Abstract: Photodynamic therapy (PDT) emerges as a novel approach to treat tumors utilizing “photosensitizers” and “light”. This method involves exposing the tumor site to specific wavelengths of light, activating photosensitizers concentrated in the tumor to generate highly oxidizing reactive oxygen species, ultimately dismantling the tumor. In comparison to surgery, chemotherapy, and radiation therapy, PDT boasts simplicity in operation, precise targeting, minimal invasiveness, lack of drug resistance, and the ability to trigger systemic immunity. While PDT has gained widespread adoption in developed nations, its promotion in China is still underway, hampered by a lack of public understanding. In response, we present a popular science experiment elucidating tumor-targeted photodynamic therapy using a laboratory-synthesized selenium-Rhodamine photosensitizer. The experiment encompasses enzyme activation of targeted photosensitizers, visual detection of singlet oxygen, and the photodynamic eradication of cancer cells. This experiment vividly illustrates the scientific principles behind targeted photodynamic therapy, enhancing public awareness of photodynamic cancer treatment. Such efforts are crucial for advancing the adoption of photodynamic therapy in our country, underscoring the pivotal role of chemistry in cancer treatment. The entire popular science experiment is straightforward, visually intuitive, and has demonstrated effective results in science outreach.

Key words: Photodynamic therapy, Photosensitizer, Enzyme activation, Singlet oxygen, Visual detection