Cellulose-based bilayer films with asymmetric properties for the sealing of tissue lesions

Abstract To be able to support the complex process of wound closure, a biocompatible material is required that combines suitable adhesiveness and stability with the ability to withstand certain biological challenges such as biofouling while avoiding undesired side effects i.e., hemolysis. Here, we present an asymmetrically designed, cellulose-based bilayer film that satisfies all those requirements and can be produced in a simple and environmentally friendly manner. The wound-facing side of this film features excellent adhesive properties brought about by a biocompatible catechol functionalization of carboxymethyl cellulose and promotes blood coagulation while avoiding hemolysis. In contrast, the outer side of the film has bacteria-repellent properties, which are established by the anti-bacterial glycoprotein mucin, integrated into a fibrous cellulose matrix, that can be covalently crosslinked. In addition, the construct can act as a drug reservoir and decomposes in a wet environment. These properties render the bilayer film a promising candidate for applications in wound closure, particularly for lesions encountered in intestinal or ocular tissues.