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Ultrasensitive capsaicin sensor based on endogenous single-molecule fluorophore enhancement and quenching interface on gold nanoislands (GNIs) was developed by correlative fluorescence fluctuation optical spectroscopy. Endogenous fluorescence of capsaicinoids was enhanced by plasmon resonance energy transfer in the proximity of GNIs. The enhanced fluorescence signals exhibited large fluctuation from the average intensity reflecting the characteristic to-and-fro Brownian motion of fluorophores to the proximity of GNIs. The fluctuation of fluorophores showed enhancement, quenching, and equilibrium lifetimes depending on fluorophore-GNI distance. The correlation diffusion of fluorophore signal decreased with increasing concentration of capsaicinoids. In the cross-correlative quantification of capsaicinoids using the GNI array chip, the method showed excellent detection limits of 290 zM for capsaicin and 467 zM for dihydrocapsaicin. This method consisting of fluorophore fluctuation analysis and correlation diffusion-based quantification has potential application to the study of label-free single-molecule interactions.
Suresh Kumar Chakkarapani; Seungah Lee; Seong Ho Kang. Ultrasensitive Capsaicin Sensor Based on Endogenous Single‐Molecule Fluorophore Enhancement and Quenching Interface on Gold Nanoislands. Bulletin of the Korean Chemical Society 2021, 1 .
AMA StyleSuresh Kumar Chakkarapani, Seungah Lee, Seong Ho Kang. Ultrasensitive Capsaicin Sensor Based on Endogenous Single‐Molecule Fluorophore Enhancement and Quenching Interface on Gold Nanoislands. Bulletin of the Korean Chemical Society. 2021; ():1.
Chicago/Turabian StyleSuresh Kumar Chakkarapani; Seungah Lee; Seong Ho Kang. 2021. "Ultrasensitive Capsaicin Sensor Based on Endogenous Single‐Molecule Fluorophore Enhancement and Quenching Interface on Gold Nanoislands." Bulletin of the Korean Chemical Society , no. : 1.
Considering the importance of biogenic amines (BAs), such as histamine, tyramine, and putrescine, as biomarkers and the challenges in their simultaneous detection at low concentrations, a novel enhanced multiple nanoarray BA sensor was developed using a competitive reaction in an evanescent field (EF). BAs were bound to specific antibodies on different gold nanoarray islands on a multiple nanoarray sensor chip. The electromagnetic field in the EF produced fluorescence signals of BA-conjugated quantum dots with an excellent signal-to-noise ratio on the islands. Compared to conventional fluorescent dyes or plasmonic nanoparticles as detection probes, quantum dots showed improved detection sensitivity with excellent photostability. The competitive reaction in EF was simultaneously used to detect three BA molecules on the multiple nanoarray. The multiple BA sensor exhibited an excellent detection limit of 63 aM with a wide dynamic range of 100 aM–10 nM, which had a 1,000,000-fold higher sensitivity than that of previously reported methods. The proposed BA sensor was validated by high-performance liquid chromatography and enzyme-linked immunosorbent assay and was applied to identify BAs in wine samples. The results agreed with those of standard methods, showing 95 % confidence level. The combined competitive reaction and simultaneous detection of BA-conjugated quantum dots in EF on the multiple nanoarray sensor exhibited excellent enhancement of detection sensitivity. This high-throughput screening method shows highly specific labeling using promiscuous antibodies for detecting small molecules in complex matrices.
Huong Thi Thuy Nguyen; Seungah Lee; Junghwa Lee; Ji-Hyoung Ha; Seong Ho Kang. Ultrasensitive biogenic amine sensor using an enhanced multiple nanoarray chip based on competitive reactions in an evanescent field. Sensors and Actuators B: Chemical 2021, 345, 130354 .
AMA StyleHuong Thi Thuy Nguyen, Seungah Lee, Junghwa Lee, Ji-Hyoung Ha, Seong Ho Kang. Ultrasensitive biogenic amine sensor using an enhanced multiple nanoarray chip based on competitive reactions in an evanescent field. Sensors and Actuators B: Chemical. 2021; 345 ():130354.
Chicago/Turabian StyleHuong Thi Thuy Nguyen; Seungah Lee; Junghwa Lee; Ji-Hyoung Ha; Seong Ho Kang. 2021. "Ultrasensitive biogenic amine sensor using an enhanced multiple nanoarray chip based on competitive reactions in an evanescent field." Sensors and Actuators B: Chemical 345, no. : 130354.
The contact distance between mitochondria (Mito) and endoplasmic reticulum (ER) has received considerable attention owing to their crucial function in maintaining lipid and calcium homeostasis.
Yucheng Sun; Seungah Lee; Seong Ho Kang. Cubic spline-based depth-dependent localization of mitochondria-endoplasmic reticulum contacts by three-dimensional light-sheet super-resolution microscopy. The Analyst 2021, 146, 4781 -4788.
AMA StyleYucheng Sun, Seungah Lee, Seong Ho Kang. Cubic spline-based depth-dependent localization of mitochondria-endoplasmic reticulum contacts by three-dimensional light-sheet super-resolution microscopy. The Analyst. 2021; 146 (15):4781-4788.
