Extremely sensitive and wide-range silver ion detection via assessing the integrated surface potential of a DNA-capped gold nanoparticle

Lee, Dongtak,Lee, Hyungbeen,Lee, Gyudo,Kim, Insu,Lee, Sang Won,Kim, Woong,Lee, Sang Woo,Lee, Jeong Hoon,Park, Jinsung,Yoon, Dae Sung IOP 2019 Nanotechnology Vol.30 No.8

<P>With the rapid development of nanotechnology and its associated waste stream, public concern is growing over the potential toxicity exposure to heavy metal ions poses to the human body and the environment. Herein, we report an extremely sensitive Kelvin probe force microscopy (KPFM)-based platform for detecting nanotoxic materials (e.g. Ag<SUP>+</SUP>) accomplished by probing the integrated surface potential differences of a single gold nanoparticle on which an interaction between probe DNA and target DNA occurs. This interaction can amplify the surface potential of the nanoparticle owing to the coordination bond mediated by Ag<SUP>+</SUP> (cytosine–Ag<SUP>+</SUP>–cytosine base pairs). Interestingly, compared with conventional methods, this platform is capable of extremely sensitive Ag<SUP>+</SUP> detection (∼1 fM) in a remarkably wide-range (1 fM to 1 <I>μ</I>M). Furthermore, this platform enables Ag<SUP>+</SUP> detection in a practical sample (general drinking water), and this KPFM-based technique may have the potential to detect other toxic heavy metal ions and single nucleotide polymorphisms by designing specific DNA sequences.</P>

A simple and disposable carbon adhesive tape-based NO₂ gas sensor

Lee, Sang Won,Lee, Wonseok,Lee, Dongtak,Choi, Yeseong,Kim, Woong,Park, Jinsung,Lee, Jeong Hoon,Lee, Gyudo,Yoon, Dae Sung Elsevier 2018 Sensors and actuators. B Chemical Vol.266 No.-

<P><B>Abstract</B></P> <P>Nitrogen dioxide (NO<SUB>2</SUB>) is one of the toxic gas that causes debilitating disease in the respiratory system. Due to imprudent industrial development, the need for a facile and sensitive gas detection has been grown. Here, we develop a simple and disposable NO<SUB>2</SUB> gas sensor employing carbon adhesive tape (CAT) as the gas detection element. The CAT developed in this study contained a large amount of carbon black material to adsorb NO<SUB>2</SUB> gas molecules. Experiments revealed that the gas molecules were bound rapidly to the CAT sensor (<3 min). The chemical and physical characteristics of the CAT were investigated by thermal gravimetric analysis, X-ray photoelectron spectroscopy, and scanning electron microscopy. With increases of bound NO<SUB>2</SUB> gas molecules, electrical conductance was augmented. Analytical sensitivity of the CAT-based gas sensor was estimated to be 5 ppm, lower than the concentration generally considered as a minimum concentration to cause harm to people. In addition, we tested such CAT sensor for detecting NO<SUB>x</SUB> from car exhaust, suggesting the possibility of its practical application. Taken together, our results indicate that CAT-based gas sensor developed in this study is applicable as a robust, facile, and disposable NO<SUB>2</SUB> gas sensing platform.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CAT-based gas sensor is applicable as a robust, facile, and disposable NO<SUB>2</SUB> gas sensing platform. </LI> <LI> Electrical conductance of CAT chip is increased depending on the exposure time (0–10 min) and concentration (0–100 ppm) of NO<SUB>2</SUB> gas. </LI> <LI> Detection time of NO<SUB>2</SUB> gas is less than 3 min with enough sensitivity (∼5 ppm) which is lower than the concentration generally considered as a minimum concentration (10 ppm) to cause harm to human. </LI> <LI> CAT chip can detect NO<SUB>2</SUB> gas from the car exhausts such as gasoline and diesel regardless of humidity (H<SUB>2</SUB>O), carbon dioxide (CO<SUB>2</SUB>), nitrogen (N<SUB>2</SUB>) and dust. </LI> </UL> </P>

Microwave-induced formation of oligomeric amyloid aggregates

Lee, Wonseok,Choi, Yeseong,Lee, Sang Won,Kim, Insu,Lee, Dongtak,Hong, Yoochan,Lee, Gyudo,Yoon, Dae Sung IOP 2018 Nanotechnology Vol.29 No.34

<P>Amyloid aggregates have emerged as a significant hallmark of neurodegenerative diseases such as Alzheimer’s and Parkinson’s diseases. Although it has been recently reported that microwave heating induces amyloid aggregation compared with conventional heating methods, the mechanism of amyloid aggregate induction has remained unclear. In this study, we investigated the formation of oligomeric amyloid aggregates (OAAs) by microwave irradiation at microscale volumes of solution. Microwave irradiation of protein monomer solution triggered rapid formation of OAAs within 7 min. We characterized the formation of OAAs using atomic force microscopy, thioflavin T fluorescent assay and circular dichroism. In the microwave system, we also investigated the inhibitory effect on the formation of amyloid aggregates by L-ascorbic acid as well as enhanced amyloid aggregation by silver nanomaterials such as nanoparticles and nanowires. We believe that microwave technology has the potential to facilitate the study of amyloid aggregation in the presence of chemical agents or nanomaterials.</P>

