Injectable Extracellular Matrix-Inspired Hemostatic Hydrogel Composed of Hyaluronan and Gelatin with Shear-Thinning and Self-Healing.

Injectable ECM-inspired hydrogels composed of hyaluronic acid and gelatin are biocompatible and potentially useful for various medical applications. We developed injectable hydrogels composed of monoaldehyde-modified hyaluronic acid (HA-mCHO) and carbohydrazide-modified gelatin (GL-CDH), "HA/GL gel", whose ratios of HA-mCHO to GL-CDH were different. The hydrogels exhibited gelation times shorter than 3 s.

Tri-branched gels: Rubbery materials with the lowest branching factor approach the ideal elastic limit.

Unlike hard materials such as metals and ceramics, rubbery materials can endure large deformations due to the large conformational degree of freedom of the cross-linked polymer network. However, the effect of the network's branching factor on the ultimate mechanical properties has not yet been clarified. This study shows that tri-branching, which entails the lowest branching factor, results in a large elastic deformation near the theoretical upper bound.

Temperature Dependence of Polymer Network Diffusion.

The swelling dynamics of polymer gels are characterized by the (collective) diffusion coefficient D of the polymer network. Here, we measure the temperature dependence of D of polymer gels with controlled homogeneous network structures using dynamic light scattering. An evaluation of the diffusion coefficient at the gelation point D_{gel} and the increase therein as the gelation proceeds ΔD≡D-D_{gel} indicates that ΔD is a linear function of the absolute temperature with a significantly large negative constant term.

Structure-property relationship of a model network containing solvent.

For the application of polymer gels, it is necessary to control independently and precisely their various physical properties. However, the heterogeneity of polymer gels hinders the precise control over the structure, as well as the verification of theories. To understand the structure-property relationship of polymer gels, many researchers have tried to develop a homogeneous model network.

Three cooperative diffusion coefficients describing dynamics of polymer gels.

Cooperative diffusion coefficient (Dcoop) describes the dynamics of a polymer network in a gel, and is estimated by three independent methods. We measured three Dcoop's of a model polymer network system (Tetra-PEG gels), and obtained the experimental evidence to fundamentally understand the dynamics of polymer gels.