Immunoglobulin G (IgG), a type of antibody, represents approximately 75% of serum antibodies in humans, and is the most common type of antibody found in blood circulation. Consequently, the development of simple, fast and reliable systems for IgG detection, which can be achieved using electrochemical sandwich-type immunosensors, is of considerable interest. In this study we have developed an immunosensor for human (H)-IgG using an inexpensive and very simple fabrication method based on ZnO nanorods (NRs) obtained through the electrodeposition of ZnO. The ZnO NRs were treated by electrodepositing a layer of reduced graphene oxide (rGO) to ensure an easy immobilization of the antibodies. On Indium Tin Oxide supported on Polyethylene Terephthalate/ZnO NRs/rGO substrate, the sandwich configuration of the immunosensor was built through different incubation steps, which were all optimized. The immunosensor is electrochemically active thanks to the presence of gold nanoparticles tagging the secondary antibody. The immunosensor was used to measure the current density of the hydrogen development reaction which is indirectly linked to the concentration of H-IgG. In this way the calibration curve was constructed obtaining a logarithmic linear range of 10–1000 ng/mL with a detection limit of few ng/mL and good sensitivity.
The issue of monitoring the structural condition of bridges is becoming a top priority worldwide. As is well known, any infrastructure undergoes a progressive deterioration of its structural conditions due to aging by normal service loads and environmental conditions. At the same time, it may suffer serious damages or collapse due to natural phenomena such as earthquakes or strong winds. For this reason, it is essential to rely on efficient and widespread monitoring techniques applied throughout the entire road network. This paper aims to introduce an integrated procedure for structural and material monitoring. With regard to structural monitoring, an innovative approach for monitoring based on Vehicle by Bridge Interaction (VBI) will be proposed. Furthermore, with regard to material monitoring, to evaluate concrete degradation, a non-invasive method based on the continuous monitoring of the pH, as well as chloride and sulfate ions concentration in the concrete, is presented.
Hydrogen peroxide (H2O2) is a biomarker relevant for oxidative stress monitoring. Most chronic airway diseases are characterized by increased oxidative stress. To date, the main methods for the detection of this analyte are expensive and time-consuming laboratory techniques such as fluorometric and colorimetric assays. There is a growing interest in the development of electrochemical sensors for H2O2 detection due to their low cost, ease of use, sensitivity and rapid response. In this work, an electrochemical sensor based on gold nanowire arrays has been developed. Thanks to the catalytic activity of gold against hydrogen peroxide reduction and the high surface area of nanowires, this sensor allows the quantification of this analyte in a fast, efficient and selective way. The sensor was obtained by template electrodeposition and consists of gold nanowires about 5 μm high and with an average diameter of about 200 nm. The high active surface area of this electrode, about 7 times larger than a planar gold electrode, ensured a high sensitivity of the sensor (0.98 μA μM-1cm-2). The sensor allows the quantification of hydrogen peroxide in the range from 10 μM to 10 mM with a limit of detection of 3.2 μM. The sensor has excellent properties in terms of reproducibility, repeatability and selectivity. The sensor was validated by quantifying the hydrogen peroxide released by human airways A549 cells exposed or not to the pro-oxidant compound rotenone. The obtained results were validated by comparing them with those obtained by flow cytometry after staining the cells with the fluorescent superoxide-sensitive Mitosox Red probe giving a very good concordance.
Chronic Obstructive Pulmonary Disease (COPD) is a chronic inflammatory degenerative disease. Disease exacerbations accelerate lung function deterioration. Airway epithelium has a central role in COPD pathophysiology. Airway epithelium releases alarmins including the thymic stromal lymphopoietin (TSLP) in response to exogenous stressors. Notch-1 in the nucleus acts as inhibitor of TSLP gene expression. Here, we investigated, in human bronchial epithelial cells, the effects of cigarette smoke extract (CSE) in TSLP production exploring the relationship with oxidative stress events and with Notch-1 signaling. In CSE exposed 16HBE, the effects of carbocysteine were assessed on: intracellular and extracellular oxidative stress; nuclear Notch-1 expression; TSLP gene expression. The TSLP levels in sera from non-smokers, smokers and exacerbated COPD patients (before and after therapy with carbocysteine) were also explored. CSE induced TSLP gene expression and oxidative stress and reduced nuclear expression of Notch-1 in 16HBE. The use of an electrochemical sensor allowed a reliable tool to assess oxidative stress. TSLP concentrations were higher in sera from smokers and exacerbated COPD than in sera from non-smokers. Carbocysteine was able to counteract the effects of CSE in oxidative stress and in TSLP gene expression in 16HBE and to reduce TSLP in exacerbated COPD. In conclusion, increased oxidative stress induced by smoke exposure in airway epithelium leads to increased TSLP production and carbocysteine in vitro and in vivo mitigates the induced TSLP production. Oxidative stress detection by electrochemical sensors can open new avenues for evaluating epithelial damage and for identifying patients eligible to alarmin targeted biologics.
This paper presents the preliminary results concerning a novel multianalyte sensor platform, developed through laser scribing. Featuring two different working electrodes and one counter and reference electrode, the platform was preliminary used for uric acid detection. Modification of one working electrode with co-electrodeposited reduced graphene oxide and gold nanoparticles enables highly sensitive detection using square-wave voltammetry. This platform holds promising applications for multianalyte rapid and accurate detection in diverse biomedical backgrounds.