Mucoadhesive and antifouling Janus polysaccharide film for prevention of colorectal cancer recurrence post‐surgery

Colorectal cancer is one of the most common cancers, and current treatment options include surgery, chemotherapy, and radiation therapy. Most patients undergo surgery, which often requires extensive resection of the colon to prevent recurrence and metastasis of residual malignant tumor cells, leading to postoperative pain and discomfort in daily routines. Although versatile therapeutic patches have been developed to induce tumor apoptosis, achieving both great adhesiveness on the mucus layers of the colon tissue and anti‐cell/tissue adhesion to other surrounding organs remains a challenge. Herein, we report a Janus polysaccharide film comprising two polymers: mussel‐inspired catechol‐conjugated chitosan (Chi‐C) with muco‐adhesiveness, and alginate (Alg) with anti‐adhesion property. The Chi‐C and Alg polymers form a stably entangled bilayer film via electrostatic interactions. The Janus film shows a strong tissue adhesive strength of ∼10 kPa for the Chi‐C layer and weak strength of ∼1 kPa for the Alg layer. Particularly, the Janus film encapsulating an anti‐cancer drug exhibits a directional release profile to the tumor site, which is effective for triggering tumor death in in vivo colorectal tumor resection model. Ultimately, such anti‐cancer material strategies using bilayered structures are promising for advanced tumor therapy. For the patients undergoing the resection surgery of the colon cancer, it is important to minimize the extent of resection and prevent additional infection at the surgical site. Herein, we report a thin Janus film consisting of tissue‐adhesive catechol‐conjugated chitosan and antifouling alginate. The film encapsulating anti‐cancer drugs can inhibit tumor growth when potentially applied onto the surgical site.