Chicago/Turabian StyleYucheng Sun; Seungah Lee; Seong Ho Kang. 2021. "Cubic spline-based depth-dependent localization of mitochondria-endoplasmic reticulum contacts by three-dimensional light-sheet super-resolution microscopy." The Analyst 146, no. 15: 4781-4788.
The natural characteristics of deoxyribonucleic acid (DNA) enable its advanced applications in nanotechnology as a special tool that can be detected by high-resolution imaging with precise localization. Super-resolution (SR) microscopy enables the examination of nanoscale molecules beyond the diffraction limit. With the development of SR microscopy methods, DNA nanostructures can now be optically assessed. Using the specific binding of fluorophores with their target molecules, advanced single-molecule localization microscopy (SMLM) has been expanded into different fields, allowing wide-range detection at the single-molecule level. This review discusses the recent progress in the SR imaging of DNA nano-objects using SMLM techniques, such as direct stochastic optical reconstruction microscopy, binding-activated localization microscopy, and point accumulation for imaging nanoscale topography. Furthermore, we discuss their advantages and limitations, present applications, and future perspectives.
Seungah Lee; Indra Batjikh; Seong Ho Kang. Toward Sub-Diffraction Imaging of Single-DNA Molecule Sensors Based on Stochastic Switching Localization Microscopy. Sensors 2020, 20, 6667 .
AMA StyleSeungah Lee, Indra Batjikh, Seong Ho Kang. Toward Sub-Diffraction Imaging of Single-DNA Molecule Sensors Based on Stochastic Switching Localization Microscopy. Sensors. 2020; 20 (22):6667.
Chicago/Turabian StyleSeungah Lee; Indra Batjikh; Seong Ho Kang. 2020. "Toward Sub-Diffraction Imaging of Single-DNA Molecule Sensors Based on Stochastic Switching Localization Microscopy." Sensors 20, no. 22: 6667.
Exploiting the working principle of conventional differential interference contrast (DIC) microscopy, we experimentally investigate the non-paraxial Talbot effect of two-dimensional periodic arrays of gold nanodisks (AuNDs) with a periodicity ao comparable to the excitation wavelength λ.
Geun Wan Kim; Seong Ho Kang; Ji Won Ha. Characterizing the non-paraxial Talbot effect of two-dimensional periodic arrays of plasmonic gold nanodisks by differential interference contrast microscopy. The Analyst 2020, 145, 7541 -7545.
AMA StyleGeun Wan Kim, Seong Ho Kang, Ji Won Ha. Characterizing the non-paraxial Talbot effect of two-dimensional periodic arrays of plasmonic gold nanodisks by differential interference contrast microscopy. The Analyst. 2020; 145 (23):7541-7545.
Chicago/Turabian StyleGeun Wan Kim; Seong Ho Kang; Ji Won Ha. 2020. "Characterizing the non-paraxial Talbot effect of two-dimensional periodic arrays of plasmonic gold nanodisks by differential interference contrast microscopy." The Analyst 145, no. 23: 7541-7545.
Voltage program (VP)-based micellar electrokinetic chromatography (MEKC) with a laser-induced fluorescence (LIF) detector was developed for fast, high-sensitivity detection of native capsaicin (CAP) and dihydrocapsaicin (DHC) in various foods. The combination of mixed nonionic (Tween 20) and anionic (SDS) surfactants in a sodium borate running buffer showed excellent separation efficiency, selectivity, and speed without loss of resolving power (Rs > 2). Compared to conventional UV absorption, LIF showed enhanced detection sensitivity with detection limits at the pM level. In addition, the developed VP-based MEKC-LIF method was successfully applied for quantification of capsaicin in chili pepper, baechu, and kimchi at a 98% confidence level. CAP and DHC were also analyzed within a short time in extracts from real samples of gochujang, snacks (Swingchip®), black pepper, and ginger but were not detected in garlic.
Yucheng Sun; Boyeon Park; Ji-Hyoung Ha; Seong Ho Kang. Voltage program-based MEKC with LIF detection for rapid quantification of native capsaicin and dihydrocapsaicin in foods. Food Chemistry 2020, 323, 126831 .
AMA StyleYucheng Sun, Boyeon Park, Ji-Hyoung Ha, Seong Ho Kang. Voltage program-based MEKC with LIF detection for rapid quantification of native capsaicin and dihydrocapsaicin in foods. Food Chemistry. 2020; 323 ():126831.
Chicago/Turabian StyleYucheng Sun; Boyeon Park; Ji-Hyoung Ha; Seong Ho Kang. 2020. "Voltage program-based MEKC with LIF detection for rapid quantification of native capsaicin and dihydrocapsaicin in foods." Food Chemistry 323, no. : 126831.
