Advances in Metal-based Nanotechnology-based Optical Therapy for the Targeted Treatment of Colorectal Cancer

Colorectal cancer (CRC) is one of the most prevalent gastrointestinal malignancies in the world. To overcome clinical challenges, such as high postoperative recurrence rates and prominent resistance to chemotherapy, new therapeutic strategies are urgently needed. Phototherapy, particularly Photodynamic Therapy (PDT) and Photothermal Therapy (PTT), has unique advantages in selectively killing tumor cells. However, traditional Photosensitizers (PSs) and Photothermal Agents (PTAs) have inherent defects, such as limited tissue penetration depth, poor optical stability, and insufficient targeting ability, which severely restrict phototherapy in clinical applications. Significant advancements have been made in enhancing the phototherapeutic effects of metal nanomaterials in recent years. This progress can be attributed to their tunable optical properties, exceptional Photothermal Conversion Efficiency (PCE), and unique Surface Plasmon Resonance (SPR) effects. In this review, we systematically summarized the latest progress in research on the use of metal nanomaterials for the optical diagnosis and treatment of colorectal cancer. We focused on the mechanism by which typical nanomaterials such as gold, silver, and platinum enhance the therapeutic effect of PDT/PTT. Additionally, a comprehensive analysis was conducted to evaluate the application and potential of nano-optical sensitizers incorporating metallic cores such as gold, silver, iridium, platinum, iron, zinc, copper, ruthenium, and titanium for the diagnosis and treatment of Colorectal Cancer (CRC). This review may provide theoretical guidance for developing new-generation optical diagnostic and therapeutic strategies for treating colorectal cancer.