A rapid self-healing host-guest supramolecular hydrogel : high mechanical strength and excellent biocompatibility for potential biomedical applications

Abstract

Hydrogels are commonly used in tissue engineering due to their excellent biocompatibility, hydrophilicity, and tissue-like structure. They have shown good support as a primary material in the field of cartilage repair. However, further research and development have revealed some drawbacks and shortcomings of reported hydrogels in terms of mechanical strength and biocompatibility. It was seen that the mechanical behavior of hydrogels was not comparable to that of native tissues. To address the issue, a three-armed host-guest supramolecule (HGSM) was created through covalent cross-linking. This HGSM was then utilized to develop a novel hydrogel that incorporates supramolecular interactions along with covalent interactions into a cross-linked network. It results in a unique structure that enhances the mechanical properties of the hydrogel. The three-armed HGSM was prepared through effective supramolecular host-guest inclusion interactions between isocyanatoethyl acrylate-modified β-cyclodextrin (β-CD-AOI₂) and acryloylated tetra-ethylene glycol-modified adamantane (A-TEG-Ad). The photo-crosslinking reaction was carried out under the photoactive compound ""irgacure"" to form a host-guest (HG) complex, subsequently, the supramolecular hydrogel was formed. The HGSM arms were further complexed with polyvinyl alcohol/chitosan (PVA/CS; PC) to form an interwoven polymeric network (HGSM-PC). It is worth noting that PC-impregnated hydrogels exhibit a wide temperature response range, flexibility, and sensitivity, making them suitable as tissue weight-bearing scaffolds. We found that the HGSM-PC had excellent robustness, fatigue resistance, self-healing properties, and reproducibility due to the covalent cross-linking that maintains its overall shape. This paper outlines the structural features and preparation methods of novel hydrogels that effectively heal and dissipate energy, preventing destructive fracture extension. The hydrogels exhibit higher strength and desired biocompatibility.

Date of Award	2024
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology
Supervisor	Hongkai WU (Supervisor)