While natural systems have evolved elegant self-assembled materials, the recreation of such materials in a synthetic system remains a challenge. Looking towards the native extracellular matrix, we can see the power of self-assembly, yet also see that the marriage of supramolecular assembly and covalent bond formation is a popular motif for enhanced mechanical properties. However, supramolecular materials utilized for tissue engineering often suffer from poor mechanical properties and poor fabrication performance. In order to address these challenges, we set out to create supramolecular hydrogels from 1,3,5-benzenetricarboxamide which could then be covalently reinforced. By utilizing a novel desymmetrization strategy developed in our lab, we could quickly create macro(supra)molecular monomers with synthetically addressable side groups. These supramolecular architectures underwent self-assembly in PBS, creating long, 1D assemblies as seen by cryo-EM; at higher concentrations, they also formed dynamic hydrogels. These supramolecular structures could be covalently captured, and maintaining their shape and physical properties. Impressively, upon covalent capture, these materials became surprisingly tough with over 120 kJ/m<sup>3</sup> toughness at a compressive modulus of 80 kPa; similar to native cartilage tissue. Due to their self-healing and injectable nature, these materials were amenable to 3D bioprinting, and could be utilized to create complex architectures like a human sized meniscus. Furthermore, these materials were shown to be highly cytocompatible, could be rendered biodegradable via the incorporation of MMP linkers, and are currently under investigation for cartilage tissue formation. Via careful supramolecular design, the cooperative effect of covalent reinforcement can lead to highly processable and biomimetic architectures interesting for tissue engineering.

Leveraging 1D supramolecular polymers to create tough biomimetic hydrogels for biomedical applications

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.