For stem cell-based therapies, the fate and distribution of stem cells should be traced using non-invasive or histological methods and a nanomaterial-based labelling agent. However, evaluation of the biophysical effects and related biological functions of nanomaterials in stem cells remains challenging. Here, we aimed to investigate the biophysical effects of nanomaterials on stem cells, including those on membrane fluidity, using total internal reflection fluorescence microscopy, and traction force, using micropillars of human bone marrow-derived mesenchymal stem cells (hBM-MSCs) labelled with silica-coated magnetic nanoparticles incorporating rhodamine B isothiocyanate ([email protected](RITC)). Furthermore, to evaluate the biological functions related to these biophysical changes, we assessed the cell viability, reactive oxygen species (ROS) generation, intracellular cytoskeleton, and the migratory activity of [email protected](RITC)-treated hBM-MSCs. Compared to that in the control, cell viability decreased by 10% and intracellular ROS increased by 2-fold due to the induction of 20% higher peroxidized lipid in hBM-MSCs treated with 1.0 µg/µL [email protected](RITC). Membrane fluidity was reduced by [email protected](RITC)-induced lipid oxidation in a concentration-dependent manner. In addition, cell shrinkage with abnormal formation of focal adhesions and ~30% decreased total traction force were observed in cells treated with 1.0 µg/µL [email protected](RITC) without specific interaction between [email protected](RITC) and cytoskeletal proteins. Furthermore, the migratory activity of hBM-MSCs, which was highly related to membrane fluidity and cytoskeletal abnormality, decreased significantly after [email protected](RITC) treatment. These observations indicated that the migratory activity of hBM-MSCs was impaired by [email protected](RITC) treatment due to changes in stem-cell biophysical properties and related biological functions, highlighting the important mechanisms via which nanoparticles impair migration of hBM-MSCs. Our findings indicate that nanoparticles used for stem cell trafficking or clinical applications should be labelled using optimal nanoparticle concentrations to preserve hBM-MSC migratory activity and ensure successful outcomes following stem cell localisation.
Tae Hwan Shin; Da Yeon Lee; Abdurazak Aman Ketebo; Seungah Lee; Balachandran Manavalan; Shaherin Basith; Chanyoung Ahn; Seong Ho Kang; Sungsu Park; Gwang Lee. Silica-Coated Magnetic Nanoparticles Decrease Human Bone Marrow-Derived Mesenchymal Stem Cell Migratory Activity by Reducing Membrane Fluidity and Impairing Focal Adhesion. Nanomaterials 2019, 9, 1475 .
AMA StyleTae Hwan Shin, Da Yeon Lee, Abdurazak Aman Ketebo, Seungah Lee, Balachandran Manavalan, Shaherin Basith, Chanyoung Ahn, Seong Ho Kang, Sungsu Park, Gwang Lee. Silica-Coated Magnetic Nanoparticles Decrease Human Bone Marrow-Derived Mesenchymal Stem Cell Migratory Activity by Reducing Membrane Fluidity and Impairing Focal Adhesion. Nanomaterials. 2019; 9 (10):1475.
Chicago/Turabian StyleTae Hwan Shin; Da Yeon Lee; Abdurazak Aman Ketebo; Seungah Lee; Balachandran Manavalan; Shaherin Basith; Chanyoung Ahn; Seong Ho Kang; Sungsu Park; Gwang Lee. 2019. "Silica-Coated Magnetic Nanoparticles Decrease Human Bone Marrow-Derived Mesenchymal Stem Cell Migratory Activity by Reducing Membrane Fluidity and Impairing Focal Adhesion." Nanomaterials 9, no. 10: 1475.
Norovirus (NoV) is a major foodborne pathogen, and even low levels of virus can cause infection and gastroenteritis. We developed a supersensitive NoV sensor that detects NoV group-I capsid protein (NoVP) via three-dimensional (3D) total internal reflection scattering defocus microscopy (TIRSDM) with wavelength-dependent transmission grating (TG). The combination of evanescent wave scattering and TG significantly enhanced the detection sensitivity and selectivity of NoVP in first-order spectral images (n = +1) by minimizing spectroscopic interference and background noise. In particular, wavelength-dependent 3D defocused TG imaging (3D TG-TIRSDM) separated silver nanotag and gold nanoplate signals on a NoVP immunoplasmon chip along the x, y, and z coordinates simultaneously. Additionally, the use of wavelength-dependent TG increased the spectral resolution by 5-fold along the xy-axis and 1.4-fold along the z-axis compared to conventional 3D TIRSDM at the subdiffraction limit. The NoVP sensor exhibited a lower limit of detection of 820 yM, which is 29 000 times better than the previous potentiometer method, and a wide dynamic detection range of 820 yM to 92.45 pM (R = 0.9801). This new method could be applied to detect various pathogenic viruses during the initial stage of infection.
Seungah Lee; Sujin Ahn; Suresh Kumar Chakkarapani; Seong Ho Kang. Supersensitive Detection of the Norovirus Immunoplasmon by 3D Total Internal Reflection Scattering Defocus Microscopy with Wavelength-Dependent Transmission Grating. ACS Sensors 2019, 4, 2515 -2523.
AMA StyleSeungah Lee, Sujin Ahn, Suresh Kumar Chakkarapani, Seong Ho Kang. Supersensitive Detection of the Norovirus Immunoplasmon by 3D Total Internal Reflection Scattering Defocus Microscopy with Wavelength-Dependent Transmission Grating. ACS Sensors. 2019; 4 (9):2515-2523.
Chicago/Turabian StyleSeungah Lee; Sujin Ahn; Suresh Kumar Chakkarapani; Seong Ho Kang. 2019. "Supersensitive Detection of the Norovirus Immunoplasmon by 3D Total Internal Reflection Scattering Defocus Microscopy with Wavelength-Dependent Transmission Grating." ACS Sensors 4, no. 9: 2515-2523.
