Antibacterial Self-Healing Hydrogel via the Ugi Reaction

Multifunctional hydrogels are typically constructed from multifunctional polymers that are synthesized through tedious multistep processes. Here, a multifunctional poly(ethylene glycol) (MF-PEG) containing phenylboronic acid and phenolic groups at the poly(ethylene glycol) ends was prepared via the one step Ugi reaction, which greatly simplified the preparation of this multifunctional polymer. The resulting MF-PEG can cross-link poly(vinyl alcohol) via dynamic borate ester linkages to quickly generate a self-healing hydrogel under mild conditions (∼10 s, pH ∼ 7.4, 25 °C). This self-healing hydrogel displayed antibacterial properties because of the presence of phenolic groups in the MF-PEG units. The antibacterial capability of this hydrogel was similar to 50 times the minimum inhibitory concentration (MIC) of a penicillin–streptomycin combination antibiotic to Escherichia coli and 10 times the MIC to Staphylococcus aureus. This research demonstrated an application of the multicomponent reactions in interdisciplinary fields. It might have important implications to the polymer chemistry and material science communities.