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

Lee CM, Lee TK, Kim DI, Kim YR, Kim MK, Jeong HJ, Sohn MH, Lim ST - Int J Nanomedicine (2014)

Bottom Line: In the ex vivo imaging studies, optical signals were observed mostly in the lungs, liver, pancreas, and kidneys.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Chonnam National University, Yeosu, Jeollanam-Do, Republic of Korea.

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.

No MeSH data available.


Related in: MedlinePlus

TEM images of (A) RITC-SiNPs20(+) and RITC-SiNPs20(−), (B) RITC-SiNPs100(+), and RITC-SiNPs100(−) for determining their in vitro stability in distilled water and HCl solution (pH 1.2). The TEM images of RITC-SiNPs were obtained at 6 hours after immersion in distilled water and HCl solution (pH 1.2) at 37°C.Note: Scale bar =200 nm.Abbreviations: DW, distilled water; RITC-SiNP, rhodamine B isothiocyanate-incorporated silica oxide nanoparticle; RITC-SiNPs20(+), 20 nm positively charged RITC-SiNPs; RITC-SiNPs20(−), 20 nm negatively charged RITC-SiNPs; RITC-SiNPs100(+), 100 nm positively charged RITC-SiNPs; RITC-SiNPs100(−), 100 nm negatively charged RITC-SiNPs; TEM, transmission electron microscopy; sol, solution.
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f3-ijn-9-243: TEM images of (A) RITC-SiNPs20(+) and RITC-SiNPs20(−), (B) RITC-SiNPs100(+), and RITC-SiNPs100(−) for determining their in vitro stability in distilled water and HCl solution (pH 1.2). The TEM images of RITC-SiNPs were obtained at 6 hours after immersion in distilled water and HCl solution (pH 1.2) at 37°C.Note: Scale bar =200 nm.Abbreviations: DW, distilled water; RITC-SiNP, rhodamine B isothiocyanate-incorporated silica oxide nanoparticle; RITC-SiNPs20(+), 20 nm positively charged RITC-SiNPs; RITC-SiNPs20(−), 20 nm negatively charged RITC-SiNPs; RITC-SiNPs100(+), 100 nm positively charged RITC-SiNPs; RITC-SiNPs100(−), 100 nm negatively charged RITC-SiNPs; TEM, transmission electron microscopy; sol, solution.

Mentions: All RITC-SiNPs had a uniform spherical shape (Figure 1). The zeta potential values of RITC-SiNPs20(+), RITC-SiNPs20(−), RITC-SiNPs100(+), and RITC-SiNPs100(−) were 37.3, −13.4, 32.5, and −43.5 mV, respectively (Figure 2). All RITC-SiNPs showed excitation wavelength (λex) of 543 nm and emission wavelength (λem) of 580 nm. As shown in Figure 3, all RITC-SiNPs had a similar shape and particle size after incubation in the HCl solution at 37°C. A small amount (2%–4% of the total RITC fluorescence activity) of RITC was released from the 20 nm RITC-SiNPs during incubation in the HCl solution (pH 1.2), whereas release and dissociation of free RITC from the 100 nm RITC-SiNPs and the degradation of RITC were not observed (Figure 4).


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

Lee CM, Lee TK, Kim DI, Kim YR, Kim MK, Jeong HJ, Sohn MH, Lim ST - Int J Nanomedicine (2014)

TEM images of (A) RITC-SiNPs20(+) and RITC-SiNPs20(−), (B) RITC-SiNPs100(+), and RITC-SiNPs100(−) for determining their in vitro stability in distilled water and HCl solution (pH 1.2). The TEM images of RITC-SiNPs were obtained at 6 hours after immersion in distilled water and HCl solution (pH 1.2) at 37°C.Note: Scale bar =200 nm.Abbreviations: DW, distilled water; RITC-SiNP, rhodamine B isothiocyanate-incorporated silica oxide nanoparticle; RITC-SiNPs20(+), 20 nm positively charged RITC-SiNPs; RITC-SiNPs20(−), 20 nm negatively charged RITC-SiNPs; RITC-SiNPs100(+), 100 nm positively charged RITC-SiNPs; RITC-SiNPs100(−), 100 nm negatively charged RITC-SiNPs; TEM, transmission electron microscopy; sol, solution.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4279756&req=5

f3-ijn-9-243: TEM images of (A) RITC-SiNPs20(+) and RITC-SiNPs20(−), (B) RITC-SiNPs100(+), and RITC-SiNPs100(−) for determining their in vitro stability in distilled water and HCl solution (pH 1.2). The TEM images of RITC-SiNPs were obtained at 6 hours after immersion in distilled water and HCl solution (pH 1.2) at 37°C.Note: Scale bar =200 nm.Abbreviations: DW, distilled water; RITC-SiNP, rhodamine B isothiocyanate-incorporated silica oxide nanoparticle; RITC-SiNPs20(+), 20 nm positively charged RITC-SiNPs; RITC-SiNPs20(−), 20 nm negatively charged RITC-SiNPs; RITC-SiNPs100(+), 100 nm positively charged RITC-SiNPs; RITC-SiNPs100(−), 100 nm negatively charged RITC-SiNPs; TEM, transmission electron microscopy; sol, solution.
Mentions: All RITC-SiNPs had a uniform spherical shape (Figure 1). The zeta potential values of RITC-SiNPs20(+), RITC-SiNPs20(−), RITC-SiNPs100(+), and RITC-SiNPs100(−) were 37.3, −13.4, 32.5, and −43.5 mV, respectively (Figure 2). All RITC-SiNPs showed excitation wavelength (λex) of 543 nm and emission wavelength (λem) of 580 nm. As shown in Figure 3, all RITC-SiNPs had a similar shape and particle size after incubation in the HCl solution at 37°C. A small amount (2%–4% of the total RITC fluorescence activity) of RITC was released from the 20 nm RITC-SiNPs during incubation in the HCl solution (pH 1.2), whereas release and dissociation of free RITC from the 100 nm RITC-SiNPs and the degradation of RITC were not observed (Figure 4).

Bottom Line: In the ex vivo imaging studies, optical signals were observed mostly in the lungs, liver, pancreas, and kidneys.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Chonnam National University, Yeosu, Jeollanam-Do, Republic of Korea.

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.

No MeSH data available.


Related in: MedlinePlus