A dry double-sided tape post-treated with tannic acid for long-term adhesion in a wet environment

Medical adhesives have been used for wound closure with many advantages over sutures, but the wet environment in the human body poses a big challenge for its application. The currently used dry double-sided tape (DST) can remove the water barrier by water absorption, but its over-swelling makes it difficult to achieve long-term adhesion. In this study, a dry double-sided tape post-treated with tannic acid (DST-TA) was developed. A double network adhesive composed of polyacrylic acid and gelatin was first prepared by free radical photocrosslinking, and was post-treated in acidic (pH = 2) tannic acid solution. Tannic acid was immobilized in the DST through the catecholyl group, which could form hydrogen bonds with the DST, or react with the amino group on the gelatin by oxidizing to quinone. In vivo and in vitro studies demonstrated that DST-TA had significantly higher swelling resistance and tensile strength than DST. The introduced catecholyl group could reduce over-swelling of the DST, and improve short-term and long-term adhesion in a wet environment. We also demonstrated that the DST-TA had good hemocompatibility, biodegradability, and no cytotoxicity, offering a potential option for long-term medical adhesive in a wet environment.