Molecular Control on Stress Relaxation Behavior of Collagen-inspired Biohybrid Hydrogels
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초록
내용
Biological soft materials, such as extracellular matrix (ECM), exhibit viscoelastic properties, including stress relaxation. Understanding stress relaxation in the ECM is crucial, as it influences cellular responses and need to be considered when designing bioinspired materials for many biological applications like cell culture, tissue engineering, and soft robotics. Here, we introduce a collagen-inspired hydrogel with tunable crosslink kinetics. We utilize collagen-mimetic peptides with controlled dissociation rates as dynamic crosslink in star-shaped polyethylene glycol network. We show that extremely slow dissociation rates of the crosslink cause an uncommon relaxation behavior that is reminiscent of soft glassy materials, showing out-of-equilibrium properties. Specifically, subjecting these networks to pre-stress and aging causes compressed exponential relaxation, which has been rarely reported in only a small number of soft material systems. This phenomenon is linked to ultraslow dynamics hindering the release of internal stresses. In such systems, slow crosslink dissociation delays network relaxation until an external trigger is applied. In future work, we aim to investigate the interplay between locally generated stresses, such as cellular traction forces, and network relaxation properties.