scholarly journals Electrochemical ELISA Protein Biosensing in Undiluted Serum Using a Polypyrrole-Based Platform

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2857 ◽  
Author(s):  
Sunil K. Arya ◽  
Pedro Estrela
Keyword(s):  
Serum Proteins ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Protein Markers ◽  
Necrosis Factor Alpha ◽  
Force Microscopy ◽  
Atomic Force ◽  
Tnf Α ◽  
Undiluted Serum

An electrochemical enzyme-linked immunosorbent assay (ELISA) biosensor platform using electrochemically prepared ~11 nm thick carboxylic functionalized popypyrrole film has been developed for bio-analyte measurement in undiluted serum. Carboxyl polypyrrole (PPy-COOH) film using 3-carboxy-pyrrol monomer onto comb-shaped gold electrode microarray (Au) was prepared via cyclic voltammetry (CV). The prepared Au/PPy-COOH was then utilized for electrochemical ELISA platform development by immobilizing analyte-specific antibodies. Tumor necrosis factor-alpha (TNF-α) was selected as a model analyte and detected in undiluted serum. For enhanced performance, the use of a polymeric alkaline phosphatase tag was investigated for the electrochemical ELISA. The developed platform was characterized at each step of fabrication using CV, electrochemical impedance spectroscopy and atomic force microscopy. The bioelectrodes exhibited linearity for TNF-α in the 100 pg/mL–100 ng/mL range when measured in spiked serum, with limit of detection of 78 pg/mL. The sensor showed insignificant signal disturbance from serum proteins and other biologically important proteins. The developed platform was found to be fast and specific and can be applicable for testing and measuring various biologically important protein markers in real samples.

scholarly journals Application of a Conducting Poly-Methionine/Gold Nanoparticles-Modified Sensor for the Electrochemical Detection of Paroxetine

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3981
Author(s):  
Saedah R. Al-Mhyawi ◽  
Riham K. Ahmed ◽  
Rasha M. El Nashar
Keyword(s):  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Electrochemical Techniques ◽  
Pharmaceutical Formulations ◽  
Differential Pulse ◽  
Force Microscopy ◽  
Atomic Force ◽  
Response Range ◽  
Pulse Voltammetry ◽  
Modified Sensor

This work demonstrates a facile electropolymerization of a dl-methionine (dl-met) conducting polymeric film on a gold nanoparticle (AuNPs)-modified glassy carbon electrode (GCE). The resulting sensor was successfully applied for the sensitive detection of paroxetine·HCl (PRX), a selective serotonin (5-HT) reuptake inhibitor (SSRIs), in its pharmaceutical formulations. The sensor was characterized morphologically using scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM) and electrochemical techniques such as differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The proposed sensor, poly (dl-met)/AuNPs-GCE, exhibited a linear response range from 5 × 10−11 to 5 × 10−8 M and from 5 × 10−8 to 1 × 10−4 M using DPV with lowest limit of detection (LOD = 1 × 10−11 M) based on (S/N = 3). The poly (dl-met)/AuNPs-GCE sensor was successfully applied for PRX determination in three different pharmaceutical formulations with percent recoveries between 96.29% and 103.40% ± SD (±0.02 and ±0.58, respectively).

scholarly journals Surface Plasmon Resonance Based on Molecularly Imprinted Polymeric Film for l-Phenylalanine Detection

Biosensors ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 21
Author(s):  
Duygu Çimen ◽  
Nilay Bereli ◽  
Adil Denizli
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Limit Of Detection ◽  
Kinetic Studies ◽  
Force Microscopy ◽  
Spr Sensor ◽  
Atomic Force ◽  
Analysis Technique ◽  
Molecular Imprinting Technology

In this study, we designed a simple, rapid, sensitive and selective surface plasmon resonance (SPR) sensor for detection of L-phenylalaine by utilizing molecular imprinting technology. l-phenylalanine imprinted and non-imprinted poly(2-hydroxyethyl methacrylate-methacryloyl-l-phenylalanine) polymeric films were synthesized onto SPR chip surfaces using ultraviolet polymerization. l-phenyalanine imprinted and non-imprinted SPR sensors were characterized by using contact angle, atomic force microscopy and ellipsometry. After characterization studies, kinetic studies were carried out in the concentration range of 5.0–400.0 μM. The limit of detection and quantification were obtained as 0.0085 and 0.0285 μM, respectively. The response time for the test including equilibration, adsorption and desorption was approximately 9 min. The selectivity studies of the l-phenylalanine imprinted SPR sensor was performed in the presence of d-phenylalanine and l-tryptophan. Validation studies were carried out via enzyme-linked immunosorbent analysis technique in order to demonstrate the applicability and superiority of the l-phenylalanine imprinted SPR sensor.

