A vertically paired electrode for redox cycling and its application to immunoassays.

An electrochemical immunoassay based on the redox cycling method was presented using vertically paired electrodes (VPEs), which were fabricated using poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as an electrode material and parylene-C as a dielectric layer. For the application to immunoassays, different electrochemical properties of PEDOT:PSS were analyzed for the redox reaction of 3,3',5,5'-tetramethylbenzidine (TMB, the chromogenic substrate for enzyme-immunoassays) at different pH conditions, including the conductivity (σ), electron transfer rate constant (kapp), and double-layer capacitance (Cdl). The influencing factors on the sensitivity of redox cycling based on VPE based on PEDOT:PSS were analyzed for the redox reaction of TMB, such as the electrode gap and number of electrode pairs. Computer simulation was also performed for the redox cycling results based on VPEs, which had limitations in fabrication, such as VPEs with an electrode gap of less than 100 nm and more than five electrode pairs. Finally, the redox cycling based on VPE was applied to the medical diagnosis of human hepatitis-C virus (hHCV) using a commercial ELISA kit. The sensitivity of the redox cycling method for the medical diagnosis of hHCV was compared with conventional assay methods, such as TMB-based chromogenic detection, luminol-based chemiluminescence assay, and a rapid test kit (lateral flow immunoassay).

Carbon electrode obtained via pyrolysis of plasma-deposited parylene-C for electrochemical immunoassays.

In this study, parylene-C films from plasma deposition as well as thermal deposition were pyrolyzed to prepare a carbon electrode for application in electrochemical immunoassays. Plasma deposition could prepare parylene-C in a faster deposition rate and more precise control over the thickness in comparison with the conventional thermal deposition. To analyze the influence of the deposition method, the crystal and electronic structures of the pyrolyzed parylene-C films obtained via both deposition methods were compared using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. For application as a carbon electrode in immunoassays, the electrochemical properties of the pyrolyzed carbon films from two both deposition methods were analyzed, including the double layer capacitance (2.10 µF cm-2 for plasma deposition and 2.20 µF cm-2 for thermal deposition), the apparent electron transfer rate (approximately 1.1 × 10-3 cm s-1 for both methods), and the electrochemical window (approximately -1.0 ∼ 2.1 V for both methods). Finally, the applicability of the pyrolyzed carbon electrode from parylene-C was demonstrated for the diagnosis of human hepatitis-C using various amperometric methods, such as cyclic voltammetry, chronoamperometry, square-wave voltammetry and differential pulse voltammetry.

One-step immunoassay for the detection of food-poisoning related bacteria using a switching peptide.

A one-step immunoassay was developed for five types of food-poisoning-related bacteria using a switching peptide and antibodies isolated from unimmunized horse serum. The one-step immunoassay involves mixing samples and reagents in a homogeneous solution without any washing steps. In this work, a one-step immunoassay configuration was developed using isolated antibodies labelled with an organic fluorescence quencher and a switching-peptide labelled with a fluorescent dye. The fluorescence-labelled switching-peptide was bound to the antigen-binding site of the isolated antibodies before binding to the bacteria (no fluorescence signal), and the switching-peptide dissociated from the antibodies as soon as they bound to the bacteria (fluorescence signal turns on). By quantifying the generated fluorescence signal, the one-step immunoassay presented here allows microbial detection without any washing step.

Suppressing Pyroptosis Augments Post-Transplant Survival of Stem Cells and Cardiac Function Following Ischemic Injury.

