Multifunctional Core–Shell Silica Nanoparticles for Highly Sensitive 19F Magnetic Resonance Imaging†
This research was supported by the Ministry of Education, Culture, Sports, Science, and Technology (Japan) (grant numbers 24108724, 24685028, 24115513, 24651259, 25620133, and 25220207), by the Japanese Society for the Promotion of Science (JSPS) through its Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST Program), and by CREST from JST. The authors acknowledge the Asahi Glass Foundation and the Magnetic Health Science Foundation. The authors thank Prof. Tsutomu Ono (Okayama University) for helpful discussion to synthesize nanomaterials, and Dr. Takayuki Kato and Dr. Takao Sakata (Osaka University) for their support in TEM measurements. Some of the experiments were carried out at the Research Center for Ultra-High Voltage Electron Microscopy, Osaka University. The authors also thank Dr. Yuko Kamikawa (Osaka University) for the valuable discussion.
Graphical Abstract
Highly sensitive 19F magnetic resonance imaging (MRI) is a useful method for in vivo imaging without background signals. However, the low sensitivity of 19F MRI limits its practical application. Novel multifunctional nanoparticles for highly sensitive 19F MRI are reported, which consist of a liquid perfluorocarbon core and a silica shell (see picture).
Abstract
19F magnetic resonance imaging (19F MRI) is useful for monitoring particular signals from biological samples, cells, and target tissues, because background signals are missing in animal bodies. Therefore, highly sensitive 19F MRI contrast agents are in great demand for their practical applications. However, we have faced the following challenges: 1) increasing the number of fluorine atoms decreases the solubility of the molecular probes, and 2) the restriction of the molecular mobility attenuates the 19F MRI signals. Herein, we developed novel multifunctional core–shell nanoparticles to solve these issues. They are composed of a core micelle filled with liquid perfluorocarbon and a robust silica shell. These core–shell nanoparticles have superior properties such as high sensitivity, modifiability of the surface, biocompatibility, and sufficient in vivo stability. By the adequate surface modifications, gene expression in living cells and tumor tissue in living mice were successfully detected by 19F MRI.