ELECTROCHEMICAL INVESTIGATION OF 2-THIOHYDANTOIN DERIVATIVES AS CORROSION INHIBITORS FOR MILD STEEL IN ACIDIC MEDIUM

2021 ◽  
Author(s):  
Petar Stanić ◽  
◽  
Nataša Vukićević ◽  
Vesna Cvetković ◽  
Miroslav Pavlović ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mild Steel ◽  
Acidic Medium ◽  
Corrosion Inhibitors ◽  
Electrochemical Impedance ◽  
Electrochemical Investigation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Hcl Solution ◽  
Scanning Electron

Four 2-thiohydantoin derivatives were synthesized and their corrosion inhibition properties on mild steel (MS) in 0.5M HCl solution was evaluated using usual gravimetric and electrochemical methods (weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS). Morphology of the metal surface was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The study has shown that these compounds provide good protection for mild steel against corrosion in the acidic medium.

Oxydative stress markers and cytokine levels in rosuvastatin-medicated hypercholesterolemia patients

2018 ◽  
Vol 44 (4) ◽  
pp. 530-538
Author(s):  
Aysun Çetin ◽  
İhsan Çetin ◽  
Semih Yılmaz ◽  
Ahmet Şen ◽  
Göktuğ Savaş ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Interleukin 1 ◽  
Paraoxonase 1 ◽  
Enzyme Linked Immunosorbent Assay ◽  
Control Group ◽  
Phenotypic Effect ◽  
Necrosis Factor Alpha ◽  
Stress Markers ◽  
Tnf Α ◽  
Before And After

Abstract Background Limited research is available concerning the relationship between oxidative stress and inflammation parameters, and simultaneously the effects of rosuvastatin on these markers in patients with hypercholesterolemia. We aimed to investigate the connection between cytokines and oxidative stress markers in patients with hypercholesterolemia before and after rosuvastatin treatment. Methods The study consisted of 30 hypercholesterolemic patients diagnosed with routine laboratory tests and 30 healthy participants. The lipid parameters, interleukin-1 beta (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), paraoxonase-1 (PON1) and malondialdehyde (MDA) levels in controls and patients with hypercholesterolemia before and after 12-week treatment with rosuvastatin (10 mg/kg/day), were analyzed by means of enzyme-linked immunosorbent assay. Results It was found that a 12-week cure with rosuvastatin resulted in substantial reductions in IL-1β, IL-6 and TNF-α and MDA levels as in rising activities of PON1 in patients with hypercholesterolemia. Before treatment, the PON1 levels were significantly negatively correlated with TNF-α and IL-6 in control group, while it was positively correlated with TNF-α in patients. Conclusion Our outcomes provide evidence of protected effect of rosuvastatin for inflammation and oxidative damage. It will be of great interest to determine whether the correlation between PON1 and cytokines has any phenotypic effect on PON1.

scholarly journals Small Extracellular Vesicles Isolated from Serum May Serve as Signal-Enhancers for the Monitoring of CNS Tumors

2020 ◽  
Vol 21 (15) ◽  
pp. 5359 ◽  
Author(s):  
Gabriella Dobra ◽  
Matyas Bukva ◽  
Zoltan Szabo ◽  
Bella Bruszel ◽  
Maria Harmati ◽  
...  
Keyword(s):  
Extracellular Vesicles ◽  
Serum Proteins ◽  
Lumbar Disc ◽  
Principal Component ◽  
Cns Tumors ◽  
Serum Samples ◽  
Force Microscopy ◽  
Isolation And Characterization ◽  
Atomic Force ◽  
Patient Groups

Liquid biopsy-based methods to test biomarkers (e.g., serum proteins and extracellular vesicles) may help to monitor brain tumors. In this proteomics-based study, we aimed to identify a characteristic protein fingerprint associated with central nervous system (CNS) tumors. Overall, 96 human serum samples were obtained from four patient groups, namely glioblastoma multiforme (GBM), non-small-cell lung cancer brain metastasis (BM), meningioma (M) and lumbar disc hernia patients (CTRL). After the isolation and characterization of small extracellular vesicles (sEVs) by nanoparticle tracking analysis (NTA) and atomic force microscopy (AFM), liquid chromatography -mass spectrometry (LC-MS) was performed on two different sample types (whole serum and serum sEVs). Statistical analyses (ratio, Cohen’s d, receiver operating characteristic; ROC) were carried out to compare patient groups. To recognize differences between the two sample types, pairwise comparisons (Welch’s test) and ingenuity pathway analysis (IPA) were performed. According to our knowledge, this is the first study that compares the proteome of whole serum and serum-derived sEVs. From the 311 proteins identified, 10 whole serum proteins and 17 sEV proteins showed the highest intergroup differences. Sixty-five proteins were significantly enriched in sEV samples, while 129 proteins were significantly depleted compared to whole serum. Based on principal component analysis (PCA) analyses, sEVs are more suitable to discriminate between the patient groups. Our results support that sEVs have greater potential to monitor CNS tumors, than whole serum.

scholarly journals Effects of Shugan-Jianpi Recipe on the Expression of the p38 MAPK/NF-κB Signaling Pathway in the Hepatocytes of NAFLD Rats

