Design and Fabrication of a High-Strength Hydrogel with Ideally Homogeneous Network Structure from Tetrahedron-like Macromonomers

TLDR

The authors designed a tetra‑PEG hydrogel by combining two symmetrical tetrahedron‑like macromonomers of identical size. The gel network was defined by the length of the tetrahedral PEG arms, producing a homogeneous structure and high mechanical strength comparable to native articular cartilage, while gelation from mixing two biocompatible macromonomer solutions ensured biocompatibility. The hydrogel exhibited breaking‑strength maxima at the overlap concentration (C*) and at 2C*, with dynamic light scattering revealing near‑absence of network inhomogeneities at C*, confirming that controlling network homogeneity yields a high‑strength hydrogel with potential biomedical applications.

Abstract

As a new class of high-strength hydrogels, we designed a tetra-PEG gel by combining two symmetrical tetrahedron-like macromonomers of the same size. Because the nanostructural unit of the gel network was defined by the length of the tetrahedral PEG arm, the gel had a homogeneous structure and resultant high mechanical strength comparable to that of native articular cartilage. Furthermore, since the gel was formed by mixing two biocompatible macromonomer solutions, the gelation reaction itself and the resultant gel were also biocompatible. The breaking strength had local maxima at the overlap concentration of the macromonomers (C*) and at 2C*. Dynamic light scattering measurement indicated the near absence of inhomogeneities in the network at C*. Thus, we successfully designed and fabricated a high-strength hydrogel by controlling the homogeneity of network structure for the first time, which will lead to multiplied effects, i.e., contributing to the understanding of ideal networks, providing a universal strategy for designing high-strength gels, and opening up the biomedical application of hydrogels.