Photo-responsive self-expanding catheter with photosensitizer-integrated silicone-covered membrane for minimally invasive local therapy in malignant esophageal cancer

Photodynamic therapy (PDT) using photosensitizer (PS)-integrated covered self-expandable metallic stents (SEMS) is proposed a new therapeutic approach for the treatment of palliative malignancies; however, the currently hydrophobic PS reduces the photoreactive effect, which leads to aggregation with low water solubility. In here, an aluminum (III)-phthalocyanine chloride tetrasulfonic acid (Al-PcS4)-integrated silicone-covered self-expanding catheter was successfully fabricated to perform localized PDT. The ratio of MeOH and Al-PcS4 concentrations was optimized to achieve PS coating uniformity. The photodynamic activity of the Al-PcS4-integrated silicone membrane was evaluated through laser exposure on membrane-layered tumor cell lines, tumor xenograft-bearing mice. PDT with the Al-PcS4-integrated membrane successfully generated sufficient cytotoxic singlet oxygen, inducing cell death in the esophageal cancer cell lines. PDT-treated tumor xenograft-bearing mice undergo apoptotic cell death and showed significant tumor regression. Localized PDT using an Al-PcS4-integrated silicone-covered self-expanding catheter was technically successful in the rabbit esophagus without severe complications. Based on the endoscopy, esophagography, histology, and immunohistochemistry, our study verified that localized PDT using the Al-PcS4-integrated silicone-covered self-expanding catheter was effective and safe to evenly induce tissue damage. Al-PcS4-integrated silicone-covered self-expanding catheter has substantial potential for the minimally invasive local therapy in malignant esophageal cancer.