RETRACTED: Mesoporous polydopamine (MPDA)-based drug delivery system for oral chemo-photothermal combinational therapy of orthotopic colon cancer

Oral nano-drug delivery systems offering combination therapy have garnered significant interest in colon cancer treatment due to their precision in targeting tumors and minimizing peripheral tissue exposure. However, challenges such as the complex gastrointestinal environment and effective retention of nanoparticles in the colon have impeded further advancement. We developed a novel oral drug delivery system designed for localized treatment of colon cancer via chemotherapy and photothermal therapy (PTT). This system utilized mesoporous polydopamine (MPDA) as a photothermal carrier for doxorubicin hydrochloride (DOX), with surface modification using folic acid (FA) to enhance systemic tumor targeting. Additionally, to ensure gastrointestinal retention and precise colon localization, the nanoparticles were coated with an enteric-soluble material, ES100, resulting in the formulation MPDA-FA-DOX/ES100. This formulation exhibited high photothermal conversion efficiency, robust photothermal stability, and responsive drug release under near-infrared (NIR) laser stimulation. FA modification significantly enhanced the cellular uptake of nanoparticles by CT26 cells, promoting greater cytotoxic effects through combined chemotherapy and PTT. In vivo, MPDA-FA-DOX/ES100 demonstrated superior accumulation in colon tumor tissues and substantial photothermal effects, and notably, the CT/PTT group demonstrated significant tumor growth inhibition along with excellent biocompatibility. Collectively, these findings highlight the clinical potential of MPDA-FA-DOX/ES100 as an effective platform for localized and synergistic CT/PTT of colon cancer.