Responsive laminarin-boronic acid self-healing hydrogels for biomedical applications

The precise chemical modification of marine-derived biopolymers provides a unique opportunity for fabricating a toolbox of bioactive (bio)materials with modulated physicochemical and biological properties. Herein, the beta-glucan laminarin was functionalized with phenylboronic acid (PBA) moieties that impart chemical reactivity toward diol-containing polymers via boronate esterification. The modification, which involved a two-pot reaction, was successfully confirmed by nuclear magnetic resonance spectroscopy. The resultant biopolymer readily established boronate ester-crosslinked hydrogels with poly(vinyl alcohol) (PVA) within seconds under physiological conditions. These hydrogels exhibited improved rheological properties, which were easily tunable, and revealed a rapid self-healing behavior upon rupture. Moreover, boronate ester bonds enabled the fabrication of reactive oxygen species-responsive and shear-thinning gels that can be administered in situ and respond to the oxidation state of the surrounding microenvironment. Importantly, due to the catalyst-free and mild-crosslinking conditions, the generated laminarin-PBA/PVA hydrogels did not show toxicity upon direct contact with preosteoblasts for up to 48 h, and thus constitute a promising platform for tissue engineering and drug delivery applications.