Strong Bioinspired Polymer Hydrogel with Tunable Stiffness and Toughness for Mimicking the Extracellular Matrix

Functional mechanical attributes of natural and synthetic gel-based scaffolds in tissue engineering: strain-stiffening effects on apparent elastic modulus and compressive toughness

The accurate identification and determination of elastic modulus and toughness, as well as other functional mechanical attributes of artificial tissues, are of paramount importance in several fields of tissue science, tissue engineering and technology, since biomechanical and biophysical behavior is strongly linked to biological features of the medical implants and tissue-engineering scaffolds. When soft or ultra-soft materials are investigated, a relevant dispersion of elastic modulus values can be achieved, due to the strain-stiffening effects, inducing a typical non-linear behavior of these materials, as a function of strain-range. In this short communication, the Apparent elastic modulus strain-range dependence is estimated from a segmentation of the strain stiffening curve, and the related compressive toughness is investigated and discussed, based on experimental evidence, for 6 different kinds of gels, used for artificial tissue fabrication; experimental results are compared to mechanical properties of native human tissues.

Photo-tunable hydrogel mechanical heterogeneity informed by predictive transport kinetics model

Understanding the three-dimensional (3D) mechanical and chemical properties of distinctly different, adjacent biological tissues is crucial to mimicking their complex properties with materials. 3D printing is a technique often employed to spatially control the distribution of the biomaterials, such as hydrogels, of interest, but it is difficult to print both mechanically robust (high modulus and toughness) and biocompatible (low modulus) hydrogels in a single structure. Moreover, due to the fast diffusion of mobile species during printing and nonequilibrium swelling conditions of low-solids-content hydrogels, it is challenging to form the high-fidelity structures required to mimic tissues. Here a predictive transport and swelling model is presented to model these effects and then is used to compensate for these effects during printing. This model is validated experimentally by photopatterning spatially distinct hydrogel elastic moduli using a single photo-tunable poly(ethylene glycol) (PEG) pre-polymer solution by sequentially patterning and in-diffusing fresh pre-polymer for further polymerization.

A biomimetic hierarchical structure with a hydrophilic surface and a hydrophobic subsurface constructed from waterborne polyurethanes containing a self-assembling peptide extender

A biomimetic hierarchical structure with a hydrophilic surface and a hydrophobic subsurface is constructed from waterborne polyurethanes.

Simultaneous superior lubrication and high load bearing by the dynamic weak interaction of a lubricant with mechanically strong bilayer porous hydrogels

Dynamic weak interaction of a lubricant with mechanically strong bilayer porous hydrogels exhibits simultaneous superior lubrication and high load bearing.