Transglutaminase-triggered dual gradients of mechanical and biochemical cues self-assembling peptide hydrogel for...

The mechanical properties and bioactive motif densities of extracellular matrix materials play crucial roles in regulating cell behaviors, such as cell adhesion, migration, proliferation, and differentiation. However, current studies on cellular responses to ECM predominantly concentrated on polymer hydrogels featuring a single factor, such as the mechanical strength, the types of bioactive motifs, and the morphology of the polymers. This limited focus may overlook the complex interplay of multiple factors. Here, we developed dual gradient peptide Q₃GT-I₃K hydrogels with tunable mechanical strength (0.3-4.0 kPa) and different density of bioactive motif (0.45-3.67 mM) by enzymatic crosslinking. These hydrogels can mimic the viscoelasticity of natural soft tissues. The properties of mechanical strength and cell responsive motif density could be controlled by modulating the proportion of the substrates in the enzymatic reaction. MC3T3 cells significantly differentiated into osteoblasts after seeded on the Q₃GT-I₃K hydrogel (2.8 kPa, 1.83 mM Q₃GT) for 21 days, identifying from the elevated expression of alkaline phosphatase and substantial calcium nodule formation. Importantly, the engineered hydrogels exert a synergistic effect on the cell behaviors such as early adhesion, late proliferation, and differentiation of MC3T3-E1 cells. This paper introduces a new strategy for designing tissue engineering scaffold materials with specific functions.