| Summary: | 博士 === 國立成功大學 === 化學系 === 106 === In recent years, various nanoparticles have been developed for application in biomedicine. How to deliver nanoparticles to the affected area then trigger the therapy and reduce the side effect have become a big issue. Among the triggering methods, light-triggering is a more convenient way. What you need is a light source like laser or infrared treatment instrument, then you can perform treatment or drug release. You don’t need expensive and huge facilities. On the other hand, light-triggering is a non-invasive therapy method. Compared to traditional surgery, the pain that patients suffered from can be drastically reduced. We can also focus the therapy area at wherever we want to reduce side effect. In this research, we developed three different kinds of nanoparticles for photothermal therapy, light-triggered drug release, and photodynamic therapy. The followings are the introductions.
In chapter 2, we introduced the fabrication of carbon-iron oxide nanocomposite. The carbon shell has photothermal effect. With irradiation of laser, it can produce heat for photothermal therapy. Moreover, the iron oxide encapsulated inside can serve as magnetically targeting and magnetic resonance imaging. The unique yolk-shell structure enables us to utilize the cavity for encapsulating low boiling point liquid PFH. Under photothermal effect, it will vaporize and produce bubble for the use in ultrasound imaging. In our experimental design, we guided our particles by magnet to the tumor site, and find the most accumulation time point by MRI. Later, laser was irradiated on the tumor site for photothermal therapy. At the same time, the enhanced ultrasound image was also observed. This design not only has the merit of light-triggering therapy, but also have targeting ability and multifunctional imaging, which have potential use in clinical biomedical applications.
In chapter 3, we want to use the advantage of light-triggered drug release to study the optimized therapy for cancer cells of anti-cancer drug” methotrexate” (MTX) by control the time point of drug release. We modified a photocleavable molecule and then the drug on the surface of upconversion nanoparticles. Upon irradiation of 980 nm laser, this kind of nanoparticle will emit light in UV region, which will cleave photocleavable molecule and then the drug will be released. In previous research, people showed that there are two pathways for uptake of MTX in HeLa cells. One is reduced folate carrier and another is folate receptor. If we deliver pure drug, reduced folate carrier will be a better choice. However, the research using nanoparticles as carrier deliver drug always by folate receptor. It is interesting to use our photo-triggering drug delivery system to study these two pathways. We incubated the HeLa cell with our material, and released the drug extracellularly and intracellularly to compared the cytotoxicity of cancer cell. The results showed that intracellularly delivery seems to be a better choice.
In chapter 4, we used the different surface property of Janus nanoparticles to modify ROS generator and ROS sensor, making the Janus nanoparticle have self-sensing function. In nanomedicine, ROS is used for photodynamic therapy. With the irradiation of 633 nm laser, the TBO on surface of Janus nanoparticle can generate ROS. Our research demonstrate that this generated ROS has ability to kill cancer cell. Besides, the generated ROS from TBO can be detected by APF modified on the other side of Janus nanoparticles. Upon receiving ROS, APF will release strong fluorescence species. This result can be proved by fluorescence spectra. The system we developed not only can be applied in photodynamic therapy, but also have potential application in bio-imaging study.
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