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Effects of Experimental Conditions on the Signaling Fidelity of Impedance-Based Nucleic Acid Sensors
Citation:
Vogiazi, V., A. DelaCruz, W. Heineman, R. White, AND D. Dionysiou. Effects of Experimental Conditions on the Signaling Fidelity of Impedance-Based Nucleic Acid Sensors. Analytical Chemistry. American Chemical Society, Washington, DC, 93(2):812-819, (2021). https://doi.org/10.1021/acs.analchem.0c03269
Impact/Purpose:
The presence of high concentrations of cyanotoxins during harmful blooms of cyanobacteria in sources of drinking water supplies seriously threatens human and environmental health. One of the major challenges to assessing the associated health risks is the development of simple, highly selective, and fast-responding sensors to detect these toxins. Thus far, tremendous efforts and resources have been focused on the removal of anthropogenic pollutants from groundwater and drinking water, but relatively little attention has been given to rapid point-of-care monitoring and quantification of cyanotoxins in surface waters experiencing harmful blooms. This proposal aims to address this urgent need by developing highly-selective and fast-responding sensors for cyanotoxins in sources of drinking water where harmful blooms of cyanobacteria frequently occur. Electrochemical biosensors show similar capabilities as immunoassays such as ELISA, a popular screening test for cyanotoxins. Biosensors may be used as a routine quantitative screening and point-of-use water monitoring, mainly because of their high portability. Electrochemical biosensors are developing rapidly and new sensor applications/technologies on multi-cyanotoxin analysis are expected to emerge to properly assist the assessment of toxicity in real time. Real-time/on-line biosensors will certainly allow fast cyanotoxins detection and efficient drinking water quality control, providing people with clean and safe drinking water and prevent recreational exposure.
Description:
Electrochemical impedance spectroscopy (EIS), an extremely sensitive analytical technique, is a widely used signal transduction method for the electrochemical detection of target analytes in a broad range of applications. The use of nucleic acids (aptamers) for sequence-specific or molecular detection in electrochemical biosensor development has been extensive, and the field continues to grow. Although nucleic acid-based sensors using EIS offer exceptional sensitivity, signal fidelity is often linked to the physical and chemical properties of the electrode–solution interface. Little emphasis has been placed on the stability of nucleic acid self-assembled monolayers (SAMs) over repeated voltammetric and impedimetric analyses. We have studied the stability and performance of electrochemical biosensors with mixed SAMs of varying length thiolated nucleic acids and short mercapto alcohols on gold surfaces under repeated electrochemical interrogation. This systematic study demonstrates that signal fidelity is linked to the stability of the SAM layer and nucleic acid structure and the packing density of the nucleic acid on the surface. A decrease in packing density and structural changes of nucleic acids significantly influence the signal change observed with EIS after routine voltammetric analysis. The goal of this article is to improve our understanding of the effect of multiple factors on EIS signal response and to optimize the experimental conditions for development of sensitive and reproducible sensors. Our data demonstrate a need for rigorous control experiments to ensure that the measured change in impedance is unequivocally a result of a specific interaction between the target analyte and nucleic recognition element.
URLs/Downloads:
DOI: Effects of Experimental Conditions on the Signaling Fidelity of Impedance-Based Nucleic Acid Sensors
https://pubmed.ncbi.nlm.nih.gov/33395261/