Low-Powered pH-Stable Nano-electrokinetically Enhanced Lateral Flow Assay for COVID-19 Antigen Test

Kim Kang Hyeon,유용경,Lee Na Eun,Lee Junwoo,Kim Cheonjung,Lee Seungmin,Kim Jinhwan,Park Seong Jun,Lee Dongtak,이상원,Kim Hyungseok,허돈,Yoon Dae Sung,Lee Jeong Hoon 한국바이오칩학회 2023 BioChip Journal Vol.17 No.3

Lateral fl ow assay (LFA) is a popular diagnostic system used in point-of-care testing (POCT) due to its low cost and portability. However, LFA has limited sensitivity and detection limits, making it challenging to detect low virus titers. Preconcentration through nano-electrokinetic (NEK) techniques have been proposed as a promising solution to improve the sensitivity of LFA. Nevertheless, the acidic conditions used in NEK operations may reduce the specifi city and sensitivity of LFA immunoassays. To address these limitations, an integrated LFA kit, the NEK-enhanced LFA (PcNEK–LFA), has been introduced. This kit features a pH-controlled structure designed to facilitate sample preconcentration. Biomarkers and AuNPs are electrokinetically preconcentrated in the PcNEK–LFA platform to increase the concentration of the test line and Ag–Ab binding events, resulting in enhanced performance. The pH-controlled PcNEK–LFA platform was evaluated using salivary human chorionic gonadotropin beta (β-hCG) and COVID-19 Ag samples, achieving a preconcentrating factor of approximately 10 and a sensitivity enhancement of 55.42%, and a preconcentrating factor greater than 10, respectively. The pH-controlled PcNEK–LFA platform provides an eff ective solution to overcome the limitations of LFA for POCT. In addition, it improves its sensitivity and detection limit, signifi cantly enhancing the accuracy and reliability of POCT, particularly for COVID-19 screening tests. As a result, this platform may play a pivotal role in addressing current and future healthcare challenges, facilitating rapid diagnosis and treatment of infectious diseases.

Matricellular Protein CCN5 Reverses Established Cardiac Fibrosis

Jeong, Dongtak,Lee, Min-Ah,Li, Yan,Yang, Dong Kwon,Kho, Changwon,Oh, Jae Gyun,Hong, Gyeongdeok,Lee, Ahyoung,Song, Min Ho,LaRocca, Thomas J.,Chen, Jiqiu,Liang, Lifan,Mitsuyama, Shinichi,D'Escamard, Val American College of Cardiology 2016 Journal of the American College of Cardiology Vol.67 No.13

<P><B>Abstract</B></P><P><B>Background</B></P><P>Cardiac fibrosis (CF) is associated with increased ventricular stiffness and diastolic dysfunction and is an independent predictor of long-term clinical outcomes of patients with heart failure (HF). We previously showed that the matricellular CCN5 protein is cardioprotective via its ability to inhibit CF and preserve cardiac contractility.</P><P><B>Objectives</B></P><P>This study examined the role of CCN5 in human heart failure and tested whether CCN5 can reverse established CF in an experimental model of HF induced by pressure overload.</P><P><B>Methods</B></P><P>Human hearts were obtained from patients with end-stage heart failure. Extensive CF was induced by applying transverse aortic constriction for 8 weeks, which was followed by adeno-associated virus-mediated transfer of CCN5 to the heart. Eight weeks following gene transfer, cellular and molecular effects were examined.</P><P><B>Results</B></P><P>Expression of CCN5 was significantly decreased in failing hearts from patients with end-stage heart failure compared to nonfailing hearts. Trichrome staining and myofibroblast content measurements revealed that the established CF had been reversed by CCN5 gene transfer. Anti-CF effects of CCN5 were associated with inhibition of the transforming growth factor beta signaling pathway. CCN5 significantly inhibited endothelial-mesenchymal transition and fibroblast-to-myofibroblast transdifferentiation, which are 2 critical processes for CF progression, both in vivo and in vitro. In addition, CCN5 induced apoptosis in myofibroblasts, but not in cardiomyocytes or fibroblasts, both in vivo and in vitro. CCN5 provoked the intrinsic apoptotic pathway specifically in myofibroblasts, which may have been due the ability of CCN5 to inhibit the activity of NFκB, an antiapoptotic molecule.</P><P><B>Conclusions</B></P><P>CCN5 can reverse established CF by inhibiting the generation of and enhancing apoptosis of myofibroblasts in the myocardium. CCN5 may provide a novel platform for the development of targeted anti-CF therapies.</P>

PICOT Inhibits Cardiac Hypertrophy and Enhances Ventricular Function and Cardiomyocyte Contractility

