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Directing polymer self-assembly through noncovalent interactions is a powerful way to control the structure and function of nanoengineered materials. Dynamic hydrogen bonds are particularly useful for materials with structures that change over time or in response to specific stimuli. In the present work, we use the supramolecular association of urea moieties to manipulate the morphology, thermal response, and mechanical properties of soft polymeric hydrogels. Urea-terminated poly(isopropyl glycidyl ether)- b -poly(ethylene oxide)- b -poly(isopropyl glycidyl ether) ABA triblock copolymers were synthesized using controlled, anionic ring-opening polymerization and subsequent chain-end functionalization. Triblock copolymers with hydroxy end-groups were incapable of hydrogelation, while polymers terminated with meta -bis-urea motifs formed robust gels at room temperature. Rheometric analysis of the bulk gels, variable-temperature infrared spectroscopy (VT-IR), differential scanning calorimetry (DSC), and small-angle X-ray scattering (SAXS) confirmed the formation of structured hydrogels via association of the meta -bis-urea end-groups. Monourea end-groups did not result in the same regular structure as the meta -bis-urea. In future, the reported hydrogels could be useful for elastomeric, shape-morphing 3D-printed constructs, or as biomimetic scaffolds with precisely tailored porosity and mechanical properties. 

Abstract Engineered living materials (ELMs) have broad applications for enabling on‐demand bioproduction of compounds ranging from small molecules to large proteins. However, most formulations and reports lack the capacity for storage beyond a few months. In this study, we develop an optimized procedure to maximize stress resilience of yeast‐laden ELMs through the use of desiccant storage and 10% trehalose incubation before lyophilization. This approach led to over 1‐year room temperature storage stability across a range of strain genotypes. In particular, we highlight the superiority of exogenously added trehalose over endogenous, engineered production in yielding robust preservation resilience that is independent of cell state. This simple, effective protocol enables sufficient accumulation of intracellular trehalose over a short period of contact time across a range of strain backgrounds without requiring the overexpression of a trehalose importer. A variety of microscopic analysis including µ‐CT and confocal microscopy indicate that cells form spherical colonies within F127‐BUM ELMs that have variable viability upon storage. The robustness of the overall procedure developed here highlights the potential for widespread deployment to enable on‐demand, cold‐chain independent bioproduction.