This paper investigates the electrochemical behavior of p-aminophenol (PAP) on commercially available carbon screen-printed electrodes (CSPEs) and gold screen-printed electrodes (GSPEs) at neutral and basic pHs for the development of inexpensive immunoassays. The electrochemical oxidative signal from PAP results from its adsorption to the electrode. The formation of self-assembled monolayers on gold electrodes prevented PAP adsorption but also reduced its oxidative current, confirming that adsorption increases signal production. On bare electrodes, PAP adsorption results in oxidative current variability depending on the electroactive surface area of the screen-printed electrode. This variability could not be remedied by cleaning and reusing the same GSPE. Decreasing the PAP concentration to 3.8 μM greatly improved the consistency of the measurements, suggesting that the adsorption of PAP is concentration-dependent. Multiple PAP oxidations on the same electrode caused polymerization, limiting PAP in continuous monitoring applications. Infrared and Raman spectroscopy allow the distinction between adsorbed PAP and electropolymerized PAP on the surface of a gold wafer. The results from this study suggest that the use of PAP production in immunoassays with SPEs must be fine-tuned, and electrodes must be cleaned or disposed of between measurements.
Preterm birth (PTB) is the top cause of death in newborns and the second leading cause of death in children under the age of five. Certain cytokines, like interleukin-6 (IL-6), and matrix metalloproteinases (MMPs) are known to facilitate the degradation of the fetal membrane, but the mechanisms that result in fetal membrane rupture under both normal and pathological conditions are largely unknown. Our fetal membrane-on-a-chip model will allow us to investigate the conditions and mechanisms that precede fetal membrane rupture. Our enzymatic electrochemical detection platform allows us to detect biosignatures from the fetal membrane by measuring analyte concentration changes such as glucose utilization, lactate production, and oxygen consumption. Addition of electrochemical sensors for cytokine and MMPs to the detection platform will provide further insight into the mechanisms underlying PTB by offering low-level protein biomarker quantification. We are currently fabricating and optimizing electrochemical immunoassays for the detection of IL-6 and MMP-3 to leverage the advantages of electrochemical techniques in studying preterm births. The current protein assay design utilizes the enzyme alkaline phosphatase attached to the target protein. When introducing the substrate p-aminophenyl phosphate (PAPP) to the system, it is enzymatically converted to p-aminophenol (PAP). Upon oxidation, PAP is converted to p-quinone (PQI). We are currently studying the electrochemical behavior of PAP/PQI for application in immunoassays. We are investigating the use of different electrochemical techniques for PAP oxidation to PQI including cyclic voltammetry, square wave voltammetry, differential pulse voltammetry, and normal pulse voltammetry to see how the technique affects the reproducibility of assay measurements.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.