The acute demise of stem cells following transplantation significantly compromises the efficacy of stem cell-based cell therapeutics for infarcted hearts. As the stem cells transplanted into the damaged heart are readily exposed to the hostile environment, it can be assumed that the acute death of the transplanted stem cells is also inflicted by the same environmental cues that caused massive death of the host cardiac cells. Pyroptosis, a highly inflammatory form of programmed cell death, has been added to the list of important cell death mechanisms in the damaged heart. However, unlike the well-established cell death mechanisms such as necrosis or apoptosis, the exact role and significance of pyroptosis in the acute death of transplanted stem cells have not been explored in depth. In the present study, we found that M1 macrophages mediate the pyroptosis in the ischemia/reperfusion (I/R) injured hearts and identified miRNA-762 as an important regulator of interleukin 1ß production and subsequent pyroptosis. Delivery of exogenous miRNA-762 prior to transplantation significantly increased the post-transplant survival of stem cells and also significantly ameliorated cardiac fibrosis and heart functions following I/R injury. Our data strongly suggest that suppressing pyroptosis can be an effective adjuvant strategy to enhance the efficacy of stem cell-based therapeutics for diseased hearts.

Bioassay-Guided Isolation of Anti-Alzheimer Active Components from the Aerial Parts of Hedyotis diffusa and Simultaneous Analysis for Marker Compounds.

Previous studies have reported that Hedyotis diffusa Willdenow extract shows various biological activities on cerebropathia, such as neuroprotection and short-term memory enhancement. However, there has been a lack of studies on the inhibitory activity on neurodegenerative diseases such as Alzheimer's disease (AD) through enzyme assays of H. diffusa. Therefore, H. diffusa extract and fractions were evaluated for their inhibitory effects through assays of enzymes related to AD, including acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), and ß-site amyloid precursor protein cleaving enzyme 1 (BACE1), and on the formation of advanced glycation end-product (AGE). In this study, ten bioactive compounds, including nine iridoid glycosides 1-9 and one flavonol glycoside 10, were isolated from the ethyl acetate and n-butanol fractions of H. diffusa using a bioassay-guided approach. Compound 10 was the strongest inhibitor of cholinesterase, BACE1, and the formation of AGEs of all isolated compounds, while compound 5 had the lowest inhibitory activity. Compounds 3, 6, and 9 exhibited better inhibitory activity than other compounds on AChE, and two pairs of diastereomeric iridoid glycoside structures (compounds 4, 8, and 6, 7) showed higher inhibitory activity than others on BChE. In the BACE1 inhibitory assay, compounds 1-3 were good inhibitors, and compound 10 showed higher inhibitory activity than quercetin, the positive control. Moreover, compounds 1 and 3 were stronger inhibitors of the formation of AGE than aminoguanidine (AMG), the positive control. In conclusion, this study is significant since it demonstrated that the potential inhibitory activity of H. diffusa on enzymes related to AD and showed the potential use for further study as a natural medicine for AD treatment on the basis of the bioactive components isolated from H. diffusa.

Planar dielectric cylindrical lens at 800 nm and the role of fabrication imperfections.

Conventional optical components have been proposed to realize high-quality line focusing with uniform intensity distribution such as cylindrical lenses, segmented wedge-arrays, or a combination of prisms and spherical mirrors. Numerous factors such as the manufacturing tolerances or the need for precise alignment of conventional lenses cause wave front aberrations that impact the performance of optical systems. These aforementioned limitations affect the uniformity of the intensity distribution and the intercept factor of lenses. Here, we experimentally demonstrate an integrable planar dielectric cylindrical lens made of titanium dioxide for uniform line focusing and discuss the sensitivity of its performance to fabrication imperfections originating from non-ideal geometrical parameters. The lens has a numerical aperture of 0.247, an intercept factor of 0.85, and an efficiency of 79% at 800 nm.

Hybridized metamaterial platform for nano-scale sensing.

Plasmonic/metamaterial sensors are being investigated for their high sensitivity, fast response time, and high accuracy. We propose, characterize and experimentally realize subwavelength bilayer metamaterial sensors operating in the near-infrared domain. We measure the figure-of-merit (FOM) and the bulk sensitivity (S) of the two fundamental hybridized modes and demonstrate both numerically and experimentally that the magnetic dipolar mode, degenerate with the electric quadrupolar mode, has higher sensitivity to a variation of the refractive index compared to the electric dipolar mode. In addition, the hybridized system exhibits a four fold increase in the FOM compared to a standard dipolar plasmonic system.