Studies on the properties of plasmonic materials and new chemical biological sensors are very important to our understanding of biological systems in single cells. Since the advent of nanofabrication techniques, plasmonic nanostructures have been widely used in various research fields including material science, biology, and medicine. The optical, electronic and catalytic properties of plasmonic nanostructures can be tuned very broadly by controlling their size, shape, and composition. Traditional optical biosensors based on the plasmonic properties of nanostructures have led to the development of high sensitivity, temporal-spatially resolved, and high-throughput plasmonic optical imaging techniques through assembly optimization of light sources, detectors, and other optical components. These techniques have been applied to single-cell research. Here, we briefly provide various applications of plasmonic nanostructures used for single-cell analysis and summarize the advanced detection and imaging techniques at the single-cell level.
Seungah Lee; Yucheng Sun; Yingying Cao; Seong Ho Kang. Plasmonic nanostructure-based bioimaging and detection techniques at the single-cell level. TrAC Trends in Analytical Chemistry 2019, 117, 58 -68.
AMA StyleSeungah Lee, Yucheng Sun, Yingying Cao, Seong Ho Kang. Plasmonic nanostructure-based bioimaging and detection techniques at the single-cell level. TrAC Trends in Analytical Chemistry. 2019; 117 ():58-68.
Chicago/Turabian StyleSeungah Lee; Yucheng Sun; Yingying Cao; Seong Ho Kang. 2019. "Plasmonic nanostructure-based bioimaging and detection techniques at the single-cell level." TrAC Trends in Analytical Chemistry 117, no. : 58-68.
Endogenous fluorescence imaging techniques are key for modern single-molecule quantification without the use of additional labeling probes. However, the drawback of weak fluorescence signal is the primary challenge in meeting the ever-increasing demands of single-molecule detection. Here, we report a simple and reliable method that provides up to ∼100-fold uniform fluorescence enhancement of endogenous fluorescence of the capsaicinoid molecule. The method is based on a single nanoparticle plasmon-amplified endogenous fluorescence nanospectroscopic sensor (PAEFS). This work demonstrated the applicability of PAEFS in refining sensitivity at the single-molecule level by showing ultralow limits of detection (106 times lower than previous reports) of fluorescence-based capsaicinoids with a wide range of linear response (18 zM to 85 pM). Spectrally overlapped capsaicinoid analogues were quantified ratiometrically to detect the analogue percentages in real samples. The novel endogenous fluorescence enhancement approach presented here represents a universal sensor for enhanced detection of single molecules using existing techniques without altering the original molecular features or using add-on labeling probes.
Suresh Kumar Chakkarapani; Seungah Lee; Boyeon Park; Hye-Young Seo; Seong Ho Kang. Plasmon-Amplified Endogenous Fluorescence Nanospectroscopic Sensor Based on Inherent Elastic Scattering for Ultratrace Ratiometric Detection of Capsaicinoids. ACS Sensors 2019, 4, 953 -960.
AMA StyleSuresh Kumar Chakkarapani, Seungah Lee, Boyeon Park, Hye-Young Seo, Seong Ho Kang. Plasmon-Amplified Endogenous Fluorescence Nanospectroscopic Sensor Based on Inherent Elastic Scattering for Ultratrace Ratiometric Detection of Capsaicinoids. ACS Sensors. 2019; 4 (4):953-960.
Chicago/Turabian StyleSuresh Kumar Chakkarapani; Seungah Lee; Boyeon Park; Hye-Young Seo; Seong Ho Kang. 2019. "Plasmon-Amplified Endogenous Fluorescence Nanospectroscopic Sensor Based on Inherent Elastic Scattering for Ultratrace Ratiometric Detection of Capsaicinoids." ACS Sensors 4, no. 4: 953-960.
We report a non-covalent loading of ginsenoside compound K (CK) onto our previously reported gold nanoparticles (DCY51T-AuCKNps) through one-pot biosynthesis using a probiotic Lactobacillus kimchicus DCY51T isolated from Korean kimchi. The ginsenoside-loaded gold nanoparticles were characterized by various analytical and spectroscopic techniques such as field emission transmission electron microscopy (FE-TEM), energy-dispersive X-ray (EDX) spectroscopy, elemental mapping, X-ray powder diffraction (XRD), selected area electron diffraction (SAED), Fourier-transform infrared (FTIR) spectroscopy and dynamic light scattering (DLS). Furthermore, drug loading was also determined by liquid chromatography–mass spectrometry (LC–MS). In addition, DCY51T-AuNps and DCY51T-AuCKNps were resistant to aggregation caused by pH variation or a high ionic strength environment. Cell-based study confirmed that DCY51T-AuCKNps exhibited slightly higher cytotoxicity compared to ginsenoside CK treatment in A549 cells (human lung adenocarcinoma cell line) and HT29 (human colorectal adenocarcinoma cell line). Upon laser treatment, DCY51T-AuCKNps showed enhanced cell apoptosis in A549, HT29 and AGS cells (human stomach gastric adenocarcinoma cell line) compared with only DCY51T-AuCKNps treated cells. In conclusion, this preliminary study identified that DCY51T-AuCKNps act as a potent photothermal therapy agents with synergistic chemotherapeutic effects for the treatment of cancer.
