Electrochemical Impedance Immunoassay for ALS-Associated Neurofilament Protein: Matrix Effect on the Immunoplatform

Abstract

Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disorder, which has complex diagnostic steps. Electrochemical immunoassays may make the diagnosis simpler and faster. Here, we present the detection of ALS-associated neurofilament light chain (Nf-L) protein through an electrochemical impedance immunoassay on reduced graphene oxide (rGO) screen-printed electrodes. The immunoassay was developed in two different media, i.e., buffer and human serum, to compare the effect of the media on their figures of merit and calibration models. The label-free charge transfer resistance (RCT) of the immunoplatform was used as a signal response to develop the calibration models. We found that exposure of the biorecognition layer to human serum improved the impedance response of the biorecognition element with significantly lower relative error. Moreover, the calibration model obtained in the human serum environment has higher sensitivity and a better limit of detection (0.087 ng/mL) than the buffer medium (0.39 ng/mL). The analyses of the ALS patient samples show that concentrations obtained from the buffer-based regression model was higher than the serum-based model. However, a high Pearson correlation (r = 1.00) between the media suggests that concentration in one medium may be useful to predict the concentration in the other medium. Moreover, the Nf-L concentration appears to increase with age in both male and female groups, while overall higher Nf-L was found in the male group than the female group.

Novel Multiparametric Bioelectronic Measurement System for Monitoring Virus-Induced Alterations in Functional Neuronal Networks

“…The statistical analysis of these biological parameters revealed a virus-amount- and time-dependent increase in C Para , as well as a decrease in R Ser ( Figure S6C,D ). This proves the suitability of impedance spectroscopy as a monitoring technique for degeneration of cell layers and cytotoxic effects and correlates with previous studies of impedance spectroscopy-based neurodegeneration monitoring on neuronal cell lines [ 13 , 15 , 22 ]. In this context, the decrease of up to 92% means the extreme degeneration and damage of the whole cell layer, at least for the higher virus concentration.…”

Comparison of Different Electrochemical Methodologies for Electrode Reactions: A Case Study of Paracetamol

“…A deep insight into electrochemical reactions on the surface of electrodes is essential to understanding the processes in catalysis, electrolysis, batteries, sensors, and fuel cells [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Cyclic voltammetry-a simple, easy, and common technique-is a front-line tool to investigate reactions on electrode surfaces.…”

Electrochemical Biosensor for Point-of-Care Testing of Low-Abundance Biomarkers of Neurological Diseases

“…Because it has the advantages of providing simultaneous, rapid, and quantitative detection and analysis of a variety of unknown substances, it is a good electrode material. Electrochemical biosensors, because of their advantages of low cost, simplicity, rapidity, and high sensitivity, hold great promise for highly sensitive detection of biomarkers associated with neurological diseases. − …”