Geometrically-controlled evaporation-driven deposition of conductive carbon nanotube patterns on inclined surfaces.

Controllable accumulation of carbon nanotubes in self-assembly techniques is of critical importance in smart patterning and printed electronics. This study investigates how inclining the substrate and inhibiting the droplet spreading by sharp solid edges can affect the droplet contact angle and pinning time to improve the electrical conductivity and uniformity of the deposited patterns. Rectangular and circular pedestals were employed to investigate the effect of geometry on the deposition characteristics and to incorporate the gravitational effect by varying the substrate inclination angle. The results indicate that confining the droplet contact line to remain pinned to the pedestal edge can significantly alter the width, uniformity, and precision of the deposited patterns. These improvements correspond to the enhancement of the droplet pinning time (due to the edge effect) and to the further increase of the local evaporation rate near the contact line (due to the droplet elevation). By conducting experiments on different rectangular pedestals with varying solid-liquid interfacial areas and comparing their deposition characteristics, a rectangular pedestal with specific dimensions is selected in terms of pattern consistency and material usage efficiency. It is also shown that higher inclination angles further increase the deposited line accumulation density. Combining confinement and inclination techniques yields promising deposited patterns with high consistency and low resistivity, ranging from 8.75 kΩ mm-1 to a minimum of 0.63 kΩ mm-1 for a 3 × 6 mm2 rectangular pedestal.

Effect of surfactant concentration on the evaporation-driven deposition of carbon nanotubes: from coffee-ring effect to strain sensing.

Carbon nanotubes (CNTs) as electrically conductive materials are of great importance in the fabrication of flexible electronic devices and wearable sensors. In this regard, the evaporation-driven self-assembly of CNTs has attracted increasing attention. CNT-based applications are mostly concerned with the alignment of CNTs and the density of CNT films. In the present work, we focus on the latter by trying to achieve an optimal evaporation-driven deposition with the densest CNT ring. Although surfactants are used for effective dispersion and colloidal stabilization of CNTs in the aqueous phase, their excessive usage induces Marangoni eddies in the evaporating sessile droplets, leading to poor ring depositions. Thus, there is an optimum surfactant concentration that contributes to CNTs deagglomeration and results in the densest ring-like deposition with relatively high thickness. We report that this optimum concentration for sodium dodecyl sulfate (SDS) as a surfactant can be approximately considered as much as the concentration of multi-walled carbon nanotubes (MWCNTs) as the colloidal nanoparticles. Optimal depositions show the lowest electrical resistances for each CNT concentration, making them suitable for electronic applications. We also propose the multiple depositions method in which a new droplet is printed after the complete evaporation of the previous droplet. This method can lead to denser rings with a higher conductivity using lower concentrations of CNTs. Lastly, we fabricate strain sensors based on the optimal evaporation-driven deposition of CNTs which show higher gauge factors than the commercial strain gauges, corroborating the applicability of our method.

Effect of Particle Concentration on Surfactant-Induced Alteration of the Contact Line Deposition in Evaporating Sessile Droplets.

Controlling and suppressing the so-called "coffee-ring effect" (CRE) is an issue of cardinal importance and intense interest in many industries and scientific fields. Here, the combined effect of the particle and surfactant concentration on the CRE is investigated by gradually adding Triton X-100 surfactant to colloidal suspensions of SiO2 nanoparticles in ethanol for various particle concentrations. First, the effect of particle concentration on the contact line dynamics during the evaporation of a sessile droplet is investigated. It is shown that increasing the particle concentration leads to an increase in pinning time and ring width, whereas the droplet's initial and dynamic contact angle remains unchanged. Afterward, the effect of different concentrations of surfactant is studied for different particle concentrations. It is concluded that the surfactant concentration at which the CRE is suppressed is dependent on the initial particle concentration of the colloid, and it increases as the particle concentration increases. Furthermore, as adding surfactant with a concentration lower than this critical concentration results in an unsuppressed CRE, it is shown that surpassing this concentration will result in a depletion of particles in the contact line. Moreover, it is demonstrated that this critical surfactant concentration has no significant effect on the droplet's geometry and the total evaporation time.

