Tumor-Specific Aptamer-Conjugated Polymeric Photosensitizer for Effective Endo-Laparoscopic Photodynamic Therapy

Recent advances in medical technology and endo-laparoscopic devices have enabled the treatment of gastrointestinal (GI) cancers to be minimally invasive through endo-laparoscopic photodynamic therapy (PDT). To achieve an efficient regional or endo-laparoscopic PDT, it is necessary to develop a highly target specific photosensitizer (PS) that can be easily treated to the lesion site with endo-laparoscopic device. Here, an ideal polymeric PS is demonstrated for effective endo-laparoscopic PDT. In the synthetic process, conventional PS (i.e., Chlorin e6, Ce6) is conjugated with an Aptamer (i.e., AS1411) targeting nucleolin (also called C23) overexpressed on the cancer cell membrane using a water-soluble polymeric linker (i.e., polyethylene glycol, PEG). The synthesized Aptamer-PEG-Ce6 could target nucleolin-overexpressing tumor cells efficiently and visualize the tumor tissues through optical and fluorescent imaging both in vitro and ex vivo, and effectively kills cancer cells under laser irradiation. Tumor staining with Aptamer-PEG-Ce6 is easily accomplished through endoscopic equipment within a few minutes. Furthermore, after laser irradiation, Aptamer-PEG-Ce6 is found to penetrate deeply into the tumor tissue and induce apoptosis of tumor cells. Taken together, the tumor-specific Aptamer-conjugated polymeric PS developed in this study has great potential as an ideal photomedicine for effective tumor treatment using endo-laparoscopic PDT.