An electrochemical amplification immunoassay using biocatalytic metal deposition coupled with anodic stripping voltammetric detection

IEEE Trans. Instrum. Meas.

Borghetti

et al. 2017

Abstract-Measurement systems for early and reliable detection of degenerative diseases, such as Alzheimer's disease (AD), are extremely important in clinical diagnosis. Among these, biochemical assays represent a commonly used method to distinguish patients from healthy population thanks to the sensitive recognition of specific biomarkers in biological fluids. In order to overcome actual limitations of these techniques in term of cost, standardization, and sensitivity, this study aimed to realize a low-cost highly sensitive portable point-of-care (PoC) testing system based on screen-printed electrochemical sensors. The development of the platform specifically included both the design of the sensing probe and the electronic circuit devoted to condition and acquires the transduced electric signal. The designed circuit was implemented in a printed circuit board and interfaced to a wireless system based on bluetooth data transmission in order to improve the portability of the proposed solution. Preliminary results were obtained by using controlled concentrations of electrolytic solutions and calibrating the sensors for antibodies and for a well-known protein (i.e., interleukin 8) quantified by anodic stripping voltammetry (ASV). Findings from ASV measurements showed a sensitivity of 38 µA/(ng/ml) with a tested range from 1.25 to 20 ng/ml, with a limit of detection of 2 ng/ml. Further investigation will include the validation of this PoC device by testing the concentration of a specific p53 protein isoform, which was recently identified to early correlate to AD development.

Section: Discussionsupporting

confidence: 63%

Wireless Point-of-Care Platform With Screen-Printed Sensors for Biomarkers Detection

IEEE Trans. Instrum. Meas.

Borghetti

et al. 2017

“…In detail, each WE was exposed to the following bio-functionalization steps ( Figure 4 ): (i) overnight immobilization of anti-IL-8 antibody to sensor surfaces via drop-casting; (ii) 2-h incubation with recombinant human IL-8, at different concentrations; (iii) 2 h incubation with biotin-labelled detection antibody; (iv) addition of streptavidin-tagged alkaline phosphatase (AP) enzyme that catalyzes the oxidation of ionic Ag (AgNO 3 ) to metallic Ag, thanks to the reaction happening in presence of ascorbic acid (AA-p), as described in [ 34 ]. Once completing the bio-functionalization, sensors were covered with PBS in order to perform the final measurement.…”

Section: Methodsmentioning

confidence: 99%

Aerosol Jet Printed 3D Electrochemical Sensors for Protein Detection

Cantù

et al. 2018

Sensors

The use of electrochemical sensors for the analysis of biological samples is nowadays widespread and highly demanded from diagnostic and pharmaceutical research, but the reliability and repeatability still remain debated issues. In the expanding field of printed electronics, Aerosol Jet Printing (AJP) appears promising to bring an improvement in resolution, miniaturization, and flexibility. In this paper, the use of AJP is proposed to design and fabricate customized electrochemical sensors in term of geometry, materials and 3D liquid sample confinement, reducing variability in the functionalization process. After an analysis of geometrical, electrical and surface features, the optimal layout has been selected. An electrochemical test has been then performed quantifying Interleukin-8, selected as reference protein, by means of Anodic Stripping Voltammetry. AJP sensors have been compared with standard screen-printed electrodes in terms of current density and relative standard deviation. Results from AJP sensors with Ag-based Anodic Stripping Voltammetry confirmed nanostructures capability to reduce the limit of detection (from 2.1 to 0.3 ng/mL). Furthermore, AJP appeared to bring an improvement in term of relative standard deviation from 50 to 10%, if compared to screen-printed sensors. This is promising to improve reliability and repeatability of measurement techniques integrable in several biotechnological applications.

“…For label-based analysis, the biofunctionalization was further completed by the creation of immunocomplexes, including the following steps: i) coating with the specific conformationally altered antibody (PAb 240) for 2 h at RT iii) incubation with alkaline phosphatase (AP)-labeled detection antibody for 1 h 30 min at RT, and iv) incubation in dark conditions for 30 min at RT with the anodic stripping voltammetry (ASV) solution to reduce ionic Ag (AgNO 3 ) to metallic Ag in the presence of ascorbic acid (AA-p) 28 . For every step, 10 µl of each solution was drop-cast on the WE.…”

Section: Methodsmentioning

confidence: 99%

Electrochemical detection of different p53 conformations by using nanostructured surfaces

Stradolini

et al. 2019

Sci Rep

Protein electrochemistry represents a powerful technique for investigating the function and structure of proteins. Currently available biochemical assays provide limited information related to the conformational state of proteins and high costs. This work provides novel insights into the electrochemical investigation of the metalloprotein p53 and its redox products using label-free direct electrochemistry and label-based antibody-specific approaches. First, the redox activities of different p53 redox products were qualitatively investigated on carbon-based electrodes. Then, focusing on the open p53 isoform (denatured p53), a quantitative analysis was performed, comparing the performances of different bulk and nanostructured materials (carbon and platinum). Overall, four different p53 products could be successfully discriminated, from wild type to denatured. Label-free analysis suggested a single electron exchange with electron transfer rate constants on the order of 1 s−1. Label-based analysis showed decreasing affinity of pAb240 towards denatured, oxidized and nitrated p53. Furthermore, platinum nanostructured electrodes showed the highest enhancement of the limit of detection in the quantitative analysis (100 ng/ml). Overall, the obtained results represent a first step towards the implementation of highly requested complex integrated devices for clinical practices, with the aim to go beyond simple protein quantification.