Integrated metaphotonics: symmetries and confined excitation of LSP resonances in a single metallic nanoparticle.

Using numerical simulations, we demonstrate that the dipolar plasmonic resonance of a single metallic nanoparticle inserted in the core of a dielectric waveguide can be excited with higher order photonic modes of the waveguide only if their symmetry is compatible with the charge distribution of the plasmonic mode. For the case of a symmetric waveguide, we demonstrate that this condition is only achieved if the particle is shifted from the center of the core. The simple and comprehensive analysis presented in this contribution will serve as basis for applications in integrated nanophotonic/metamaterials devices, such as optical filters, modulators and mode converters.

Genetic Characteristics of Polycythemia Vera and Essential Thrombocythemia in Korean Patients.

BACKGROUND: Despite recent advances in the investigation of myeloproliferative neoplasms (MPN), the impact of genetic heterogeneity on its molecular pathogenesis has not been fully elucidated. Thus, in this study, we aim to characterize the genetic complexity in Korean patients with polycythemia vera (PV) and essential thrombocythemia (ET). METHODS: We conducted association studies using 84 single-nucleotide polymorphisms (SNPs) in 229 patients (96 with PV and 133 with ET) and 170 controls. Further, whole-genome sequencing was performed in six patients (two with JAK2 V617F and four with wild-type JAK2), and putative somatic mutations were validated in a further 69 ET patients. Clinical and laboratory characteristics were also analyzed. RESULTS: Several germline SNPs and the 46 haplotype were significantly associated with PV and ET. Three somatic mutations in MPDZ, IQCH, and CALR genes were selected and validated. The frequency of the CALR mutation was 58.0% (40/69) in ET patients, who did not carry JAK2/MPL mutations. Moreover, compared with JAK2 V617F-positive patients, those with CALR mutations showed lower hemoglobin and hematocrit levels (P = 0.004 and P = 0.002, respectively), higher platelet counts (P =0.008), and a lower frequency of cytoreductive therapy (P = 0.014). CONCLUSION: This study was the first comprehensive investigation of the genetic characteristics of Korean patients with PV and ET. We found that somatic mutations and the 46 haplotype contribute to PV and ET pathogenesis in Korean patients.

The Effects of Tonsillectomy Education Using Smartphone Text Message for Mothers and Children Undergoing Tonsillectomy: A Randomized Controlled Trial.

BACKGROUND: Tonsillectomy is the most common type of surgical procedure performed in preschool children. Due to short period of hospitalization, mothers are expected to manage their children's care at home. However, they are rarely provided with sufficient information about postoperative management. This study aims to determine the effectiveness of providing caregivers with information on tonsillectomy care by smartphone text messaging in increasing their mothers' knowledge, reducing the anxiety, and improving the sick-role behavior of pediatric tonsillectomy patients. MATERIALS AND METHODS: A sample of 61 pediatric patients and their mothers was recruited. Participants were randomly assigned into either the experimental group (n = 27) or the control group (n = 34). The control group was given information about the tonsillectomy by conventional textual and verbal means, whereas the experimental group received the same information in the form of 10 text messages during the period from hospitalization to their first follow-up visits. RESULTS: Results of mixed design, two-way analysis of variance indicated significant interaction effects between time points and groups for mothers' knowledge (F = 4.26, p = 0.043) and children's anxiety (F = 3.32; p = 0.037). Thus, the results do support the effectiveness of tonsillectomy education using smartphone text messaging in increasing mothers' knowledge and reducing children's anxiety. CONCLUSIONS: These results can be applied to preoperative and postoperative interventions for children not only for tonsillectomy but also for many other operations. The development of various educational programs using smartphone text messaging for postoperative patient management would also be valuable.

Regulation of mitochondrial morphology by positive feedback interaction between PKCδ and Drp1 in vascular smooth muscle cell.

