Self-Healing Hydrogel with a Double Dynamic Network Comprising Imine and Borate Ester Linkages

Abstract

A self-healing hydrogel enriched with properties from a double-dynamic network (DDN) that has been prepared via two dynamic linkages (imine and borate ester) by using a single polymeric cross-linker. The four-component Ugi reaction was used for easily synthesizing multifunctional poly­(ethylene glycol) (MF-PEG) with a benzaldehyde group and phenylboronic acid group at each end of the chain. This MF-PEG simultaneously cross-linked with poly­(vinyl alcohol) through the borate ester and glycol chitosan via an imine to generate a self-healing hydrogel with a unique DDN structure in seconds under mild conditions (pH ≈ 7, 25 °C). The prepared hydrogel showed enhanced strength and mucoadhesive abilities because of the complimentary interpenetrating dynamic networks. The DDN hydrogel showed satisfying biocompatibility and was further used in an in vivo mouse model. The hydrogel was injected to successfully deliver an antitumor drug and achieved a superior performance compared to traditional delivery methods. To the best of our knowledge, this is the first report of using the Ugi reaction to prepare a DDN self-healing hydrogel. We hereby propose a general strategy for the facile preparation of self-healing materials with improved properties. The strategy also opens a new avenue for synthesizing multifunctional/reinforced materials with the combination of dynamic chemistry and multicomponent reactions.

Transparent Conductive Supramolecular Hydrogels with Stimuli‐Responsive Properties for On‐Demand Dissolvable Diabetic Foot Wound Dressings

“…CD31 immunohistochemistry was applied to observe the neovascularization in regenerated granulation tissue, while Giemsa staining was used to investigate the bacterial colonization in wound tissues. [19,47,48] Statistical Analysis: The data were expressed as means ± standard deviation (SD) from at least three independent experiments, and the statistical analysis was carried out using ANOVA with Tukey's posthoc analysis (SPSS Inc., Chicago, IL). P < 0.05 was considered a statistically significant difference.…”

“…CD31 immunohistochemistry was applied to observe the neovascularization in regenerated granulation tissue, while Giemsa staining was used to investigate the bacterial colonization in wound tissues. [ 19,47,48 ]…”

Dually Crosslinked Polymer Networks Incorporating Dynamic Covalent Bonds

“…In contrast to IPNs, so-called combined networks are constituted of two different network structures that are not necessarily interlaced but are chemically connected. For example, Tao and colleagues used this strategy to design a multi-responsive hydrogel consisting of two different networks crosslinked with dynamic imine and boronic ester moieties [ 51 ]. Using the Ugi reaction, a tetrafunctional poly(ethylene glycol) (PEG) with a benzaldehyde group and phenylboronic acid group at each chain-end was prepared from a dicarboxy-homotelechelic PEG.…”

Antioxidant Polymers via the Kabachnik‐Fields Reaction to Control Cellular Oxidative Stress

“…Examples of such MCRs include the Passerini, Ugi, Biginelli, Hantzsch, Kabachnik–Fields (KF), and Mannich reactions. [ 15–32 ] MCRs are suitable for the preparation of polymer antioxidants for several reasons. Some antioxidative groups such as phenol are compatible with many MCRs and can be easily introduced into polymer chains without losing their antioxidative ability.…”