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Tegafaw, Tirusew,Oh, In Taek,Cha, Hyunsil,Yue, Huan,Miao, Xu,Ho, Son Long,Ahmad, Mohammad Yaseen,Marasini, Shanti,Ghazanfari, Adibehalsadat,Kim, Hee-Kyung,Chae, Kwon Seok,Chang, Yongmin,Lee, Gang Ho Elsevier 2018 The Journal of physics and chemistry of solids Vol.120 No.-
<P><B>Abstract</B></P> <P>In this study, amorphous carbon nanoparticles (CNPs) with an average diameter of 2.2 nm were synthesized by reducing dextrose (C<SUB>6</SUB>H<SUB>12</SUB>O<SUB>6</SUB>) with sodium hydroxide in an aqueous medium. The amorphous CNPs formed stable colloidal suspensions in water owing to the presence of hydrophilic functional groups on the nanoparticle surfaces. The amorphous CNPs exhibited ultraviolet (UV)-visible absorption (λ<SUB>abs</SUB>) at 267 nm and emission (λ<SUB>em</SUB>) at 453 nm under UV irradiation; thus, the colloidal suspension appeared sky-blue in color under UV irradiation. The amorphous CNPs were paramagnetic with weak magnetization at room temperature and exhibited small longitudinal (r<SUB>1</SUB>) and transverse (r<SUB>2</SUB>) water proton relaxivities of 0.036 and 0.068 s<SUP>−1</SUP>mM<SUP>−1</SUP>, respectively. The amorphous CNPs exhibited no cellular toxicity up to the measured carbon concentration of 500 μM and presented fluorescence microscopy images on a micrometer scale, thus demonstrating their utility in fluorescence bio-imaging applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The amorphous CNPs with an average diameter of 2.2 nm were synthesized in an aqueous medium. </LI> <LI> The CNPs were non-toxic and formed stable colloidal suspensions in water. </LI> <LI> The CNPs were paramagnetic and exhibited weak magnetization at room temperature. </LI> <LI> The CNPs exhibited small water proton relaxivities. </LI> <LI> Fluorescence microscopy demonstrated the utility of the CNPs in fluorescence bio-imaging applications. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Tegafaw, Tirusew,Bony, Bardul Alam,Xu, Wenlong,Cha, Hyunsil,Chang, Yongmin,Lee, Sang-Hyup,Chae, Kwon Seok,Lee, Gang Ho American Scientific Publishers 2017 Journal of Nanoscience and Nanotechnology Vol.17 No.4
<P>Mixed Zn(II)/Gd(III) oxide nanoparticles (similar to 8 mole% Zn) with d(avg) of 2.1 nm were synthesized. The D-glucuronic acid coated Zn(II)/Gd(III) oxide nanoparticles showed a longitudinal water proton relaxivity (r(1)) of 12.3 s(-1)mM(-1) with r(2)/r(1) = 1.1, corresponding to an ideal condition for T-1 MRI contrast agent. We attribute this to reduced magnetization of the mixed nanoparticles owing to non-magnetic Zn in the nanoparticles. Their effectiveness as a T-1 MRI contrast agent was confirmed by acquiring in vivo T-1 MR images of a mouse after intravenous injection.</P>
Tegafaw, Tirusew,Xu, Wenlong,Ahmad, Md. Wasi,Xu, Miao,Chang, Yongmin,Chae, Kwon Seok,Kim, Tae Jeong,Lee, Gang Ho American Scientific Publishers 2016 Journal of Nanoscience and Nanotechnology Vol.16 No.10
<P>Nearly monodisperse Fe3O4 nanoparticles (d(avg) = 20 +/- 1 nm) were synthesized in an aqueous phase under an argon flow, and then coated with fluorescent brightener (FB) 28. The Fe3O4 nanoparticles were superparamagnetic, with large saturation magnetizations of 54.1 emu/g at 5 K and 48.5 emu/g at 300 K. The FB-28-coated Fe3O4 nanoparticles showed a strong fluorescence maximum (lambda(max)) at 435 nm, and also gave strongly fluorescent confocal images in both the green and blue regions, because of the FB 28 coated on the nanoparticles. These magnetic and optical properties will be useful in various biomedical applications.</P>
Tegafaw, Tirusew,Xu, Wenlong,Lee, Sang Hyup,Chae, Kwon Seok,Chang, Yongmin,Lee, Gang Ho World Scientific Publishing Company 2017 International Journal of Modern Physics B Vol.31 No.4
