Crosslinking dextran electrospun nanofibers via borate chemistry: Proof of concept for wound patches

Dextran-based formulations represent promising candidates for the fabrication of biocompatible scaffolds in tissue engineering or as vehicles for drug delivery. Previous investigations showed that, on its own, dextran is able to promote wound healing in vivo in rat models. Its inherent solubility in water, however, must be overcome by inserting inter-molecular junctions via the use of cross-linkers. While conventional cross-linking methods tend to utilize toxic compounds, such as glutaraldehyde, we demonstrate that simple mixtures of dextran and boric acid, in aqueous solutions, can be electrospun to obtain membranes with controlled degradation times. Boric acid covalently links to the hydroxyls moieties present in the dextran chains yielding boronate ester bridges between dextran chains. Variation in the cross-linking density enhanced the average drug release time up to 500% compared to pristine dextran electrospun scaffolds.