Jin Xie
The University of Georgia, USA
Title: Surface modified ferritin nanoparticles for imaging and drug delivery
Biography
Biography: Jin Xie
Abstract
Ferritins are a family of iron storage proteins with ubiquitous distribution among almost all life forms. Ferritins feature a cage-like structure, with an outer diameter of approximately 12 nm and an inner cavity of 7−8 nm. While natural ferritins are always filled with a ferric oxohydroxy core, artificially made ferritins have an empty cavity at the center. Ferritins are decomposed into the 24 subunits when the pH is decreased to 2~3; when the pH is tuned back to neutral, however, the subunits can reconstitute into a nanocage, and in a nearly intact fashion. Such pH-mediated disassembly-and-reassembly provides a facile means to load molecules into ferritins. For instance, we recently reported that chemotherapeutics like doxorubicin can be into ferritins with high efficiency. Moreover, we found that ZnF16Pc, a potent photosensitizer, can be loaded into ferritins by up to 60wt%. Meanwhile, the surface of ferritins can be modified, through either chemical conjugation or genetic engineering, to present tumor targeting ligands. These features of ferritins, along with their intrinsic biocompatibility and biodegradability, suggest great potential of the platform as a novel delivery system. More recently, we found that ZnF16Pc-loaded and RGD4C presenting ferritins can home to tumor endothelium; with photo-irradiation at relatively low fluences, the resulting PDT treatment leads permeabilized tumor vasculatures. As a result, macromolecules or nanoparticles administered afterwards are able to extravasate and accumulate more efficiently at the tumor sites. This methodology can artificially enhance the EPR effect of tumors so as to improve nanoparticle delivery to tumors