Optical imaging of absorption and distribution of RITC-SiO2 nanoparticles after oral administration

Abstract

Purpose In this study, we investigated the absorption and distribution of rhodamine B isothiocyanate (RITC)-incorporated silica oxide nanoparticles(SiNPs) (RITC-SiNPs) after oral exposure, by conducting optical imaging, with a focus on tracking the movement of RITC-SiNPs of different particle size and surface charge. Methods RITC-SiNPs (20 or 100 nm; positively or negatively charged) were used to avoid the dissociation of a fluorescent dye from nanoparticles via spontaneous or enzyme-catalyzed reactions in vivo. The changes in the nanoparticle sizes and shapes were investigated in an HCl solution for 6 hours. RITC-SiNPs were orally administered to healthy nude mice at a dose of 100 mg/kg. Optical imaging studies were performed at 2, 4, and 6 hours after oral administration. The mice were sacrificed at 2, 4, 6, and 10 hours post-administration, and ex vivo imaging studies were performed. Results The RITC-SiNPs were stable in the HCl solution for 6 hours, without dissociation of RITC from the nanoparticles and without changes in size and shape. RITC-SiNPs flowed into the small intestine from the stomach and gradually moved along the gut during the experiment. In the ex vivo imaging studies, optical signals were observed mostly in the lungs, liver, pancreas, and kidneys. The orally administered RITC-SiNPs, which were absorbed in the systemic circulation, were eliminated from the body into the urine. The 20 nm RITC-SiNPs showed higher uptake in the lungs than the 100 nm RITC-SiNPs. The distribution of the 100 nm RITC-SiNPs in the liver was higher than that of the 20 nm RITC-SiNPs, but the differences in the surface charge behavior were imperceptible. Conclusion We demonstrated that the movement of RITC-SiNPs after oral exposure could be traced by optical imaging. Optical imaging has the potential to provide valuable information that will help in understanding the behavior of SiNPs in the body following exposure.

Feasibility Study of the Permeability and Uptake of Mesoporous Silica Nanoparticles across the Blood-Brain Barrier

“…The detection was based on a fluorescent marker; the authors did not acknowledge potential nanoparticle degradation issues. In [ 35 ], silica nanoparticles were not found in the brain of rats within 90 days after oral and dermal administration; a similar study conducted on mice, did not find silica nanoparticles the brain within 10 hours after oral exposure [ 36 ]. In [ 37 ], magnetic nanoparticles overcoated with silica were detected in the brain after intraperitoneal administration.…”

Photoacoustic staging of nodal metastases using SPIOs: Comparison between in vivo, in toto and ex vivo imaging in a rat model

“…These characteristics are already being exploited for breast cancer detection [9,16,23], melanoma imaging [12,18] and tumor visualization in small animals [24,46]. In addition, the potential of silica-coated super paramagnetic iron oxide nanoparticles has been demonstrated in ex vivo muscular tissue [4] and multiple studies have shown the potential of various nanoparticle dispersions for photoacoustic enhancement [17,25,26].…”