Dynamin-related protein-1 (Drp1) plays a critical role in mitochondrial fission which allows cell proliferation and Mdivi-1, a specific small molecule Drp1 inhibitor, is revealed to attenuate proliferation. However, few molecular mechanisms-related to Drp1 under stimulus for restenosis or atherosclerosis have been investigated in vascular smooth muscle cells (vSMCs). Therefore, we hypothesized that Drp1 inhibition can prevent vascular restenosis and investigated its regulatory mechanism. Angiotensin II (Ang II) or hydrogen peroxide (H2 O2 )-induced proliferation and migration in SMCs were attenuated by down-regulation of Drp1 Ser 616 phosphorylation, which was demonstrated by in vitro assays for migration and proliferation. Excessive amounts of ROS production and changes in mitochondrial membrane potential were prevented by Drp1 inhibition under Ang II and H2 O2 . Under the Ang II stimulation, activated Drp1 interacted with PKCδ and then activated MEK1/2-ERK1/2 signaling cascade and MMP2, but not MMP9. Furthermore, in ex vivo aortic ring assay, inhibition of the Drp1 had significant anti-proliferative and -migration effects for vSMCs. A formation of vascular neointima in response to a rat carotid artery balloon injury was prevented by Drp1 inhibition, which shows a beneficial effect of Drp1 regulation in the pathologic vascular condition. Drp1-mediated SMC proliferation and migration can be prevented by mitochondrial division inhibitor (Mdivi-1) in in vitro, ex vivo and in vivo, and these results suggest the possibility that Drp1 can be a new therapeutic target for restenosis or atherosclerosis.

MicroRNA-29b inhibits migration and proliferation of vascular smooth muscle cells in neointimal formation.

The proliferation and migration of smooth muscle cells (SMCs) are considered to be key steps in the progression of atherosclerosis and restenosis. Certain stimuli, such as, interleukin-3 (IL-3) are known to stimulate proliferation and migration in vascular diseases. Meanwhile, microRNAs (miRs) have been revealed as critical modulators of various diseases in which miR-29b is known to regulate cell growth by targeting Mcl-1 and MMP2. However, roles of miR-29b in vascular smooth muscle cells remain almost unknown. We hypothesized that miR-29b may control the proliferation and migration processes induced by IL-3 stimulation by inhibiting its own specific targets in SMCs. MiR-29b significantly suppressed the proliferation and migration of SMCs through the inhibition of the signaling pathway related to Mcl-1 and MMP2. We also found that miR-29b expression levels significantly declined in balloon-injured rat carotid arteries and that the overexpression of miR-29b by local oligonucleotide delivery can inhibit neointimal formation. Consistent with the critical role of miR-29b in vitro, we observed down-regulated expression levels of Mcl-1 and MMP2 from the neointimal region. These results indicate that miR-29b suppressed the proliferation and migration of SMCs, possibly through the inhibition of Mcl-1 and MMP2, and suggest that miR-29b may serve as a useful therapeutic tool to treat cardiovascular diseases such as, atherosclerosis and restenosis.

ROS-mediated bidirectional regulation of miRNA results in distinct pathologic heart conditions.

Under distinct pathological heart conditions, the expression of a single miRNA can display completely opposite patterns. However, the mechanism underlying the bidirectional regulation of a single miRNA and the clinical implications of this regulation remain largely unknown. To address this issue, we examined the regulation of miR-1, one of the most abundant miRNAs in the heart, during cardiac hypertrophy and ischemia/reperfusion (I/R). Our data indicated that different magnitudes and chronicities of ROS levels in cardiomyocytes resulted in differential expression of miR-1, subsequently altering the expression of myocardin. In animal models, the administration of a miR-1 mimic attenuated cardiac hypertrophy by suppressing the transverse aortic constriction-induced increase in myocardin expression, whereas the administration of anti-miR-1 ameliorated I/R-induced cardiac apoptosis and deterioration of heart function. Our findings indicated that a pathologic stimulus such as ROS can bidirectionally alter the expression of miRNA to contribute to the development of pathological conditions exhibiting distinct phenotypes and that the meticulous adjustment of the pathological miRNA levels is required to improve clinical outcomes.