Yeon-Ju Kim; Haribalan Perumalsamy; Josua Markus; Sri Renukadevi Balusamy; Chao Wang; Seong Ho Kang; Seungah Lee; Sang Yong Park; Sung Kim; Verónica Castro-Aceituno; Seung Hyun Kim; Deok Chun Yang. Development of Lactobacillus kimchicus DCY51T-mediated gold nanoparticles for delivery of ginsenoside compound K: in vitro photothermal effects and apoptosis detection in cancer cells. Artificial Cells, Nanomedicine, and Biotechnology 2019, 47, 30 -44.
AMA StyleYeon-Ju Kim, Haribalan Perumalsamy, Josua Markus, Sri Renukadevi Balusamy, Chao Wang, Seong Ho Kang, Seungah Lee, Sang Yong Park, Sung Kim, Verónica Castro-Aceituno, Seung Hyun Kim, Deok Chun Yang. Development of Lactobacillus kimchicus DCY51T-mediated gold nanoparticles for delivery of ginsenoside compound K: in vitro photothermal effects and apoptosis detection in cancer cells. Artificial Cells, Nanomedicine, and Biotechnology. 2019; 47 (1):30-44.
Chicago/Turabian StyleYeon-Ju Kim; Haribalan Perumalsamy; Josua Markus; Sri Renukadevi Balusamy; Chao Wang; Seong Ho Kang; Seungah Lee; Sang Yong Park; Sung Kim; Verónica Castro-Aceituno; Seung Hyun Kim; Deok Chun Yang. 2019. "Development of Lactobacillus kimchicus DCY51T-mediated gold nanoparticles for delivery of ginsenoside compound K: in vitro photothermal effects and apoptosis detection in cancer cells." Artificial Cells, Nanomedicine, and Biotechnology 47, no. 1: 30-44.
A fluorescence-free ultrasensitive norovirus nanoimmunosensor was investigated based on gradient-fitting super-localization by three-dimensional (3D) dual-view light sheet microscopy (DV-LSM). A highly contagious norovirus was detected by immunoreaction with 100-nm gold nanospots (AuNSs) and 40-nm silver nanoparticles (AgNPs) as imaging probes. Dual-view setup was added to the optical path to simultaneously image AgNP-labelled norovirus and AuNSs in real time. A cylindrical lens and dual-view identified axial distance differences between AuNS and AgNP images as a function of an elliptically distorted point spread function (PSF). Differences between PSFs in each plane at 10 nm slicing intervals were distinguished by gradient-fitting algorithm-based super-localization. This approach showed highly enhanced detection sensitivity and super-localization in the axial direction for norovirus. The axial distance between AuNS and AgNP in norovirus immnosensor was 23 ± 3 nm for 7.8 zM, and the distance increased with increased concentration. The method had an excellent limit of detection (LOD) of 7.8 zM with a wide linear dynamic range of 7.8 zM–240 aM. The LOD was 106 to 2,300,000 times lower than previous methods. Norovirus was detected in lettuce leaf extraction at 14.3 zM with 99.87% recovery. The 3D DV-LSM method with gradient-fitting super-localization was an effective method for ultra-trace norovirus detection at the single-molecule level with highly precise axial resolution.
Suresh Kumar Chakkarapani; Yucheng Sun; Seong Ho Kang. Ultrasensitive norovirus nanoimmunosensor based on concurrent axial super-localization of ellipsoidal point spread function by 3D light sheet microscopy. Sensors and Actuators B: Chemical 2018, 284, 81 -90.
AMA StyleSuresh Kumar Chakkarapani, Yucheng Sun, Seong Ho Kang. Ultrasensitive norovirus nanoimmunosensor based on concurrent axial super-localization of ellipsoidal point spread function by 3D light sheet microscopy. Sensors and Actuators B: Chemical. 2018; 284 ():81-90.
Chicago/Turabian StyleSuresh Kumar Chakkarapani; Yucheng Sun; Seong Ho Kang. 2018. "Ultrasensitive norovirus nanoimmunosensor based on concurrent axial super-localization of ellipsoidal point spread function by 3D light sheet microscopy." Sensors and Actuators B: Chemical 284, no. : 81-90.
The catalytic properties of supported catalysts are greatly influenced by the nature of the support. Here, by monitoring the nanocatalysis of gold (Au) nanoparticles deposited on the outer surface (Au/CNTs‐out) and inner surface (Au/CNTs‐in) of CNTs at the single‐molecule level, the support effect of CNTs was observed in both product formation process and product dissociation process. The results indicated that Au/CNTs‐out possessed higher intrinsic catalytic activity than Au/CNTs‐in in reductive N‐deoxygenation reaction of resazurin to resorufin. For the product dissociation process, the product molecules on both Au/CNTs‐out and Au/CNTs‐in preferred the reactant‐assisted dissociation pathway. Furthermore, product molecules dissociated faster on Au/CNTs‐out than Au/CNTs‐in. These differences were attributed to the support effect of CNTs. This study shows a better understanding of support effect for supported catalyst and gives deeper insight into heterogeneous catalytic process.
