Synthesizing Functional Biomacromolecular Wet Adhesives with Typical Gel–Sol Transition and Shear-Thinning Features

Functional wet adhesives have become increasingly important in the field of biomedicine. Herein, modified chitosan (CS) biomacromolecule is synthesized as tissue wet adhesives and hemostatic materials. In a typical case, after getting through two steps of organic reactions, catechol and lysine groups are grafted onto the chitosan backbone, enabling for the successful preparation of one kind of novel biomacromolecule of chitosan-catechol-lysine (CHIC-Lys). The as-prepared CHIC-Lys biomacromolecule shows improved wet adhesion strength, concentration-dependent gel-sol transition feature when shear stress is cycled between low stress (0.2 Pa) and high stress (2 Pa) at room temperature, and obvious shear-thinning feature under wide concentration ranges, along with good biocompatibility, comparable with traditional CS. Based on these obvious characteristics, CHIC-Lys is successfully coated onto the surface of a syringe needle and the decorated needle shows considerable hemostatic effect in a test of rats venous bleeding. Overall, the as-synthesized CHIC-Lys biomacromolecule exhibits considerable application potential in the biomedical field.