Development of novel nanoparticles for improved imaging, photo-thermotherapy, drug package, and targeting delivery

M. Wu, J. Chen, X. Li, X. Wu, N. Fahruddin, J.X. Zhao
University of North Dakota, US

Keywords: silica nanowires, hollow silica nanoparticles, graphene quantum dots, imaging, thermotherapy, drug packaging, targeting delivery

Summary:

We first describe the synthesis, characterization, and application of novel silica nanowires (SiNWs) covered with a gold shell of tunable thickness. These Au-modified SiNWs gained strong surface plasmon resonance absorption in the near infrared (NIR) region and showed excellent in vitro biocompatibility and improved photothermal cancer cell killing efficacy at a low laser irradiation density (0.3 W/cm2). Next, we report a method of synthesizing hollow silica nanoparticles through the sol-gel process of tetraethylorthosilicate and polyvinylpyridine-water droplets as soft templates. The spontaneous sol-gel process on the surface of the droplets allowed the formation of a hollow structure. These hollow particles may encapsulate different molecules (polymyxin) in the silica matrix. Finally, we developed a bottom-up method for synthesizing fluorescent graphene quantum dots (GQDs) by one-step pyrolysis of glutamic acid. The GQDs showed strong blue, green and red photoluminescent (PL) under the irradiation of ultra-violet, blue and green light, respectively. The GQDs possess some peroxidase activity and emit NIR fluorescence in the range of 800-850 nm in an excitation dependent manner. The GQDs also showed potential in vivo imaging application in nude mice. These novel nanoparticles may have strong potential for imaging, thermotherapy, drug packaging, and targeting delivery.