Yingying Cao; Seong Ho Kang. Single-Molecule Nanocatalysis Via the Support Effect of Gold Nanoparticles on Carbon Nanotubes. Bulletin of the Korean Chemical Society 2018, 40, 14 -19.
AMA StyleYingying Cao, Seong Ho Kang. Single-Molecule Nanocatalysis Via the Support Effect of Gold Nanoparticles on Carbon Nanotubes. Bulletin of the Korean Chemical Society. 2018; 40 (1):14-19.
Chicago/Turabian StyleYingying Cao; Seong Ho Kang. 2018. "Single-Molecule Nanocatalysis Via the Support Effect of Gold Nanoparticles on Carbon Nanotubes." Bulletin of the Korean Chemical Society 40, no. 1: 14-19.
Glutathione S-transferase (GST) polymorphism (M1 = 215 bp and T1 = 480 bp) can cause liver damage and increase the risk of cancer. In this study, voltage programming (VP)-based microchip electrophoresis (ME) with a laser-induced fluorescence (LIF) detector was developed to detect specific sizes of DNA fragments. The optimum conditions for a single-channel microchip were as follows: 4 kV for 0–9.5 s, 1.5 kV for 9.5–15.5 s, and 4 kV for 15.5–30 s. Next, these conditions were applied to another microchip that was constructed with many channels making possible simultaneous parallel detection. Finally, GST genes extracted from human blood were amplified by polymerase chain reaction (PCR) and were introduced into the multi-channel microchip. Target DNA molecules amplified by only 10 PCR cycles could be detected by the VP-based multi-channel ME method, but not by slab gel electrophoresis (SGE). In addition, the migration time for ME was <15 s, which was 700 times faster than conventional SGE. The developed VP-based multi-channel ME method with LIF detection was demonstrated to be an effective, rapid analysis technique for highly sensitive and high-throughput screening of GST genes.
Yucheng Sun; Su-Kang Kim; Seong Ho Kang. Fast high-throughput screening of glutathione S-transferase polymorphism by voltage programming-based multi-channel microchip electrophoresis. Journal of Chromatography B 2018, 1097-1098, 10 -17.
AMA StyleYucheng Sun, Su-Kang Kim, Seong Ho Kang. Fast high-throughput screening of glutathione S-transferase polymorphism by voltage programming-based multi-channel microchip electrophoresis. Journal of Chromatography B. 2018; 1097-1098 ():10-17.
Chicago/Turabian StyleYucheng Sun; Su-Kang Kim; Seong Ho Kang. 2018. "Fast high-throughput screening of glutathione S-transferase polymorphism by voltage programming-based multi-channel microchip electrophoresis." Journal of Chromatography B 1097-1098, no. : 10-17.
The migration behavior of organic fluorescent dyes (i.e., crystal violet, methyl violet base, methyl violet B base, rhodamine 6G, and rhodamine B base) in non-aqueous capillary electrophoresis (NACE) was investigated by focusing on the physicochemical properties of various organic solvents [ethanol, methanol, 2-propanol, dimethylformamide (DMF), and dimethyl sulfoxide (DMSO)] in background electrolyte (BGE). Laser-induced fluorescence (LIF) and UV/Vis detectors were employed to observe both the migration time of organic dyes and the electroosmotic flow (EOF) in NACE, respectively. As seen in conventional aqueous BGE, the mobility of EOF in organic solvents tended to rise when the ratio between the dielectric constant and the solvent’s viscosity (ε/η) increased in accordance with Smoluchowski’s equation. However, unlike the ε/η of pure organic solvents, the migration order of dyes changed as follows: methanol (60.0) > DMF (45.8) > ethanol (22.8) > DMSO (23.4) > 2-propanol (9.8). Since the amount of acetic acid added to balance the pH depends on the pKa of each solvent, EOF changed when the difference in the ε/η value was small. This resulted from the inhibition of mobility, and its difference was dependent on the ε/η of BGEs with high ionic strength. In particular, the actual mobility of dyes in DMF showed excellent compliance with the Debye–Hückel–Onsager (DHO) theory extended by Falkenhagen and Pitts, which enabled us to analyze all dyes within 15 min with excellent resolution (Rs > 2.5) under optimum NACE conditions (10 mM sodium borate and 4661 mM acetic acid in 100% DMF, pH 4.5). In addition, the NACE method was successfully applied for analyzing commercially available ballpoint ink pens. Thus, these results could be used to anticipate the migration order of organic dyes in a 100% NACE separation system.
Minjeong Gu; Keunchang Cho; Seong Ho Kang. Migration behavior of organic dyes based on physicochemical properties of solvents as background electrolytes in non-aqueous capillary electrophoresis. Journal of Chromatography A 2018, 1560, 82 -90.
AMA StyleMinjeong Gu, Keunchang Cho, Seong Ho Kang. Migration behavior of organic dyes based on physicochemical properties of solvents as background electrolytes in non-aqueous capillary electrophoresis. Journal of Chromatography A. 2018; 1560 ():82-90.
Chicago/Turabian StyleMinjeong Gu; Keunchang Cho; Seong Ho Kang. 2018. "Migration behavior of organic dyes based on physicochemical properties of solvents as background electrolytes in non-aqueous capillary electrophoresis." Journal of Chromatography A 1560, no. : 82-90.