Jeong, Dongtak,Cha, Hyeseon,Kim, Eunyoung,Kang, Misuk,Yang, Dong Kwon,Kim, Ji Myoung,Yoon, Pyoung Oh,Oh, Jae Gyun,Bernecker, Oliver Y.,Sakata, Susumu,Thu, Le Thi,Cui, Lei,Lee, Young-Hoon,Kim, Do Han,W Grune & Stratton 2006 Circulation research Vol.99 No.3

<P>Multiple signaling pathways involving protein kinase C (PKC) have been implicated in the development of cardiac hypertrophy. We observed that a putative PKC inhibitor, PICOT (PKC-Interacting Cousin Of Thioredoxin) was upregulated in response to hypertrophic stimuli both in vitro and in vivo. This suggested that PICOT may act as an endogenous negative feedback regulator of cardiac hypertrophy through its ability to inhibit PKC activity, which is elevated during cardiac hypertrophy. Adenovirus-mediated gene transfer of PICOT completely blocked the hypertrophic response of neonatal rat cardiomyocytes to enthothelin-1 and phenylephrine, as demonstrated by cell size, sarcomere rearrangement, atrial natriuretic factor expression, and rates of protein synthesis. Transgenic mice with cardiac-specific overexpression of PICOT showed that PICOT is a potent inhibitor of cardiac hypertrophy induced by pressure overload. In addition, PICOT overexpression dramatically increased the ventricular function and cardiomyocyte contractility as measured by ejection fraction and end-systolic pressure of transgenic hearts and peak shortening of isolated cardiomyocytes, respectively. Intracellular Ca(2+) handing analysis revealed that increases in myofilament Ca(2+) responsiveness, together with increased rate of sarcoplasmic reticulum Ca(2+) reuptake, are associated with the enhanced contractility in PICOT-overexpressing cardiomyocytes. The inhibition of cardiac remodeling by of PICOT with a concomitant increase in ventricular function and cardiomyocyte contractility suggests that PICOT may provide an efficient modality for treatment of cardiac hypertrophy and heart failure.</P>

Selective Detection of Fibrinogen via Cell Membrane-Coated Plasmonic Nanoparticles

Insu KIM,Dongtak LEE,Dohyung KWON,Gyudo LEE,Dae Sung YOON 한국생물공학회 2018 한국생물공학회 학술대회 Vol.2018 No.4

A Highly Permselective Electrochemical Glucose Sensor Employing Cell Membrane

Insu KIM,Dohyung KWON,Dongtak LEE,Gyudo LEE,Dae Sung YOON 한국생물공학회 2018 한국생물공학회 학술대회 Vol.2018 No.4

Permselective glucose sensing with GLUT1-rich cancer cell membranes

Kim, Insu,Kwon, Dohyung,Lee, Dongtak,Lee, Gyudo,Yoon, Dae Sung Elsevier 2019 Biosensors & bioelectronics Vol.135 No.-

<P><B>Abstract</B></P> <P>Enzymatic blood glucose detection with selectivity is one of the most important conundrums, because human blood contains many components that can hinder enzyme-substrate reactions. Meanwhile, cancer cells express much higher levels of glucose transporter-1 on their cell membrane to selectively and excessively uptake more α-D-glucose than do normal cells. Inspired by such cellular permselectivity for glucose, herein we significantly improved the selectivity of a glucose sensor by using a breast cancer cell membrane (BCCM). The BCCM was extracted from MDA-MB-231 cells and coated onto an enzyme-deposited electrode <I>via</I> a vesicle fusion method. We investigated BCCM-coated sensors using ATR-FTIR, SEM, AFM, and cyclic voltammetry. The exceptional permselectivity of BCCM-coated sensors was validated using glucose solutions containing various interfering molecules (<I>e.g.</I>, D-(−)-fructose, D-(+)-xylose, D-(+)-maltose, L-cysteine, L-ascorbic acid, and uric acid) and human serum (4.35–7.35 mM of glucose), implying their high potential for practical use.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The glucose transporter-rich breast cancer cell membrane (BCCM) was collected from MDA-MB-231. </LI> <LI> The BCCM layer was utilized as glucose-specific permeable membrane via glucose transporter. </LI> <LI> The BCCM-coated glucose sensors were well optimized with the thickness of BCCM layer for adequate permeability. </LI> <LI> The biosensor showed outstanding selectivity to glucose under serum and glucose-added serum. </LI> </UL> </P>

Role of SIRT1 in Modulating Acetylation of the Sarco-Endoplasmic Reticulum Ca ²⁺ -ATPase in Heart Failure

Gorski, Przemek A.,Jang, Seung Pil,Jeong, Dongtak,Lee, Ahyoung,Lee, Philyoung,Oh, Jae Gyun,Chepurko, Vadim,Yang, Dong Kwon,Kwak, Tae Hwan,Eom, Soo Hyun,Park, Zee-Yong,Yoo, Yung Joon,Kim, Do Han,Kook, Grune & Stratton 2019 Circulation research Vol.124 No.9