ACADEMIC RESEARCH • 學術研究 2022 UMAGAZINE 26 • 澳大新語 61 Organic near-infrared (NIR) molecules are used in many technologies. In recent years, my research team and I have worked with researchers from various institutions to develop an NIR organic nanosponge and a method for loading NIR organic dyes that promise to improve photodynamic cancer therapy and medical imaging. Wide Applications of Organic NIR Molecules NIR light is electromagnetic radiation that has longer wavelengths than visible light and shorter wavelengths than mid-infrared light. When organic NIR molecules are activated, they can absorb, reflect, or emit NIR light. Such materials are widely used in short-range wireless communications, remote temperature sensing, and solar power generation. Moreover, because organic NIR molecules are so tiny, they can easily penetrate our bodies and cells. This makes them useful for cancer diagnosis and medical imaging. One type of NIR organic molecules, known as ‘dyes’, can be used as photosensitisers in photodynamic therapy (PDT) for cancer. In PDT, doctors inject photosensitisers into the patient’s body, wait for them to accumulate in tumour tissue, and then shine a light of a specific wavelength on the areas to be treated to activate the photosensitisers and generate an active form of oxygen that can destroy the cancer cells nearby. In addition, organic NIR dyes are often used as fluorescent markers in the canning of medical images. In the patient’s body, the fluorescent marker accumulates in the target molecules and emits fluorescent light. Some dyes are also used as contrast agents in computed tomography to increase the contrast of the image, giving a clearer picture of the patient’s blood vessels and organ structures. Loading Nanoparticles with NIR Dyes The use of organic NIR dyes in the field of medicine still faces some limitations. First, many dyes are toxic in living organisms or can cause immune reactions, a property known as low biocompatibility. Secondly, most dyes are poorly soluble in water, which means they are hydrophobic and not hydrophilic. One solution is to create organic NIR nanoparticles that are more biocompatible and less hydrophobic and that can carry organic NIR dyes to their targets. However, because the molecular structure of every dye is different, the nanoparticles that carry the dye, known as carriers, often have to be tailor-made and they are time-consuming to produce. In addition, the process of synthesising the nanoparticles and loading them with dyes is complex and demands stringent conditions. Therefore, it is difficult to ensure that different batches of carriers have the same properties in large-scale production with conventional techniques. Our team, therefore, aims to develop a simple method to load multiple types of dyes onto the same nanoparticle. Creating a New Nanosponge Our team has used poly (styrene-alt-maleic acid), or PSMA, to synthesise a NIR organic nanoparticle, which is a nanopolymer that can carry a wide range of organic NIR dyes. We loaded onto the new PSMA nanoparticles ten dyes, some of which are commercially available and were newly synthesised by us. The new dyes include 424 for the production of organic light-emitting diodes, YI-1, YI-3 and YI-8 for the production of organic solar cells, and ADF-1-3 and DTDPTID for the production of dye-sensitised solar cells. The results show that the PSMA nanoparticles can carry more dyes and are less toxic to the cells than conventional carriers. 這張熒光圖像呈現了小鼠體內被裝載了242、YI‐1、ADF1這三種染料的PSMA 納米粒子所標記的癌細胞 This fluorescence image shows cancer cells in mice labelled with PSMA nanoparticles loaded with three dyes: 242, YI-1 and ADF1
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