Three-dimensional (3D) orientations of individual anisotropic plasmonic nanoparticles in aggregates were observed in real time by integrated light sheet super-resolution microscopy (iLSRM). Asymmetric light scattering of a gold nanorod (AuNR) was used to trigger signals based on the polarizer angle. Controlled photo-switching was achieved by turning the polarizer and obtaining a series of images at different polarization directions. 3D sub-diffraction limited super-resolution images were obtained by super-localization of scattering signals as a function of the anisotropic optical properties of AuNRs. Varying the polarizer angle allowed resolution of the orientation of individual AuNRs. 3D images of individual nanoparticles were resolved in aggregated regions, resulting in as low as 64 nm axial resolution and 28 nm spatial resolution. The proposed imaging setup and localization approach demonstrates a convenient method for imaging under a noisy environment where the majority of scattering noise comes from cellular components. This integrated 3D iLSRM and localization technique was shown to be reliable and useful in the field of 3D non-fluorescence super-resolution imaging.
Suresh Kumar Chakkarapani; Yucheng Sun; Seungah Lee; Ning Fang; Seong Ho Kang. Three-Dimensional Orientation of Anisotropic Plasmonic Aggregates at Intracellular Nuclear Indentation Sites by Integrated Light Sheet Super-Resolution Microscopy. ACS Nano 2018, 12, 4156 -4163.
AMA StyleSuresh Kumar Chakkarapani, Yucheng Sun, Seungah Lee, Ning Fang, Seong Ho Kang. Three-Dimensional Orientation of Anisotropic Plasmonic Aggregates at Intracellular Nuclear Indentation Sites by Integrated Light Sheet Super-Resolution Microscopy. ACS Nano. 2018; 12 (5):4156-4163.
Chicago/Turabian StyleSuresh Kumar Chakkarapani; Yucheng Sun; Seungah Lee; Ning Fang; Seong Ho Kang. 2018. "Three-Dimensional Orientation of Anisotropic Plasmonic Aggregates at Intracellular Nuclear Indentation Sites by Integrated Light Sheet Super-Resolution Microscopy." ACS Nano 12, no. 5: 4156-4163.
Tumor necrosis factor-α (TNF-α) is a significant mediator of autoimmune diseases and an inflammatory protein biomarker. A novel method for the immunotargeting of TNF-α has been developed using three-dimensional (3D) enhanced dark-field super-resolution microscopy (3D EDF-SRM) based on ultra-sensitive dual-code plasmonic nanosensing. Dual-code EDF-based 3D SRM improved the localization precision and sensitivity with a least-cubic algorithm, which provides accurate position information for the immunotargeted site. A dual-view device and digital single lens reflex (DSLR) camera were used for simultaneous dual confirmable quantitative and qualitative immunoscreening based on enhanced dark-field scattering images. Two different sizes of silver nanoparticles (40- and 80-nm AgNPs) were compared to enhance the scattering signal of the immunotargeted plasmonic nanoprobe for the 3D EDF-SRM system. The standard TNF-α was immunotargeted at a single-molecule level and was quantitatively analyzed by measuring the scattering signals of 80-nm AgNPs on an array chip with gold-nanostages (GNSs) with 100-nm spot diameters. The localization precision in the 80-nm AgNP immunotag on the GNS narrowed to ~ 9.5 nm after applying the least-cubic algorithm. The developed nanosensor exhibited a detection limit of 65 zM (1.14 ag/mL; S/N = 3) with a wide dynamic detection range of 65 zM−2.08 pM (1.14 ag/mL−36.4 pg/mL; R = 0.9921). These values are 20−33,400,000 times lower than detection limits obtained using previous methods. In addition, a recovery greater than 98% was achieved by spiking standard TNF-α into human serum samples. This method should facilitate simultaneous improvements in immunotargeting precision and ultra-high sensitive detection of various disease-related target protein molecules at a single-molecule level.
Soyeong Ju; Seungah Lee; Suresh Kumar Chakkarapani; Kyungsoo Kim; Hyunung Yu; Seong Ho Kang. One-Shot Dual-Code Immunotargeting for Ultra-Sensitive Tumor Necrosis Factor-α Nanosensors by 3D Enhanced Dark-Field Super-Resolution Microscopy. Analytical Chemistry 2018, 90, 5100 -5107.
AMA StyleSoyeong Ju, Seungah Lee, Suresh Kumar Chakkarapani, Kyungsoo Kim, Hyunung Yu, Seong Ho Kang. One-Shot Dual-Code Immunotargeting for Ultra-Sensitive Tumor Necrosis Factor-α Nanosensors by 3D Enhanced Dark-Field Super-Resolution Microscopy. Analytical Chemistry. 2018; 90 (8):5100-5107.
Chicago/Turabian StyleSoyeong Ju; Seungah Lee; Suresh Kumar Chakkarapani; Kyungsoo Kim; Hyunung Yu; Seong Ho Kang. 2018. "One-Shot Dual-Code Immunotargeting for Ultra-Sensitive Tumor Necrosis Factor-α Nanosensors by 3D Enhanced Dark-Field Super-Resolution Microscopy." Analytical Chemistry 90, no. 8: 5100-5107.
