Synthesis of a novel nanobioconjugate for targeted photodynamic therapy of colon cancer enhanced with cannabidiol

Abstract

Photodynamic therapy (PDT) is a promising primary treatment option for colorectal cancer (CRC), however CRC is accelerated by resilient CRC stem-like cells, which decrease its efficacy. In recent years, researchers have shown an emerging interest in the anticancer stem cell effects of cannabidiol (CBD). This study developed a targeted nanobioconjugate for specific ZnPcS4 photosensitizer intracellular accumulation within in vitro cultured human CRC cells (CaCo-2) for enhanced PDT primary treatment, as well as limited its secondary spread by combining this treatment with CBD. The final nanobioconjugate (FNBC) was successfully synthesized and characterized using various methods. The cytotoxicity of the FNBC and CBD were tested on CRC cells using laser irradiation at 673 nm with a fluency of 10 J/cm². 24 h post treatment, morphological changes were assessed via microscopy, cell viability was measured using Annexin V-FITC and cellular nuclear DNA was visualized under fluorescent microscopy, following Hoechst staining. FNBC and CBD combinative treatment induced the most significant photodamage, leaving a staggering 6%^*** viable cells. Overall, through active targeting of CRC cells using the FNBC, the enhanced PDT primary treatment of CRC was achieved, and the combinative treatment with CBD noted significant limitations on its secondary spread.