Near-zero pretilt alignment of liquid crystals using polyimide films doped with UV-curable polymer.

We propose an alignment method for the near-zero pretilt angle of liquid crystals (LCs) using polyimide films doped with a UV-curable polymer. The near-zero pretilt angle can be obtained by UV curing of reactive mesogen monomers mixed with planar alignment material while a vertical electric field is applied to an LC cell assembled after the rubbing process. We demonstrated that the pretilt angle can be decreased from 2.390° to 0.082° by employing the proposed method.

Elimination of image flicker in a fringe-field switching liquid crystal display by applying a bipolar voltage wave.

Recently, low-frequency driving of liquid crystal display (LCD) panels to minimize power consumption has drawn much attention. In the case in which an LCD panel is driven by a fringe-field at a low frequency, the image flickering phenomenon occurs when the sign of the applied electric field is reversed. We investigated image flickering induced by the flexoelectric effect in a fringe-field switching (FFS) liquid crystal cell in terms of the transmittance difference between frames and the ripple phenomenon. Experimental results show that image flicker due to transmittance difference can be eliminated completely and that the ripple phenomena can be reduced significantly by applying a bipolar voltage wave to the FFS cell.

PLCδ1 protein rescues ischemia-reperfused heart by the regulation of calcium homeostasis.

Myocardial Ca(2+) overload induced by ischemia/reperfusion (I/R) is a major element of myocardial dysfunction in heart failure. Phospholipase C (PLC) plays important roles in the regulation of the phosphoinositol pathway and Ca(2+) homeostasis in various types of cells. Here, we investigated the protective role of PLCδ1 against myocardial I/R injury through the regulation of Ca(2+) homeostasis. To investigate its role, PLCδ1 was fused to Hph1, a cell-permeable protein transduction domain (PTD), and treated into rat neonatal cardiomyocytes and rat hearts under respective hypoxia-reoxygenation (H/R) and ischemia-reperfusion conditions. Treatment with Hph1-PLCδ1 significantly inhibited intracellular Ca(2+) overload, reactive oxygen species generation, mitochondrial permeability transition pore opening, and mitochondrial membrane potential elevation in H/R neonatal cardiomyocytes, resulting in the inhibition of apoptosis. Intravenous injections of Hph1-PLCδ1 in rats with I/R-injured myocardium caused significant reductions in infarct size and apoptosis and also improved systolic and diastolic cardiac functioning. Furthermore, a small ions profile obtained using time-of-flight secondary ion mass spectrometry showed that treatment with Hph1-PLCδ1 leads to significant recovery of calcium-related ions toward normal levels in I/R-injured myocardium. These results suggest that Hph1-PLCδ1 may manifest as a promising cardioprotective drug due to its inhibition of the mitochondrial apoptotic pathway in cells suffering from I/R injury.

Suppression of miR-181a attenuates H2O2-induced death of mesenchymal stem cells by maintaining hexokinase II expression.

BACKGROUND: Low survival rate of transplanted cells compromises the efficacy of cell therapy. Hexokinase II (HKII) is known to have anti-apoptotic activity through its interaction with mitochondria. The objective was to identify miRNAs targeting HKII and investigate whether miRNA-mediated modulation of HKII could improve the survival of mesenchymal stem cells (MSCs) exposed to H2O2. The expression of HKII in MSCs exposed to H2O2 was evaluated, and HKII-targeting miRNA was screened based on miRNA-target prediction databases. The effect of H2O2 on the expression of the selected HKII-targeting miRNA was examined and the effect of modulation of the selected HKII-targeting miRNA using anti-miRNA on H2O2-induced apoptosis of MSC was evaluated. RESULTS: H2O2 (600 µM) induced cell death of MSCs and decreased mitochondrial HKII expression. We have identified miR-181a as a HKII-targeting miRNA and H2O2 increased the expression of miR-181a in MSCs. Delivery of anti-miR-181a, which neutralizes endogenous miR-181a, significantly attenuated H2O2-induced decrease of HKII expression and disruption of mitochondrial membrane potential, improving the survival of MSCs exposed to H2O2. CONCLUSIONS: These findings suggest that H2O2-induced up-regulation of miR-181a contributes to the cell death of MSCs by down-regulating HKII. Neutralizing miR-181a can be an effective way to prime MSCs for transplantation into ischemic tissues.