Methylation status of interleukin-6 gene promoter in patients with Behçet's disease / Estatus de la metilación del promotor del gen interleucina-6 en pacientes con síndrome de Behçet

BACKGROUND: IL-6 mRNA expression is significantly high in many autoimmune diseases such as Behçet's disease; this is often related with more aggressive phenotypes. Nevertheless, the essential molecular process for its high expression has not been completely realized. The aim of this study was undertaken to estimate the gene copy number variation and promoter methylation to IL-6's high expression. METHODS: This study was performed on 51 patients and 61 healthy controls. Initially, DNA and RNA were extracted from all specimens. Promoter methylation levels of IL-6 were evaluated by MeDIP-qPCR technique. Also, IL-6 gene expression was measured by Real-time PCR. After that, we evaluated the relationship between gene expression and methylation, as well as their relationship with clinical specification. RESULTS: As we expected, the expression level of IL-6 gene increased significantly in the patient group compared to the healthy subjects. Also, the relative promoter methylation level of the IL-6 mRNA was significantly lower in patient group compared to healthy group (p < 0.001). DISCUSSION: We disclosed that the promoter hypomethylation may be considered as one of the main defects for IL-6 mRNA high expression in patients with Behçet's disease

ANTECEDENTES: La expresión de ARNm de IL-6 es significativamente elevada en muchas enfermedades autoinmunes, tales como el síndrome de Behçet, y ello se relaciona a menudo con fenotipos más agresivos. Sin embargo, no se ha comprendido plenamente el proceso molecular esencial para esta expresión elevada. El objetivo de este estudio fue la estimación de la variación del número de copias del gen, y la metilación del promotor de la expresión elevada de IL-6. MÉTODOS: Este estudio se realizó en 51 pacientes y 61 controles sanos. Al inicio, se extrajo ADN y ARN de todas las muestras. Se evaluaron los niveles de metilación del promotor de IL-6 mediante la técnica MeDIP-qPCR. También se midió la expresión del gen IL-6 mediante PCR a tiempo real. Tras ello, evaluamos la relación entre la expresión del gen y la metilación, así como su relación con la especificación clínica. RESULTADOS: Según lo previsto, el nivel de expresión del gen IL-6 se incrementó significativamente en el grupo de pacientes, con respecto a los sujetos sanos. También encontramos que el nivel relativo de metilación del promotor de ARNm de IL-6 fue considerablemente menor en el grupo de pacientes, con respecto al grupo sano (p < 0,001). DISCUSIÓN: Concluimos que la hipometilación del promotor puede considerarse uno de los defectos principales de la expresión elevada de ARNm de IL-6, en los pacientes con síndrome de Behçet

Evaluation of DNA methylation status of toll-like receptors 2 and 4 promoters in Behcet's disease.

BACKGROUND: Altered innate immune function plays an important role in the initiation of inflammatory response in Behcet's disease (BD). Toll-like receptors (TLRs) are the master regulators of the innate immune system. Because the role of TLRs remains unknown in the pathogenesis of BD, the present study aimed to evaluate the expression levels and methylation status of the TLR2 and TLR4 promoters in patients with BD. METHODS: In the present study, Iranian Azeri BD patients (n = 47) with an active (n = 22) and inactive (n = 25) period, and healthy controls (n = 61), were matched according to age, sex and ethnicity. TLR2 and TLR4 genes promoter CpG islands were predicted with the Eukaryotic Promoter Database (https://epd.vital-it.ch). Methylated DNA immunoprecipitation (MeDIP) was conducted. RESULTS: The results showed that mRNA of TLR4 was significantly increased in the peripheral blood mononuclear cells (PBMCs) of BD patients with an active phase compared to the control group. Differences in mRNA of TLR4 between the inactive BD and control groups were not significant. Differences in TLR2 mRNA levels in the PBMCs of the active and inactive phase BD and control groups were not significant. The methylation rate of TLR4 gene promoter was significantly lower in the active and inactive BD groups compared to the control group. The difference between the active and inactive BD groups was not significant. There was no significant difference in the methylation rates of the TLR2 gene between studied groups. CONCLUSIONS: Our preliminary findings suggest that the hypomethylation of TLR4 gene may be involved in the pathogenesis of BD via increasing TLR4 expression.

Interleukin-17 mRNA expression and serum levels in Behçet's disease.

