Pilot study of electrochemical reduction of selected nucleotides and double-stranded DNA at pristine micro-/ultrananocrystalline boron-doped diamond electrodes at very negative potentials
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2024-12-20 |
| Journal | Electrochimica Acta |
| Authors | Michal AugustĂn, Vlastimil VyskoÄil, Ondrej SzabĂł, KateĆina AubrechtovĂĄ DragounovĂĄ, Rene Pfeifer |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThis pilot study successfully demonstrated the electrochemical reduction of various purine and pyrimidine nucleotides (AMP, ADP, ATP, dGMP, CMP, TMP) and double-stranded DNA (dsDNA) using pristine microcrystalline (B-MCDE) and ultrananocrystalline (B-UNCDE) Boron-Doped Diamond Electrodes (BDDEs) at highly negative potentials.
- Novel Reduction Signals: Electrochemical reduction of AMP and CMP nucleotides was observed in the far region of the Hydrogen Evolution Reaction (HER), a phenomenon previously unreported for carbonaceous electrodes.
- Surface Termination Effects: O-terminated BDDEs (hydrophilic) generally facilitated the reduction of all tested analytes (except dsDNA), while H-terminated B-MCDE (hydrophobic) failed to reduce Guanosine 5â-monophosphate (GMP).
- Protocol Optimization: A proposed protocol involving 30 s incubation and N2 purging significantly enhanced the repeatability of results (typically <5% relative standard deviation) and improved signal magnitude, especially on H-B-MCDE surfaces.
- HER Interference: Voltammetric determination of analytes in the HER region required very high concentrations (e.g., AMP determination was limited to 2Ă10-3 M and greater at O-B-MCDE) to suppress hydrogen generation effects.
- Antifouling Properties: The BDDEs exhibited excellent antifouling characteristics, allowing for repeatable determination of high analyte concentrations with minimal passivation.
- Future Direction: The study validates BDDEs as promising, non-toxic alternatives to mercury electrodes for DNA electrochemistry, particularly when utilizing hydrophilic O-terminated surfaces.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| B-MCDE Film Thickness | 2.5 | ”m | Deposited on Si (111) substrate |
| B-UNCDE Film Thickness | 3 | ”m | Deposited on Si (111) substrate |
| B-MCDE Grain Size | 0.5-1 | ”m | Micrometre-sized faceted granular structures |
| B-UNCDE Grain Size | 20-70 | nm | Ultrananocrystalline nature |
| B-MCDE Specific Resistivity | 7.6 | mΩ cm | Measured via four-point probe |
| B-UNCDE Specific Resistivity | 3.7 | mΩ cm | Measured via four-point probe |
| B-MCDE Boron Doping Level | 9.2Ă1020 | cm-3 | Estimated from Raman B1a peak (478 cm-1) |
| B-UNCDE Boron Doping Level | 2.4Ă1021 | cm-3 | Estimated from Raman B1a peak (458 cm-1) |
| Electrode Active Area Diameter | 4.0 | mm | Circular shape (12.6 mm2) |
| Optimal LSV Scan Rate | 1000 | mV/s | Linear Sweep Voltammetry (LSV) experiments |
| LSV Potential Step | 2.4 | mV | Used in voltammetric experiments |
| Analyte Stock Concentration | 1Ă10-2 | M | GMP, dGMP, AMP, ADP, ATP, CMP, TMP |
| AMP Determination Range (O-B-MCDE) | 2Ă10-2 to 2Ă10-3 | M | Voltammetric determination in presence of HER |
| Electrolyte pH | 7.4 | - | 0.1 mol/L Phosphate Buffer (PB) |
Key Methodologies
Section titled âKey MethodologiesâThe BDDE films were fabricated using a Linear Antenna Microwave Chemical Vapour Deposition (LA MWCVD) reactor on Si (111) substrates, followed by specific electrochemical activation protocols.
1. BDD Film Deposition (LA MWCVD)
Section titled â1. BDD Film Deposition (LA MWCVD)â| Parameter | B-MCD | B-UNCD | Unit | Notes |
|---|---|---|---|---|
| Substrate Temperature (Ts) | 600 | 600 | °C | Constant for all experiments |
| Microwave Power (PMW) | 6 | 6 | kW | - |
| Gas Mixture Pressure (p) | 30 | 30 | Pa | - |
| Deposition Duration (t) | 30 | 30 | h | - |
| H2 Flow | 500 | 500 | sccm | - |
| TMBT Flow (Carbon/Boron Source) | 5 | 10 | sccm | Trimethyl borate |
| CO2 Flow | 1 | 1 | sccm | CO2 to H2 concentration 0.2% |
| CH4 Flow (Crystal Size Reduction) | - | 5 | sccm | Methane added for UNCD growth |
2. Electrode Surface Pretreatment and Activation
Section titled â2. Electrode Surface Pretreatment and ActivationâThe pristine BDDEs were subjected to specific electrochemical procedures to achieve O- or H-termination, followed by a standardized voltammetric protocol.
| Termination Type | Deposition Potential (Edep) | Deposition Time (tdep) | Resulting Surface |
|---|---|---|---|
| O-terminated (Anodic) | +3.0 V | 1 min | O-B-MCDE / O-B-UNCDE (Hydrophilic) |
| H-terminated (Cathodic) | -3.0 V | 1 min | H-B-MCDE (Hydrophobic) |
3. Voltammetric Analysis Protocol
Section titled â3. Voltammetric Analysis Protocolâ- Deaeration: Analyte solution (15 mL) purged with N2 for 20 minutes.
- Surface Renewal: Electrochemical activation (O- or H-termination) performed immediately before measurement.
- Incubation (Preadsorption): Working electrode rinsed (5 s) and placed in the analyte solution for 30 s (tinc=30 s).
- Measurement: Linear Sweep Voltammetry (LSV) scan performed (1000 mV/s).
Commercial Applications
Section titled âCommercial ApplicationsâThe technology developed in this study, utilizing highly conductive and chemically inert boron-doped diamond electrodes, is relevant to several high-value engineering and commercial sectors:
- Electroanalysis and Biosensing:
- DNA/Nucleotide Detection: BDDEs provide a stable platform for monitoring DNA damage, drug-DNA interactions, and nucleotide concentrations, offering a non-toxic alternative to traditional mercury electrodes.
- High-Sensitivity Sensors: The wide potential window and low background currents characteristic of BDDEs enable the detection of analytes (like AMP and CMP) at extreme negative potentials.
- Wastewater Treatment (WWT):
- BDDEs are widely used as anodes for the destruction of persistent organic pollutants via the anodic generation of hydroxyl radicals. The high boron content and low sp2 carbon content (achieved in these films) enhance conductivity and suppress competing reactions (HER/OER), improving WWT efficiency.
- Electrochemical Device Manufacturing:
- Robust Electrodes: The mechanical and chemical stability of BDDEs makes them ideal for harsh environments or applications requiring frequent, aggressive electrochemical cleaning/renewal.
- Material Science and Thin Film Technology:
- Advanced CVD Processes: The precise control over micro- and ultrananocrystalline film growth (using LA MWCVD and TMBT/CH4 gas mixtures) provides a pathway for manufacturing highly customized diamond materials for specific electrochemical needs.
Tech Support
Section titled âTech SupportâOriginal Source
Section titled âOriginal SourceâReferences
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