Biomimetic Tough Gels with Weak Bonds Unravel the Role of Collagen from Fibril to Suprafibrillar Self‐Assembly

Abstract

Biological tissues rich in type I collagen exhibit specific hierarchical fibrillar structures together with remarkable mechanical toughness. However, the role of collagen alone in their mechanical response at different structural levels is not fully understood. Here, it is proposed to rationalize such challenging interplay from a materials science perspective through the subtle control of this protein self‐assembly in vitro. It is relied on a spray‐processing approach to readily use the collagen phase diagram and set a palette of biomimetic self‐assembled collagen gels in terms of suprafibrillar organization. Their mechanical responses unveil the involvement of mechanisms occurring either at fibrillar or suprafibrillar scales. Noticeably, both modulus at early stage of deformations and tensile toughness probe the suprafibrillar organization, while durability under cyclic loading and stress relaxation reflect mechanisms at the fibril level. By changing the physicochemical environment, the interfibrillar interactions are modified toward more biomimetic mechanical responses. The possibility of making tissue‐like materials with versatile compositions and toughness opens perspectives in tissue engineering.

Mechanical Reinforcement of Lamellar Bilayer Hydrogels by Small Amounts of Co-surfactants

“…All PDGI/PAAm hydrogels exhibited larger hysteresis loop during the first cyclic loading and unloading, followed by smaller loops that are almost overlapped in the later cycles (Figure S14). Such behavior is typical of pure physical hydrogels, 26 confirming that energy dissipation processes mostly originate from breaking of noncovalent interactions, like sacrificial bonds. In order to probe the strength of physical interactions, the same set of experiments was conducted at a high temperature (∼50 °C), above the Krafft point of DGI (43 °C), where bilayers are expected to behave like a liquid crystal.…”

Insights into the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-induced gelation of fully carboxylated collagen and the fabrication of hydrogels with enhanced mechanical properties

“…When the concentration of SCol was increased to 30.0 mg mL À1 , the G 0 value of the SCol(30) hydrogel increased to 310 Pa. The mechanical property of SCol(30) hydrogel is lower than that of previously reported collagen-based materials; 26,27 however, these results indicate that the mechanical properties of the SCol hydrogel are higher than that of the Col hydrogel at the same concentration, and the mechanical properties of the SCol hydrogel could be significantly improved by increasing the concentration of SCol. Furthermore, the mechanical properties of SCol and Col were further explored, and their stress-strain curves and maximum compressive stress are shown in Fig.…”

Anisotropic dense collagen hydrogels with two ranges of porosity to mimic the skeletal muscle extracellular matrix

“…After printing, an extended gelling time was required to obtain a complete collagen fibrillogenesis and suitable mechanical properties. During collagen gelling, two phenomena compete: collagen lateral self-assembling into fibrils (fibrillogenesis) and forming physical crosslinking nodes between collagen molecules to get a hydrogel [35,43]. Fibrillogenesis is strongly impacted by collagen concentration, ionic strength, and pH [44].…”