Chitooligosaccharide endowed tunable adhesion to self-gelling powders for rapid hemostasis and sutureless skin wound closure.

Self-gelling powders have recently emerged as promising tissue adhesives for bleeding wound care. However, to simultaneously achieve strong tissue adhesion and on-demand removal without debridement remains a significant challenge. Here, we developed an ultrafast self-gelling powder compositing of acrylic acid/2-aminoethyl methacrylate copolymers (AMA) and chitooligosaccharide (COS). Upon absorbing water/blood from wet tissue surfaces, AMA-COS powders could quickly transform into an integral hydrogel that firmly adhered to tissues (adhesion strength up to 37.74 kPa) based on strong electrostatic interactions, achieving tight wound sealing. Following exposure to COS solutions, the hydrogel exhibited a significant reduction in adhesion strength (3.28 kPa), allowing for easy removal of the adhesive from tissue surfaces. Moreover, the AMA-COS powders could enable effective hemostasis (within 20 s) of acute tail, liver, and stomach bleeding on rats. In vivo studies further validated that the AMA-COS powder-based adhesive could enable rapid & robust adhesion and on-demand removal for sutureless skin incision closure and tissue healing, outperforming surgical sutures and commercial cyanoacrylate glue. These features make AMA-COS powder adhesive to be a promising hemostatic sealant for rapid bleeding control and non-invasive wound closure & tissue repair. STATEMENT OF SIGNIFICANCE: Self-gelling powders have recently emerged as promising tissue adhesives for bleeding wound care. However, achieving reliable tissue adhesion while enabling on-demand removal without debridement remains a significant challenge. This work developed a new type of ultrafast self-gelling powder (AMA-COS) with tunable tissue adhesion on varying complexation with chitooligosaccharide (COS) for rapid hemostasis and sutureless skin wound closure. The AMA-COS powders can quickly gel and firmly adhere to tissue surfaces upon water/blood absorption, forming tight wound sealing, while it is able to easily detach from tissue merely by exposure to additional COS solutions. We believe the AMA-COS powder could be a high-efficiency multi-functional fault-tolerant bioadhesive for rapid bleeding control and non-invasive wound closure and tissue repair.