Behçet's disease (BD) was considered a T-helper 1 (Th1)-mediated autoimmune disease, but with the introduction of Th17 cells, their role in the pathogenesis of BD was also addressed. Despite studies on IL-17 in BD, the prognostic value of this cytokine in BD is unclear. The aim of this study is to determine the IL-17 mRNA expression rate and serum levels in patients with BD and its correlation with clinical manifestations and activity of BD. Forty-six BD patients in the active phase of the disease and 70 healthy controls were recruited in this study. BD activity was measured by Behçet's disease current activity form (BDCAF), Iranian Behçet's disease dynamic activity measure (IBDDAM) and total inflammatory activity index (TIAI). The IL-17 mRNA expression and serum levels were significantly higher in the BD patients compared with the healthy controls. These parameters in the BD patients aged <25 at disease onset, positive pathergy test, and positive HLA-B5 and HA-B51 were significantly higher than the healthy controls (P < 0.05). The IL-17 serum level in the patients with active uveitis was lower than the patients with in-active uveitis. There was no association between other clinical manifestations of BD and these parameters. No significant correlation was found between BDCAF and IBDDAM with IL-17 mRNA expression and serum levels. However, TIAI had a significant and negative correlation with the serum levels of IL-17.

Methylation status of interleukin-6 gene promoter in patients with Behçet's disease.

BACKGROUND: IL-6 mRNA expression is significantly high in many autoimmune diseases such as Behçet's disease; this is often related with more aggressive phenotypes. Nevertheless, the essential molecular process for its high expression has not been completely realized. The aim of this study was undertaken to estimate the gene copy number variation and promoter methylation to IL-6's high expression. METHODS: This study was performed on 51 patients and 61 healthy controls. Initially, DNA and RNA were extracted from all specimens. Promoter methylation levels of IL-6 were evaluated by MeDIP-qPCR technique. Also, IL-6 gene expression was measured by Real-time PCR. After that, we evaluated the relationship between gene expression and methylation, as well as their relationship with clinical specification. RESULTS: As we expected, the expression level of IL-6 gene increased significantly in the patient group compared to the healthy subjects. Also, the relative promoter methylation level of the IL-6 mRNA was significantly lower in patient group compared to healthy group (p<0.001). DISCUSSION: We disclosed that the promoter hypomethylation may be considered as one of the main defects for IL-6 mRNA high expression in patients with Behçet's disease.

The expression and methylation status of vitamin D receptor gene in Behcet's disease.

INTRODUCTION: Vitamin D has important roles as a natural immune modulator via regulating the expression of genes which have been implicated in the pathophysiology of autoimmune diseases. Vitamin D function and its deficiency have been linked to a wide range of metabolic disorders including disorders of calcium metabolism, malignant, cardiovascular, infectious, neuromuscular, and inflammatory diseases. Environmental factors, genetic factors, and epigenetic changes contribute to Behcet's disease (BD) development. The aim of our study was to analyze the expression level and methylation status of the vitamin D receptor (VDR) gene promoter in the peripheral blood mononuclear cells (PBMCs) of patients with BD. METHODS: In a case-control study, 48 Iranian Azeri patients with BD and 60 age-, sex- and ethnically-matched healthy controls were included. Venous blood samples were collected and PBMCs were isolated by Ficoll protocol. The DNA and RNA were subsequently extracted. Promoter methylation levels were evaluated by MeDIP-quantitative polymerase chain reaction (qPCR). The expression of VDR was evaluated by real-time PCR. RESULTS: The results of quantitative real-time PCR analysis showed that the level of VDR expression in patients with BD was significantly lower than the control group (P = .013). There was no significant difference in the level of DNA methylation in the BD and control groups (P > .05). As the results show, the expression level of VDR gene was significantly different between female and male in the patient group (P = .001). VDR gene expression was significantly higher in subjects with phlebitis. No correlation was observed between VDR gene expression rate and BD activity. CONCLUSION: VDR gene expression decreased in patients with BD. However, there is no suggestion evidence that the expression level of VDR is regulated by a unique DNA methylation mechanism. No correlation exists between VDR gene expression and BD activity.

Expression levels of miR-21, miR-146b and miR-326 as potential biomarkers in Behcet's disease.

