hybrid hydrogel from dextran crosslinked by amyloid-inspired self-assembling peptide. The length of peptide crosslinker can be readily modulated by ultrasonic treatment, whereby the mechanical strength, self-healing and shear-thinning properties of hybrid hydrogels are tuned. Secondly, I introduce the first synthesis of minimalist artificial membraneless organelle (AMO) from intrinsically disordered protein-mimicking polymer-oligopeptide hybrid (IPH), driven by liquid-liquid phase separation (LLPS). The relationship between molecular structure of IPH and phase behavior is studied. In addition, AMO formed from phase-separated IPH is capable of recruitment and release of biological macromolecules, as well as compartmentalization and enhancement of biochemical reaction. Moreover, AMO demonstrates similar behavior as natural membraneless organelle (MO) in the presence of nucleic acids, namely, modulated propensity of LLPS, liquidity and dynamics. Lastly, AMO can enrich, recruit and release cargoes spanning a wide range of nature, including small fluorophores, fluorophore-labeled polymers, proteins, DNAs and RNAs, as well as control aggregation-induced emission (AIE) from the regulation of the aggregation state of AIE luminogen via tuning LLPS. Taken together, these new bioinspired material platforms open up new pathways for connecting polymer-peptide hybrid with fields ranging from fundamental understanding of material properties, tissue engineering, biochemical catalysis, biomolecule storage and controlled release to AIE.