There is a great demand to broaden our understanding of the multifactorial complex etiology of
neurodegenerative diseases to aid the development of more efficient therapeutics and slow down the
progression of neuronal cell death. The role of co-transmission and the effect of environmental factors
on such diseases have yet to be explored adequately, mainly due to the lack of a proper analytical tool
that can perform simultaneous multi-analyte detection in real time with excellent analytical parameters.
In this study, we report a simple fabrication protocol of a double-bore carbon-fiber microelectrode
(CFM) capable of performing rapid simultaneous detection of neurotransmitters and Cu2+ via fast-scan
cyclic voltammetry (FSCV) in Tris buffer. After imaging our CFMs via optical microscopy and scanning
electron microscopy to ensure the intact nature of the two electrodes in our electrode composite, we
performed a detailed analysis of the performance characteristics of our double-bore CFM in five
different analyte mixtures, Cu2+-5HT, Cu2+-DA, Cu2+-AA, 5-HT-DA, and 5-HT-AA in Tris buffer, by
applying different analyte-specific FSCV waveforms simultaneously. Calibration curves for each analyte in
each mixture were plotted while extracting the analytical parameters such as the limit of detection
(LOD), linear range, and sensitivity. We also carried out a control experiment series for the same mixtures
with single-bore CFMs by applying one waveform at a time to compare the capabilities of our doublebore CFMs. Interestingly, except for the Cu2+-DA solution, all other combinations showed improved
LOD, linear ranges, and sensitivity when detecting simultaneously with double-bore CFMs compared to
single-bore CFMs, an excellent finding for developing this sensor for future in vivo applications.
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This content will become publicly available on March 1, 2025
Gold Nanoparticle-Modified Carbon-Fiber Microelectrodes for the Electrochemical Detection of Cd2+ via Fast-Scan Cyclic Voltammetry
Neurotoxic heavy metals, such as Cd2+, pose a significant global health concern due to their increased environmental contamination and subsequent detrimental health hazards they pose to human beings. These metal ions can breach the blood-brain barrierblood–brain barrier, leading to severe and often irreversible damage to the central nervous system and other vital organs. Therefore, developing a highly sensitive, robust, and rapid in vivo detection method for these hazardous heavy metal ions is of the utmost importance for early detection, thus initiating timely therapeutics. Detecting ultra-low levels of toxic metal ions in vivo and obtaining accurate speciation information remains a challenge with conventional analytical techniques. In this study, we fabricated a novel carbon carbon-fiber microelectrode (CFM)-based sensor that can detect Cd2+ ions using fast-scan cyclic voltammetry by electrodepositing gold nanoparticles (AuNP). We optimized electrochemical parameters that generate a unique cyclic voltammogram (CV) of Cd2+ at a temporal resolution of 100 ms with our novel sensor. All our experiments were performed in tris buffer that mimics the artificial cerebellum fluid. We established a calibration curve resulting in a limit of detection (LOD) of 0.01 µM with a corresponding sensitivity of 418.02 nA/ µM. The sensor’s selectivity was evaluated in the presence of other metal ions, and it was noteworthy to observe that the sensor retained its ability to produce the distinctive Cd2+ CV, even when the concentration of other metal ions was 200 times higher than that of Cd2+. We also found that our sensor could detect free Cd2+ ions in the presence of complexing agents. Furthermore, we analyzed the solution chemistry of each of those Cd2+–ligand solutions using a geochemical model, PHREEQC. The concentrations of free Cd2+ ions determined through our electrochemical data align well with geochemical modeling data, thus validating the response of our novel sensor. Furthermore, we reassessed our sensor’s LOD in tris buffer based on the concentration of free Cd2+ ions determined through PHREEQC analysis, revealing an LOD of 0.00132 µM. We also demonstrated the capability of our sensor to detect Cd2+ ions in artificial urine samples, showcasing its potential for application in actual biological samples. To the best of our knowledge, this is the first AuNP-modified, CFM-based Cd2+ sensor capable of detecting ultra-low concentrations of free Cd2+ ions in different complex matrices, including artificial urine at a temporal resolution of 100 ms, making it an excellent analytical tool for future real-time, in vivo detection, particularly in the brain.
more » « less- Award ID(s):
- 2301577
- NSF-PAR ID:
- 10496841
- Publisher / Repository:
- MDPI
- Date Published:
- Journal Name:
- Micromachines
- Volume:
- 15
- Issue:
- 3
- ISSN:
- 2072-666X
- Page Range / eLocation ID:
- 294
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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