MicroRNA-365 inhibits the proliferation of vascular smooth muscle cells by targeting cyclin D1.

Abnormal proliferation of vascular smooth muscle cells (VSMCs) is a common feature of disease progression in atherosclerosis. Cell proliferation is regulated by cell cycle regulatory proteins. MicroRNAs (miR) have been reported to act as important gene regulators and play essential roles in the proliferation and migration of VSMCs in a cardiovascular disease. However, the roles and mechanisms of miRs in VSMCs and neointimal formation are far from being fully understood. In this study, cell cycle-specific cyclin D1 was found to be a potential target of miR-365 by direct binding. Through an in vitro experiment, we showed that exogenous miR-365 overexpression reduced VSMC proliferation and proliferating cell nuclear antigen (PCNA) expression, while miR-365 was observed to block G1/S transition in platelet-derived growth factor-bb (PDGF-bb)-induced VSMCs. In addition, the proliferation of VSMCs by various stimuli, including PDGF-bb, angiotensin II (Ang II), and serum, led to the downregulation of miR-365 expression levels. The expression of miR-365 was confirmed in balloon-injured carotid arteries. Taken together, our results suggest an anti-proliferative role for miR-365 in VSMC proliferation, at least partly via modulating the expression of cyclin D1. Therefore, miR-365 may influence neointimal formation in atherosclerosis patients.

A colorimetric sandwich-type assay for sensitive thrombin detection based on enzyme-linked aptamer assay.

A colorimetric sandwich-type assay based on enzyme-linked aptamer assay has been developed for the fast and sensitive detection of as low as 25 fM of thrombin with high linearity. Aptamer-immobilized glass was used to capture the target analyte, whereas a second aptamer, functionalized with horseradish peroxidase (HRP), was employed for the conventional 3,5,3',5'-tetramethylbenzidine (TMB)-based colorimetric detection. Without the troublesome antibody requirement of the conventional enzyme-linked immunosorbent assay (ELISA), as low as 25 fM of thrombin could be rapidly and reproducibly detected. This assay has superior, or at least equal, recovery and accuracy to that of conventional antibody-based ELISA.

Cardiomyocytes from phorbol myristate acetate-activated mesenchymal stem cells restore electromechanical function in infarcted rat hearts.

Despite the safety and feasibility of mesenchymal stem cell (MSC) therapy, an optimal cell type has not yet emerged in terms of electromechanical integration in infarcted myocardium. We found that poor to moderate survival benefits of MSC-implanted rats were caused by incomplete electromechanical integration induced by tissue heterogeneity between myocytes and engrafted MSCs in the infarcted myocardium. Here, we report the development of cardiogenic cells from rat MSCs activated by phorbol myristate acetate, a PKC activator, that exhibited high expressions of cardiac-specific markers and Ca(2+) homeostasis-related proteins and showed adrenergic receptor signaling by norepinephrine. Histological analysis showed high connexin 43 coupling, few inflammatory cells, and low fibrotic markers in myocardium implanted with these phorbol myristate acetate-activated MSCs. Infarct hearts implanted with these cells exhibited restoration of conduction velocity through decreased tissue heterogeneity and improved myocardial contractility. These findings have major implications for the development of better cell types for electromechanical integration of cell-based treatment for infarcted myocardium.