Guenyoung Park; Suresh Kumar Chakkarapani; Soyeong Ju; Sujin Ahn; Seong Ho Kang. Super-resolution morphological dissemination of intercalating dye in single DNA molecules via binding activated localization microscopy. Chinese Chemical Letters 2018, 29, 505 -508.
AMA StyleGuenyoung Park, Suresh Kumar Chakkarapani, Soyeong Ju, Sujin Ahn, Seong Ho Kang. Super-resolution morphological dissemination of intercalating dye in single DNA molecules via binding activated localization microscopy. Chinese Chemical Letters. 2018; 29 (3):505-508.
Chicago/Turabian StyleGuenyoung Park; Suresh Kumar Chakkarapani; Soyeong Ju; Sujin Ahn; Seong Ho Kang. 2018. "Super-resolution morphological dissemination of intercalating dye in single DNA molecules via binding activated localization microscopy." Chinese Chemical Letters 29, no. 3: 505-508.
Human apolipoprotein E (ApoE) is associated with high cholesterol levels, coronary artery disease, and especially Alzheimer's disease. In this study, we developed an ApoE genotyping and one-step multiplex polymerase chain reaction (PCR) based-capillary electrophoresis (CE) method for the enhanced diagnosis of Alzheimer's. The primer mixture of ApoE genes enabled the performance of direct one-step multiplex PCR from whole blood without DNA purification. The combination of direct ApoE genotyping and one-step multiplex PCR minimized the risk of DNA loss or contamination due to the process of DNA purification. All amplified PCR products with different DNA lengths (112-, 253-, 308-, 444-, and 514-bp DNA) of the ApoE genes were analyzed within 2min by an extended voltage programming (VP)-based CE under the optimal conditions. The extended VP-based CE method was at least 120-180 times faster than conventional slab gel electrophoresis methods In particular, all amplified DNA fragments were detected in less than 10 PCR cycles using a laser-induced fluorescence detector. The detection limits of the ApoE genes were 6.4-62.0pM, which were approximately 100-100,000 times more sensitive than previous Alzheimer's diagnosis methods In addition, the combined one-step multiplex PCR and extended VP-based CE method was also successfully applied to the analysis of ApoE genotypes in Alzheimer's patients and normal samples and confirmed the distribution probability of allele frequencies. This combination of direct one-step multiplex PCR and an extended VP-based CE method should increase the diagnostic reliability of Alzheimer's with high sensitivity and short analysis time even with direct use of whole blood.
Nain Woo; Su-Kang Kim; Yucheng Sun; Seong Ho Kang. Enhanced capillary electrophoretic screening of Alzheimer based on direct apolipoprotein E genotyping and one-step multiplex PCR. Journal of Chromatography B 2018, 1072, 290 -299.
AMA StyleNain Woo, Su-Kang Kim, Yucheng Sun, Seong Ho Kang. Enhanced capillary electrophoretic screening of Alzheimer based on direct apolipoprotein E genotyping and one-step multiplex PCR. Journal of Chromatography B. 2018; 1072 ():290-299.
Chicago/Turabian StyleNain Woo; Su-Kang Kim; Yucheng Sun; Seong Ho Kang. 2018. "Enhanced capillary electrophoretic screening of Alzheimer based on direct apolipoprotein E genotyping and one-step multiplex PCR." Journal of Chromatography B 1072, no. : 290-299.
A fluorescence-free real-time three-dimensional (3D) super-localization method for the analysis of 3D structure of organelles (e.g., mitochondria-associated endoplasm reticulum [mito-ER] contacts) in live single cells under physiological conditions was developed with dual-wavelength enhanced dark-field microscopy. The method was applied to live single cells under physiological conditions to analyze the complex 3D mito-ER contact region by choosing an optimum nanotag with distinct scattering properties. Combining dual-view with enhanced dark-field microscopy provided concurrent images of different scattering wavelengths of nanotag-labeled mitochondria and ER. The reconstructed super-localized images resolved controversy over the distance between the intracellular organelles at functional contacts. The distance between mitochondria and ER was measured to be 45 nm, which was ~ 50% greater than in a previous report using electron microscopic tomography, and was a better fit for the likely features of these structures. These results indicate that this method was a reliable and convenient approach for investigating the 3D structure of organelles, such as mito-ER contacts in live single cells, and provided accurate information under physiological conditions.
Suresh Kumar Chakkarapani; Peng Zhang; Seong Ho Kang. 3D super-localization of intracellular organelle contacts at live single cell by dual-wavelength synchronized fluorescence-free imaging. Analytical and Bioanalytical Chemistry 2017, 410, 1551 -1560.
AMA StyleSuresh Kumar Chakkarapani, Peng Zhang, Seong Ho Kang. 3D super-localization of intracellular organelle contacts at live single cell by dual-wavelength synchronized fluorescence-free imaging. Analytical and Bioanalytical Chemistry. 2017; 410 (5):1551-1560.
Chicago/Turabian StyleSuresh Kumar Chakkarapani; Peng Zhang; Seong Ho Kang. 2017. "3D super-localization of intracellular organelle contacts at live single cell by dual-wavelength synchronized fluorescence-free imaging." Analytical and Bioanalytical Chemistry 410, no. 5: 1551-1560.