Aim: Behcet's disease (BD) is a vasculitis. Lines of evidence suggest miRNAs as diagnostic and prognostic markers in autoimmune diseases. This study was designed to investigate the potential role of miR-21, miR-146b and miR-326 as biomarkers for diagnosis, predicting organs involvement and measuring BD activity. Patients & methods: In this cross-sectional study, the study groups consisted of 46 BD patients and 70 age- and sex-matched healthy volunteers. The expression rates of three miRNAs were determined by quantitative real-time PCR. Results: Our results demonstrated significantly lower expression of miR-21 and miR-146b and higher expression of miR-326 in BD patients. MiR-21 expression rate in patients with severe eye involvement and miR-326 expression rate in patients with uveitis and severe eye involvement were increased. Conclusion: MiR-326 expression rate can be used as a biomarker for prediction of uveitis and severe eye involvement in patients with BD.

Vitamin D Deficiency among Patients with Tuberculosis: a Cross-Sectional Study in Iranian-Azari Population.

BACKGROUND: Vitamin D deficiency or insufficiency has been conducted with increased risk for tuberculosis (TB). Despite this association, discrepancies exist among different studies in different regions. The aim of this study was to evaluate the prevalence of vitamin D deficiency and its predictors in tuberculosis among the Iranian-Azari population. MATERIALS AND METHODS: A total of 60 participants were enrolled in this study, 30 of which were newly diagnosed TB patients and 30 were healthy volunteers. At least two serum samples were collected, the first sample before the start of anti-TB treatment and the second sample 3 months after the effective treatment. RESULTS: The prevalence of vitamin D deficiency (25 patients vs. 2 healthy individuals; P<0.001) and serum levels of the vitamin D (22.66±15.17 vs. 73.03±25.6 ng/mL; P<0.001) were significantly higher in patients with TB than healthy subjects. Likewise, the prevalence of vitamin D deficiency in the extrapulmonary TB group was higher than that of the pulmonary TB, but this difference was not statistically significant (P=0 .397). Moreover, there was no significant difference between mean levels of vitamin D in patients with tuberculosis before and after treatment (P = 0.787). Linear regression analysis showed there was no significant relationship between vitamin D levels after treatment and age, gender, body site of tuberculosis, and vitamin D levels before treatment, P≥0.68. CONCLUSION: Vitamin D deficiency is higher in patients with tuberculosis than healthy individuals.

Analysis of Methylation and Expression Profile of Foxp3 Gene in Patients with Behçet's Syndrome.

Forkhead box P3 (Foxp3) gene is an important means in the Treg cells function, in both maintenances of immune tolerance and regulation of response. Epigenetic modifications of the foxp3 gene at its regulatory regions control the chromatin accessibility for the transcription factors and other transcriptional regulators in order to control Foxp3 expression. In addition, the methylation status of CpG islands within the Foxp3 promoter and regulatory elements regulate the expression of Foxp3. This study was performed to assess the role of the foxp3 gene in patients with Behçet's syndrome (BS). Venous blood samples were collected from all participants and peripheral blood mononuclear cells (PBMC) were extracted through Ficoll-Hypaque method. Genomic DNA was randomly sheared by sonication and immunoprecipitated with a monoclonal antibody. The status methylation of the foxp3 gene was estimated in 108 blood samples of active BS patients and healthy individuals (controls); using methylation DNA immunoprecipitation (MeDIP) technique. Expression analysis was carried out; using Real-time PCR. The expression of foxp3 gene in the patients' group (mean±SD: 1.79±1.12) was significantly lower than the healthy group (mean±SD: 2.73±1.33) (p<001). Also, the methylation levels of Foxp3 promoter showed that its level in patients (mean±SD: 2.3±1.16) was higher than the healthy group (mean±SD: 1.85±0.59). However, this increase was not statistically significant (p>0.05). Also, these results indicated that increasing the amount of methylation of the foxp3 gene by reducing its expression leads to an increase and intensifying of the disease. The decrease in Foxp3 expression is possibly associated with hypermethylation of the gene, and it can be considered as a risk factor for BS. Future studies may be needed to identify the capability of specific DNA methylation alterations in this syndrome.

Epigenetics and Behçet's Disease: DNA Methylation Specially Highlighted.

