MSE Seminar - Dr. Jin Xie - Dept. of Chemistry - UGA
Dr. Jin Xie
Department of Chemistry
Rio-Imaging Research Center
The University of Georgia
Monday, October 3, 2016
4:00 p.m. GTMI/Callaway Bldg. Auditorium
Reception at 3:30 p.m. in the GTMI Atrium
Protein Cages and Synthetic Nanoparticles for
Enhanced Photodynamic Therapy
Photodynamic therapy (PDT) is an emerging cancer treatment modality. Despite the intrinsic focal therapy nature, it is desired that photosensitizers can be delivered to tumors with high selectivity and efficiency. Previous efforts have been focused on polymer- or liposome-based nanocarriers, which are often associated with a suboptimal drug loading rate and a large particle size. In the first half of the lecture, I will be presenting our recent work on using ferritin, a protein cage (~12 nm), as a photosensitizer carrier. Ferritin can encapsulate photosensitizers such as zinc hexadecafluorophthalocyanine (ZnF16Pc) at high efficiency and can be modified by either chemical or genetic methods to impart targeting ligands to the surface. In particular, we’ve successfully introduced folic acid, RGD4C, and a FAP targeting scFv, to the surface of ferritins. By using these surface modified ferritins as carriers, we are able to selectively navigate PDT to cancer cells, tumor endothelial cells, and tumor associated fibroblasts in tumors. One intrinsic limitation of PDT is the shallow tissue penetration of light. In the second half of the lecture, I will be talking about X-ray induced PDT, or X-PDT, a technology that is recently developed to address the shallow penetration issue. The key component of the X-PDT technology is an integrated nanosystem called X-ray nanosensitizer, which consists of: 1) a nanoparticle scintillator that converts X-ray photos to visible photons and; 2) photosensitizer whose excitation matches the emission of the scintillator. Upon X-ray irradiation, the nanoscintillator works as a transducer, producing X-ray excited optical luminescence; the visible photons, in turn, activate the photosensitizers, producing reactive oxygen species, most importantly singlet oxygen, or 1O2. We have shown that X-PDT can be activated from beneath thick tissues to efficiently kill cancer cells. More excitingly, our recent research finds that X-PDT is more than a simple derivative of PDT; rather, it is a unique combination of PDT and radiation therapy. The two modalities target different cellular components; the combination overwhelms cellular repairs, leading to synergistic therapy outcomes.
Dr. Xie received a B.S. in Chemistry in 2003 from Nanjing University, China. He came to the United States in 2004 and obtained his Ph.D. in Chemistry from Brown University in 2008 under the supervision of Dr. Shouheng Sun. As a postdoctoral researcher, he joined the Molecular Imaging Program at Stanford (MIPS), where he worked with Dr. Xiaoyuan Chen on developing nanoparticle-based probes for multimodal imaging. In the summer of 2009, he joined the National Institute of Biomedical Imaging and Bioengineering (NIBIB) at the National Institutes of Health (NIH) as a research fellow. He joined the faculty of University of Georgia in 2011. He is currently an assistant professor at the UGA Chemistry Department and he is holding a joint position at the UGA Bio-Imaging Research Center. His research group focuses on exploring nanotechnology facilitated therapy against cancer and other diseases.