<P>Iron (Fe)-based nanoparticles are extremely valuable in biomedical applications owing to their low toxicity and high magnetization values at room temperature. In this study, we synthesized nearly monodisperse iron oxide (Fe<SUB>3</SUB>O<SUB>4</SUB>) and Fe@Fe<SUB>3</SUB>O<SUB>4</SUB> (core: Fe, shell: Fe<SUB>3</SUB>O<TEX>$ _{4})$</TEX> nanoparticles in aqueous medium under argon flow and then, coated them with various biocompatible ligands and silica. In this study, eight types of surface-modified nanoparticles were investigated, namely, Fe<SUB>3</SUB>O<SUB>4</SUB>@PAA (PAA = polyacrylic acid; <TEX>$ M_{w}$</TEX> of PAA = 5100 amu and 15,000 amu), Fe<SUB>3</SUB>O<SUB>4</SUB>@PAA-FA (FA = folic acid; <TEX>$ M_{w}$</TEX> of PAA = 5100 amu and 15,000 amu), Fe<SUB>3</SUB>O<SUB>4</SUB>@PEI-fluorescein (PEI = polyethylenimine; <TEX>$ M_{w}$</TEX> of PEI = 1300 amu), Fe@Fe<SUB>3</SUB>O<SUB>4</SUB>@PEI (<TEX>$ M_{w}$</TEX> of PEI = 10,000 amu), Fe<SUB>3</SUB>O<SUB>4</SUB>@SiO<SUB>2</SUB> and Fe@Fe<SUB>3</SUB>O<SUB>4</SUB>@SiO<SUB>2</SUB> nanoparticles. We characterized the prepared surface-modified nanoparticles using high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) absorption spectroscopy, a superconducting quantum interference device (SQUID), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy and confocal microscopy. Finally, we measured the cytotoxicity of the samples. The results indicate that the surface-modified nanoparticles are biocompatible and are potential candidates for various biomedical applications.</P>
Adibehalsadat Ghazanfari,Shanti Marasini,Tirusew Tegafaw,Son Long Ho,Xu Miao,Mohammad Yaseen Ahmad,Huan Yue,이강호,박지애,정기혜,장용민,오인택,채권석 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.74 No.3
Ultrasmall heavy metal-oxide nanoparticles can be utilized for highly enhancing contrasts in com- puted tomography (CT). In this study, ultrasmall Yb2O3 nanoparticles coated with biocompatible and hydrophilic D-glucuronic acid were for the rst time prepared through a simple one-step polyol process, and their X-ray attenuation properties were investigated by measuring phantom images and X-ray attenuation powers. The average particle diameter of the nanoparticles was estimated to be 2:1 0:1 nm by using transmission electron microscopy. The observed X-ray attenuation power was stronger than that of a commercial iodine CT contrast agent (i.e., Ultravistr) at the same atomic concentration and much stronger at the same number density, proving the potential of ultrasmall Yb2O3 nanoparticles for use as a powerful CT contrast agent.
Mohammad Yaseen Ahmad,차현실,오인택,Tirusew Tegafaw,XUMIAO,Son Long Ho,Shanti Marasini,Adibehalsadat Ghazanfari,Huan Yue,채권석,장용민,이강호 대한화학회 2018 Bulletin of the Korean Chemical Society Vol.39 No.4
We prepared gadolinium oxide (Gd2O3) nanoparticles (GNPs) coated with a trans‐activator of transcription (TAT) peptide with cell‐penetrating ability (i.e., TAT‐GNPs) through one‐pot process. We characterized the particle diameter, surface‐coating structure, water proton relaxivities, and in vitro cellular toxicities of the TAT‐GNPs. We measured in vivo T1 magnetic resonance images (MRI) in a model nude mouse with liver cancer prior and posterior to intravenous administration. The average particle diameter of the GNPs was 1.5 nm. The sample solution exhibited a longitudinal water proton relaxivity (r1) of 18.2/s/mM (r2/r1 = 1.6, r2 = transverse water proton relaxivity), which is four to five times higher than those of commercial Gd‐chelates. The in vivo T1 MRI exhibited positively (or T1) enhanced contrasts in the mouse liver cancer after intravenous administration, demonstrating that the TAT‐GNPs acted as an enhanced cancer‐imaging agent similar to the cancer‐targeting agent in T1 MRI.