Behçet's disease (BD) is a multisystem inflammatory disease with unknown etiology. Although evidence about the pathogenesis of BD is growing, the actual cause of this disease is unclear. Both genetic and epigenetic factors are claimed to play significant roles in BD. Epigenetic factors such as age, gender, smoking as well as exogenous factors like diet, infection, stress are related to the onset and clinical manifestations of BD. DNA methylation refers to a major epigenetic element which influences gene activities with catalyzing DNA using a set of DNA methyltransferases (Dnmts). DNA methylation status of many genes in patients with BD is different from that of healthy people. For example, cytoskeletal gene, Human Leukocyte Antigen (HLA) loci, Long interspersed nuclear element (LINE-1), and Arthrobacter luteus (Alu) repetitive sequences are different in the DNA methylation status in patients with BD and healthy controls. In this paper we reviewed, according to previous studies, the mechanisms of epigenetic, the epigenetic factors involved in the BD, and especially the effect of DNA methylation in the Behcet's disease. Future studies are needed to identify the capability of specific DNA methylation alterations in BD in order to predict disease manifestations, medical course, and response to treatment.

Determination of mir-155 and mir-146a expression rates and its association with expression level of TNF-α and CTLA4 genes in patients with Behcet's disease.

INTRODUCTION: MicroRNAs (miRNAs) are involved in the pathogenesis of inflammatory diseases. MiR-146 and miR-155 emerged as key regulators of the immune response. This study designed to analyze the miR-146a and miR-155 expression in patients with Behcet's disease (BD) and investigated their association with the expression of tumor necrosis factor-alpha (TNF-α) and cytotoxic T lymphocyte associated antigen-4 (CTLA-4) genes. METHODOLOGY: In a case-control study, 47 Iranian Azeri BD patients and 61 age- and sex matched healthy controls recruited to the study. Peripheral blood mononuclear cells (PBMCs) were isolated from EDTA blood tubes by Ficoll density-gradient centrifugation. Genomic DNA samples of BD and healthy controls were extracted using the rapid genomic DNA extraction method from the peripheral blood collected in tubes containing EDTA. Total RNA was extracted from the PBMCs according to the TRIzol protocol. MiR-146a, miR-155, TNF-α and CTLA-4 expression were studied using real-time PCR. RESULTS: MiR-155 and TNF-α expression was significantly increased, whilst CTLA-4 expression was significantly decreased in the PBMCs of BD patients. There was no significant difference in the miR-146a expression rate between BD patients and controls. A positive correlation between miR-155 and TNF-α expression and negative correlation between miR-155 and CTLA-4 expression were observed. No significant association was observed between the expression of miR-155, miR-146a, TNF-α and CTLA-4 genes with BD activity. MiR-155 and miR-146a expression rate were significantly higher in patients with uveitis and phlebitis, respectively. DISCUSSION AND CONCLUSION: The expression of miR-155 increased in BD and associated with upregulation of TNF-α and downregulation of CTLA-4 genes.

Hypermethylation of IL-10 gene is responsible for its low mRNA expression in Behçet's disease.

Interleukin-10 (IL-10), produced generally by monocyte, T helper type 2 (Th2), and regulatory T cells (Treg), plays a central role in controlling inflammatory responses and regulating the immune response of the IL-10 mRNA expression. It is significantly down-regulated in many autoimmune diseases such as Behçet's disease; this is mostly associated with more aggressive complications. Nevertheless, the essential molecular process for its low expression has not been completely realized. The aim of this project was attempted to estimate the gene expression, promoter methylation, and protein levels to IL-10's down-regulated expression. In this study, blood samples from 51 (4 missed) patients and 63 (2 missed) healthy controls were taken, with the mononuclear cells isolated by the Ficoll Protocol. DNA and RNA were then subsequently extracted. Promoter methylation levels were evaluated by MeDIP-qPCR. Following this, the extracted RNA was converted to cDNA using the RT-PCR method, with the expression of IL-10 later evaluated by Real-time PCR. And then, serum levels of IL-10 were measured using ELISA method. As we expected, the expression level of the IL-10 gene was seen to significantly decline in the patient group in comparison to the control. Also, the rate of promoter methylation was significantly higher in the IL-10 mRNA low expression group (patient group) compared to its high expression group (healthy group) (P < 0.001). We revealed that hypermethylation of promoter region was the principal defect for the IL-10 mRNA low expression in patients with Behçet's disease.