A tissue adhesive formed by reacting an oxidized cationic polysaccharide containing aldehyde groups and amine groups with a multi-arm amine is described. The oxidized cationic polysaccharide-based polymer tissue adhesive may be useful for medical applications including wound closure, supplementing or replacing sutures or staples in internal surgical procedures such as intestinal anastomosis and vascular anastomosis, ophthalmic procedures, drug delivery, anti-adhesive applications and as a bulking agent to treat urinary incontinence. Additionally, due to the presence of the positively charged amine groups on the oxidized polysaccharide, the polymer tissue adhesive disclosed herein may promote wound healing and blood coagulation, and may possess antimicrobial properties.