Sprayable agarose-derived dopamine-grafted microgels for promoting tissue adhesion in skin regeneration

A sprayable wound dressing is convenient, simple and easy to administer by nonmedical personnel in clinical medicine. In this study, agarose was employed for the first time as a spray for wound care. The strong gelling properties and cross-linked network structure of agarose makes it unsuitable for spraying. Furthermore, agarose gel exhibits shrinkage and is resistant to degradation. These features constitute major disadvantages of agarose as a wound dressing. To overcome these problems, we degraded and modified agarose using the 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) oxidation method, prepared degraded carboxylated agarose (Ag-CA) to improve the biodegradability , and developed a microgel structure that is easy to spray. In addition, we grafted dopamine onto Ag-CA (to yield Ag-g-DA) and evaluated its adhesion to cells and wounds. The surface topography , cell adhesion, tissue adhesion and protein release capabilities of the materials were evaluated, and a histological analysis was performed at 1, 2, 3, and 4 weeks. The introduction of carboxyl and catechol functional groups enabled agarose to bind to cells and thereby promote cell adhesion and growth. The wound adhesion and repair due to Ag-CA and Ag-g-DA were superior to those of unmodified agarose. Furthermore, the agarose-derived hydrogels promoted the downregulation of proinflammatory cytokines, suggesting a potential direction for research in skin regeneration and repair.