Miao, Xu,Xu, Wenlong,Cha, Hyunsil,Chang, Yongmin,Oh, In Taek,Chae, Kwon Seok,Tegafaw, Tirusew,Ho, Son Long,Kim, Sung June,Lee, Gang Ho Elsevier 2019 APPLIED SURFACE SCIENCE - Vol.477 No.-
<P><B>Abstract</B></P> <P>Ultrasmall Gd<SUB>2</SUB>O<SUB>3</SUB> nanoparticles can potentially be used as a positive magnetic resonance imaging (MRI) contrast agent owing to their high content of Gd(III), which exhibits the highest spin magnetic moment of all elements due to its seven unpaired 4<I>f</I> electrons. Herein, the above nanoparticles (average diameter = 2.0 nm) were coated with hydrophilic biocompatible polyacrylic acids (PAAs) of different molecular weights (<I>M</I> <SUB>w</SUB> = 1200, 5100, 15000 Da), and the PAA-size-dependent relaxometric properties of the thus obtained composites were investigated. In addition, the biocompatibility of these composites was assessed by <I>in-vitro</I> cell viability measurements. Finally, dose-dependent <I>R</I> <SUB>1</SUB> map images were acquired, proving that PAA-coated nanoparticles can be used as a <I>T</I> <SUB>1</SUB> MRI contrast agent.</P> <P><B>Highlights</B></P> <P> <UL> <LI> PAA-coated ultrasmall Gd<SUB>2</SUB>O<SUB>3</SUB> nanoparticles showed PAA-size dependent relaxometric properties. </LI> <LI> Both <I>r</I> <SUB>1</SUB> and <I>r</I> <SUB>2</SUB> values decreased with increasing PAA size (<I>M</I> <SUB>w</SUB> = 1200, 5100, 15000 Da). </LI> <LI> All samples showed good biocompatibility. </LI> <LI> All samples can be potential <I>T</I> <SUB>1</SUB> MRI contrast agents. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Kattel, Krishna,Park, Ja Young,Xu, Wenlong,Bony, Badrul Alam,Heo, Woo Cheol,Tegafaw, Tirusew,Kim, Cho Rong,Ahmad, M Wasi,Jin, Seonguk,Baeck, Jong Su,Chang, Yongmin,Kim, Tae Jeong,Bae, Ji Eun,Chae, Kwo American Scientific Publishers 2013 Journal of Nanoscience and Nanotechnology Vol.13 No.11
<P>The water-soluble and biocompatible D-glucuronic acid coated Eu(OH)3 nanorods (average thickness x average length = 9.0 x 118.3 nm) have been prepared in one-pot synthesis. The D-glucuronic acid coated Eu(OH)3 nanorods showed a strong fluorescence at approximately 600 nm with a narrow emission band width. A cytotoxicity test by using DU145 cells showed that D-glucuronic acid coated Eu(OH)3 nanorods are not toxic up to 100 microM, making them a promising candidate for biomedical applications such as fluorescent imaging. The minimum Eu concentration needed for a conventional confocal imaging was estimated to be approximately 0.1 mM. Therefore, D-glucuronic acid coated Eu(OH)3 nanorods can be applied to fluorescent imaging. However, a very tiny magnetization of approximately 1.2 emu/g at room temperature and at an applied field of 5 tesla was observed. As a result, very small r1 and r2 water proton relaxivities were estimated, implying that surface coated Eu(OH)3 nanorods are not sufficient for MRI contrast agents.</P>