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Chitosan-coated Ferrite (Fe3O4) Nanoparticles as a T2 Contrast Agent for Magnetic Resonance Imaging
이일수,Sungwook Hong,장용민 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.56 No.3
Iron oxide (Fe3O4) nanoparticles coated with biocompatible chitosan were synthesized for use as an MRI (magnetic resonance imaging) contrast agent. The coating was performed simultaneously with the synthesis of the ferrite nanoparticles. A dynamic light-scattering spectrometer (DLS)and a transmission electron microscope (TEM) were used to measure the average diameter of the coated nanoparticles, which was 67.0 nm. Fourier transform infrared (FT-IR) measurements showed strong bonding of the chitosan molecules to the surfaces of the ferrite nanoparticles. The spin-lattice (T1) and the spin-spin (T2) relaxation times of the nuclear spins (hydrogen protons) in aqueous solutions of various concentrations of coated ferrite nanoparticles were determined using a nuclear magnetic resonance (NMR) spectrometer. Using these data, we found that the T1 and the T2 relaxivities of the nuclear spins in aqueous solutions of ferrite nanoparticles were 0.00291 and 0.0691 ppm−1sec−1, respectively. In particular, the value of the T2 relaxivity was much larger than that of the commercial contrast agent GD-DTPA (gadolinium diethylenetriamine penta-acetic acid). A 31.7% intensity loss in the T2 image of a rabbit liver was observed after injecting the aqueous solution of coated nanoparticles into the rabbit, which shows that our coated ferrite nanoparticles can be used as a T2 MRI contrast agent.
Relaxivities of Hydrogen Protons in Aqueous Solutions of Gold-coated Manganese Ferrite Nanoparticles
Tanveer Ahmad,Yousaf Iqbal,배홍섭,이일수,홍성욱,장용민,이재준 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.11
Manganese ferrite nanoparticles were synthesized using the reverse micelle method and were coated with gold. TEM (transmission electron microscope) pictures showed that the shapes of the synthesized nanoparticles were almost spherical with an average diameter of 12 nm and a standard error of 4 nm. The bonding status of gold on the nanoparticle surfaces was checked using a Fourier transform infrared spectrometer (FTIR). The T1 and the T2 relaxation times of the hydrogen protons in aqueous solutions of the coated manganese-ferrite nanoparticles were determined using magnetic resonance imaging (MRI). The 1/T1 and the 1/T2 versus concentration curves for the nanoparticles showed a linear dependence. The T1 and the T2 relaxivities were found to be r1 =6.01 ± 0.12 and r2 = 83.3 ± 0.55 mM−1s−1. The ratio of r2/r1 was 13.9; this is larger than the ratios of r2/r1 for commercial T2 MRI contrast agents, indicating that the nanoparticles studied herein can serve as a T2 contrast agent with high efficacy.
A Systematic Study on MR Contrast Agents for Constructing Specific Relaxation Times
Cho, Jang-Geun,Cho, Jee-Hyun,Lee, Chul-Hyun,Ahn, Sang-Doo Korean Magnetic Resonance Society 2010 Journal of the Korean Magnetic Resonance Society Vol.14 No.1
The water proton relaxation rates increase linearly with concentrations of contrast agents, and could be expressed as a function of the concentrations. In this paper, we have investigated MR properties of two different contrast agents, $GdCl_3$ and $CoCl_2$. Relaxivity coefficients were calculated from individual contrast agent solutions, and used for predicting relaxation rates at mixtures of two contrast agents. From the experimental results, we have discussed the feasibility of constructing water solutions with the desired relaxation times using specific mixtures of contrast agents.
A Systematic Study on MR Contrast Agents for Constructing Specific Relaxation Times
안상두,조재현,이철현,조장근 한국자기공명학회 2010 Journal of the Korean Magnetic Resonance Society Vol.14 No.1
The water proton relaxation rates increase linearly with concentrations of contrast agents, and could be expressed as a function of the concentrations. In this paper, we have investigated MR properties of two different contrast agents, GdCl3 and CoCl2. Relaxivity coefficients were calculated from individual contrast agent solutions, and used for predicting relaxation rates at mixtures of two contrast agents. From the experimental results, we have discussed the feasibility of constructing water solutions with the desired relaxation times using specific mixtures of contrast agents.
백아름,Hee-Kyung Kim,Ji-ung Yang,Garam Choi,김민섭,Art E. Cho,김연희,김소연,Bokyung Sung,Byeong Woo Yang,Heejin Seo,Gang-Ho Lee,Hun-Kyu Ryeom,정회수,이태관,Yongmin Chang 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.85 No.-
Ultra-high-field (UHF) magnetic resonance imaging (MRI) can open up new avenues in clinical diagnosticimaging. Its sensitivity can be further improved using contrast agents (CAs). Therefore, developing low-molecular-weight MR CAs that are efficient under UHF is crucial to ensure taking full advantage of MRimaging at UHF. Moreover, designing highly stable UHF liver-specific CA has been challenging. Here, usingdysprosium (Dy3+), which relaxes water protons via a Curie relaxation that increases T2 relaxationsubstantially with the magneticfield strength, we report a new macrocyclic liver specific Dy3+ complex(Dy[DO3A-EOB]). We observed a 7.06 times higher r2/r1 ratio of Dy[DO3A-EOB] at 9.4 T than that of 1.5 T,which suggests a superior negative-enhancing MR CA at UHF. In vivo MR imaging results furtherdemonstrated that Dy[DO3A-EOB] showed a much strong negative enhancement at UHF (9.4 T) thanunder a lowfield (1.5 T). It was also found that, in addition to the ligand structure, the metal itself plays animportant role in determining the liver uptake pattern of the CA. Therefore, we successfullydemonstrated thefirst example of a small-molecular-weight liver-specific Dy3+ complex acting as aT2 CA with high sensitivity at UHF for diagnosis of liver diseases.
Ultrasmall iron oxide nanoparticles: Synthesis, physicochemical, and magnetic properties
Bae, S.J.,Park, J.A.,Lee, J.J.,Lee, G.H.,Kim, T.J.,Yoo, D.S.,Chang, Y. Elsevier 2009 CURRENT APPLIED PHYSICS Vol.9 No.1
A new synthetic method leading to the formation of polycaprolactone (PCL)/iron oxide nanoparticles using polyvinylpyrrolidone (PVP) is described. The unique feature of this method is that the conventional polymerization step can be avoided. A stable colloidal dispersion of the PCL-coated iron oxide nanoparticles (PCLNP) is thus formed in the presence of PVP as a stabilizer. The PCLNP has a mean diameter of 20-50nm as measured by TEM. Magnetic measurement by SQUID shows that the PCLNP has a strong superparamagnetism to be used as a liver MR T2 agent.
Ultrasmall iron oxide nanoparticles: Synthesis, physicochemical, and magnetic properties
Sung-Jin Bae,박지애,Jae-Jun Lee,Gang-Ho Lee,Tae-Jeong Kim,Done-Sik Yoo,장용민 한국물리학회 2009 Current Applied Physics Vol.9 No.11
A new synthetic method leading to the formation of polycaprolactone (PCL)/iron oxide nanoparticles using polyvinylpyrrolidone (PVP) is described. The unique feature of this method is that the conventional polymerization step can be avoided. A stable colloidal dispersion of the PCL-coated iron oxide nanoparticles (PCLNP) is thus formed in the presence of PVP as a stabilizer. The PCLNP has a mean diameter of 20–50 nm as measured by TEM. Magnetic measurement by SQUID shows that the PCLNP has a strong superparamagnetism to be used as a liver MR T2 agent.