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Synthesis of Silicon Nanoparticles for Hyperpolarized <sup>29</sup>Si Magnetic Resonance Imaging
최익장,서형림,고혜지,공경현,정기진,박희정,이영복 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1
Silicon-based nanoparticles have been attracting lots of interest in the field of biomedical applications due to their biocompatibility. Here, we demonstrate two different synthetic approaches in order to yield various nano-sized silicon nanoparticles ranging from 5 nm to 500 nm as hyperpolarized MR contrast agents. i) The particles were synthesized by means of a chemical reduction of micelles. ii) Silica nanoparticles prepared by Stober method was treated with magnesium at a high temperature so as to produce crystalline Si NPs. The Si NPs show extremely long depolarization times, resulting in high MR image contrast with minimum background signals. In addition, paramagnetic centers on the surface defect sites play a pivotal role in generating MR signal enhancement induced by DNP mechanism, thereby not necessary to add external radical sources. In conclusion, these benefits suggest that the Si NPs can be used as biocompatible and targetable contrast agents.
Reliable multivariate calibration methods for near-infraredspectroscopic analysis
최익장,정기진,고혜지,공경현,이영복 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0
Near-infrared (NIR) spectroscopy has been extensively utilized in the field of petrochemical and semiconductor industries over the past twenty years. The major advantages of using NIR spectroscopy in these fields are based on its ability for fast and simultaneous multi-compositional detection (calibration model) of gasoline, naphtha, and etching solutions in an on-line system. However, special cares during the modeling process are strongly required to build up selective and accurate on-line calibration models because of compositional complexity of the petroleum- drive products and semiconductor etching solutions, as well as intrinsic broad spectral features of NIR spectrum. In order to establish the robust calibration process, here we presents two technical approaches, namely spectral range optimization (SRO) and pure component selectivity analysis (PCSA).
Study of micelle`s dynamics with nuclear magnetic resonance spectroscopy
공경현,이영복,고혜지,정기진,최익장 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0
Block copolymer micelles have been widely used in biomedical and cosmetic fields as delivery materials because of a specific targeting and delivering drugs / anti-aging components. In order to evaluate a performance of micelle, various Nuclear Magnetic Resonance (NMR) parameters such as chemical shifts, T1, T2 relaxation time and diffusion coefficient value which represent dynamic information of a micelle core part that is flexibility and mobility are studied. Herein, we researched micelles which are composed of diblock and triblock copolymer through a high resolution NMR that is powerful method in examining atomic level information. First of all, we investigated critical micelle concentrations(CMC) and thermo stability of core parts following a change of concentration and temperature respectively by using the NMR parameters. Then, stability differences of delivery fuctional part were confirmed in existence / nonexistence condition of lecithin which is an emulsifying agent. Additionally, with the preceding whole data,we evaluated a performance of micelles as delivery materals.
Hyperpolarization: Sensitivity Boost in Magnetic Resonance Spectroscopy and Imaging
고혜지,공경현,정기진,최익장,서형림,이영복 한국자기공명학회 2015 Journal of the Korean Magnetic Resonance Society Vol.19 No.3
Hyperpolarization methods are the most emerging techniques in the field of magnetic resonance (MR) researches since they make a contribution to overcoming sensitivity limitation of MR spectroscopy and imaging, leading to new fields of researches, real-time in vivo metabolic/molecular imaging and MR analysis of chemical/biological reactions in non-equilibrium conditions. Make use of enormous signal enrichments, it becomes feasible to investigate various chemical and biochemical systems with low γ nuclei in real-time. This review deals with the theoretical principals of common hyperpolarization methods and their experimental features. In addition, more detailed theories, mechanisms, and applications of dissolution dynamic nuclear polarization (D-DNP) are discussed.
정기진,이지욱,공경현,고혜지,최익장,서형림,이영복,Niki M. Zacharias Millward,Pratip K. Bhattacharya 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.36 No.-
We utilized dynamic nuclear polarization to hyperpolarize three metabolic imaging agents as singleagents and together (co-polarization with two different organic radicals; OX63 and BDPA). In addition,we describe our initial two slice selective spectroscopy in vivo experiments in mice. These techniquesalong with advances by other laboratories will allow for multiple metabolic pathways to be imaged inreal-time and in vivo.