Medicines ◽  
2018 ◽  
Vol 5 (3) ◽  
pp. 106 ◽  
Author(s):  
Yuanjun Deng ◽  
Kairui Tang ◽  
Runsen Chen ◽  
Yajie Liu ◽  
Huan Nie ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
P38 Mapk ◽  
Low Dose ◽  
Serum Levels ◽  
Inflammatory Factors ◽  
Enzyme Linked Immunosorbent Assay ◽  
High Dose ◽  
Model Group ◽  
Necrosis Factor Alpha ◽  
Tnf Α

Background: In traditional Chinese medicine, the Shugan-Jianpi recipe is often used in the treatment of nonalcoholic fatty liver disease (NAFLD). This study aimed to explore the mechanism of the Shugan-Jianpi recipe in relation to rats with NAFLD induced by a high-fat diet. Methods: Rats were randomly divided into eight groups: normal group (NG), model group (MG), low-dose Chaihu–Shugan–San group (L-CG), high-dose Chaihu–Shugan–San group (H-CG), low-dose Shenling–Baizhu–San group (L-SG), high-dose Shenling–Baizhu–San group (H-SG), low dose of integrated-recipes group (L-IG), and high dose of integrated-recipes group (H-IG). After 26 weeks, a lipid profile, aspartate, and alanine aminotransferases in serum were detected. The serum levels of inflammatory factors including interleukin (IL)-1β, IL-6, and tumor necrosis factor-alpha (TNF-α) were analyzed using the enzyme linked immunosorbent assay (ELISA) method. Hepatic pathological changes were observed with hematoxylin-eosin (HE) and oil red O staining. The expression of the p38 mitogen-activated protein kinases (MAPK)/nuclear factor-κB (NF-κB) pathway was detected by quantitative real-time PCR and Western blotting. Results: A pathological section revealed that NAFLD rats have been successfully reproduced. Compared with the model group, each treatment group had different degrees of improvement. The Shugan-Jianpi recipe can inhibit the serum levels of IL-1β, IL-6, and TNF-α in NAFLD rats. The expression of mRNA and a protein related to the p38 MAPK/NF-κB signaling pathway were markedly decreased as a result of the Shugan-Jianpi recipe. Conclusions: The Shugan-Jianpi recipe could attenuate NAFLD progression, and its mechanism may be related to the suppression of the p38 MAPK/NF-κB signaling pathway in hepatocytes.

Angiography significantly decreased serum levels of IL-8 independent of artery stenosis

2020 ◽  
Author(s):  
Lida Zare ◽  
Akram Eidi ◽  
Mohammad Safarian ◽  
Mohammad Kazemi Arababadi
Keyword(s):  
Protective Factor ◽  
Serum Levels ◽  
Artery Stenosis ◽  
Enzyme Linked Immunosorbent Assay ◽  
Dependent Manner ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Before And After ◽  
Elisa Technique ◽  
Factor Alpha

Abstract Background Angiography is a safe cardiovascular technique for the diagnosis and treatment of the cardiovascular disorders. The potential effects of angiography on the cytokines are yet to be clarified completely. Interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-α) are the important pro-inflammatory cytokines that participate in the pathogenesis of artery stenosis. The aim of his project was to study the angiography effects on the serum levels of IL-8 and TNF-α. Methods Fifty-five participants in three groups, without, with one and with more than one artery stenosis, were explored in this project. Serum levels of IL-8 and TNF-α were measured in the participants before and after angiography using enzyme linked immunosorbent assay (ELISA) technique. Results Serum levels of IL-8, but not TNF-α, were significantly decreased following angiography. X-ray doses had moderate positive correlation with serum levels of TNF-α in the patients with more than one artery stenosis. Serum levels of IL-8 and TNF-α were not different among male and female participants in all groups. Discussion Angiography may be a protective factor for inflammation in IL-8 dependent manner. Using angiography in the patients with more than one artery stenosis needs to be executed cautiously.

scholarly journals Electrodeposition of NiSn-rGO Composite Coatings from Deep Eutectic Solvents and Their Physicochemical Characterization

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1455
Author(s):  
Sabrina Patricia Rosoiu ◽  
Aida Ghiulnare Pantazi ◽  
Aurora Petica ◽  
Anca Cojocaru ◽  
Stefania Costovici ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Choline Chloride ◽  
Physicochemical Characterization ◽  
Metallic Matrix ◽  
Deep Eutectic Solvents ◽  
Force Microscopy ◽  
Atomic Force ◽  
Reduced Graphene

The present work describes, for the first time, the electrodeposition of NiSn alloy/reduced graphene oxide composite coatings (NiSn-rGO) obtained under pulse current electrodeposition conditions from deep eutectic solvents (choline chloride: ethylene glycol eutectic mixtures) containing well-dispersed GO nanosheets. The successful incorporation of the carbon-based material into the metallic matrix has been confirmed by Raman spectroscopy and cross-section scanning electron microscopy (SEM). A decrease in the crystallite size of the coating was evidenced when graphene oxide was added to the electrolyte. Additionally, the topography and the electrical properties of the materials were investigated by atomic force microscopy (AFM). The corrosion behavior in 0.5 M NaCl solution was analyzed through potentiodynamic polarization and electrochemical impedance spectroscopy methods for different immersion periods, up to 336 h, showing a slightly better corrosion performance as compared to pure NiSn alloy.

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