Korea University · Medicine
Professor Hyuk Choi's research lab specializes in the investigation of magnetic and interfacial phenomena at the nanoscale, with a focus on spintronics, magnetic thin films, and their applications in biomedical and energy-related technologies. The lab explores how atomic-scale surface structures—such as steps and strain—control magnetic anisotropy, Curie temperature, and spin reorientation in transition metal films. It also extends into biointerfaces and low-level light therapy, examining how optical and mechanical stimuli modulate inflammatory responses in tissues. Additionally, the lab develops microfluidic platforms for high-throughput isolation of rare cells, such as circulating tumor cells, using viscoelastic flows.
Figures are computed from collected data and may differ slightly.
Two [2n]trannulene rings coupled through n C-C bonds dictate the properties and aromaticity of [n]cyclacenes (one possible valence isomer is shown schematically). Theoretical calculations indicate that [n]cyclacenes with even values of n constitute a novel class of organic semiconductors and magnetic materials.
Cation-pi interactions are important forces in molecular recognition by biological receptors, enzyme catalysis, and crystal engineering. We have harnessed these interactions in designing molecular systems with circular arrangement of benzene units that are capable of acting as ionophores and models for biological receptors. [n]Collarenes are promising candidates with high selectivity for a specific cation, depending on n, because of their structural rigidity and well-defined cavity size. The int
Fe films grown in ultrahigh vacuum onto a curved Pd(001) substrate with a continuous gradient in atomic step density were studied in situ via the surface magneto-optic Kerr effect (SMOKE). The steps induce an in-plane, uniaxial magnetic anisotropy with the easy axis perpendicular to the step edges, and whose strength scales linearly with step density. The Curie temperature of 1--2 monolayers of Fe is enhanced by the steps relative to that on a flat substrate. The enhancement is attributed to a s
Intervertebral disc degeneration (IVD) is one of the important causes of low back pain and is associated with inflammation induced by interaction between macrophages and the human annulus fibrosus (AF) cells. Low-level light therapy (LLLT) has been widely known to regulate inflammatory reaction. However, the effect of LLLT on macrophage-mediated inflammation in the AF cells has not been studied till date. The aim of this study is to mimic the inflammatory microenvironment and to investigate the
Ultrathin Fe films were grown epitaxially onto a stepped W(001) substrate, polished with a curvature to provide a continuously variable step density, with the steps parallel to the [100] crystalline axis. The steps induce an in-plane uniaxial magnetic anisotropy with easy axis perpendicular to the step edges. We found that this step-induced magnetic anisotropy does not enhance the Curie temperature of the Fe film. The strength of the anisotropy varies quadratically with step density, but does no
Combination of anionic [V10O28]6- and cationic [AlO4Al12(OH)24(H2O)12]7+ polyoxometalate clusters in an aqueous solution resulted in immediate hydrogel precipitation formation. This gel has the clusters in a 1:1 ratio arranged alternatively to form a short-range ordering. The precipitate, upon drying at room temperature, converts into a monolithic gel probably through the condensation of the [AlO4Al12(OH)24(H2O)12]7+ clusters as evidenced by the change of 27Al solid-state MAS NMR data.
Circulating tumor cells (CTCs) have attracted increasing attention as important biomarkers for clinical and biological applications. Several microfluidic approaches have been demonstrated to separate CTCs using immunoaffinity or size difference from other blood cells. This study demonstrates a sheathless, high-throughput separation of CTCs from white blood cells (WBCs) using a viscoelastic fluid. To determine the fluid viscoelasticity and the flow rate for CTC separation, and to validate the dev
Zwei [2n]Trannulen-Ringe, die über n C-C-Bindungen gekoppelt sind, bestimmen die Eigenschaften und die Aromatizität von [n]Cyclacenen (abgebildet ist ein Ausschnitt aus einem möglichen Valenzisomer). Theoretischen Rechnungen zufolge bilden [n]Cyclacene mit geradzahligen Werten von n eine neue Klasse organischer Halbleiter und magnetischer Materialien.
The possible utilization of [n]beltenes as a new family of ionophores, which exhibit a cation-olefinic pi type of interaction in contrast to the cation-aromatic pi type of interaction exhibited by [n]collarenes, has been investigated using both ab initio calculations and molecular dynamic simulations. Like [n]collarenes, n ethene groups are linked by -CH(2)- linkages in the [n]beltenes. Our calculations indicate that these [n]beltenes exhibit strong binding affinities and high selectivity for al
Although allergic rhinitis is not life threatening, it significantly influences the quality of a patient's life. This study is intended to evaluate the safety and efficacy of phototherapy with low-level energy of a 650 nm laser irradiation system in perennial allergic rhinitis patients. This clinical trial was an open-label, single-center study with 42 perennial allergic rhinitis subjects. Following laser irradiation in the nasal cavity with a laser irradiation system, the efficacy at weeks 1 th
Molecular level studies of intermolecular interaction forces and microscopic structures are essential to understand molecular aggregates and self-assembly phenomena. Recently, fibrous helicenebisquinone (HBQ) aggregates have been of great interest because of their strongly enhanced nonlinear optical (NLO) properties. The intermolecular interaction force and microscopic structure of HBQ aggregates were proposed to be donor−acceptor interaction and a columnar stack, respectively. However, our pres
Decavanadate (V10O286-) polyoxometalate (POM) ions in water decompose into smaller POM ions or monomeric H2VO4- when the pH is raised to higher than 6. In this report, however, we have found that silicate ions can kinetically stabilize decavanadate ions for up to 8 h at pH 12 conditions. Gelation of these solutions by lowering the pH to 4−5 followed by aging produced monolithic vanadia−silica composite gels with a wide range of vanadium contents (V/(V + Si) up to 48%). Solid state 51V NMR and in
Spin reorientation transition (SRT) of Fe film in the magnetically coupled Fe/Cu/Ni/Cu(001) system was investigated by surface magneto-optic Kerr effect and photoemission electron microscopy. We found that the Fe in-plane magnetic remanence within the SRT region oscillates with the Cu layer thickness with a periodicity exactly half of that of the magnetic interlayer coupling. Element specific domain imaging shows that the Fe stripe domains within the SRT region are washed away by the magnetic in
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