Highly sensitive detection of influenza virus by boron-doped diamond electrode terminated with sialic acid-mimic peptide
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2016-07-25 |
| Journal | Proceedings of the National Academy of Sciences |
| Authors | Teruhiko Matsubara, Michiko Ujie, Takashi Yamamoto, Miku Akahori, Yasuaki Einaga |
| Institutions | Keio University |
| Citations | 61 |
| Analysis | Full AI Review Included |
PNAS Research Analysis: Boron-Doped Diamond for Highly Sensitive Influenza Detection
Section titled âPNAS Research Analysis: Boron-Doped Diamond for Highly Sensitive Influenza DetectionâExecutive Summary
Section titled âExecutive SummaryâThis analysis details the technical findings of a high-impact research paper demonstrating the ultra-sensitive detection of influenza virus (IFV) utilizing advanced Boron-Doped Diamond (BDD) electrodes manufactured via Microwave Plasma-Assisted Vapor Deposition (MPCVD).
- Core Achievement: Highly sensitive electrochemical detection and quantification of seasonal Influenza Virus (H1N1 and H3N2) using a custom BDD biosensor.
- Material Utilization: A thin, high-quality BDD film was used as the transducer, exploiting its superior electrochemical properties, specifically its wide potential window and minimal adsorption of biomolecules (unlike traditional glassy carbon or platinum).
- Targeted Functionalization: The BDD surface was robustly functionalized with a sialic acid-mimic pentapeptide dimer via an efficient Copper-catalyzed Azide-Alkyne Cycloaddition (Click Chemistry) process.
- Detection Performance: The device demonstrated quantitative detection of IFV in the crucial early phase infection range, achieving limits between 20 and 500 pfu (plaque-forming units) using Electrochemical Impedance Spectroscopy (EIS).
- Selectivity Enhancement: The receptor-mimic peptide was designed to resist neuraminidase (NA) digestion, a common issue with traditional sialyloligosaccharide receptors, thereby maintaining high sensitivity during analysis.
- Application Potential: The methodology establishes a high-performance platform for rapid, early-phase diagnosis of infectious diseases, significantly aiding anti-influenza therapy timelines (effective within 30 hours of symptom onset).
Technical Specifications
Section titled âTechnical SpecificationsâThe following table summarizes the key quantitative and qualitative parameters extracted from the research for replicating or extending the BDD biosensor device.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Analyte Detection Range | 20-500 | pfu | Quantifiable detection of H1N1 and H3N2 IFVs (in 50 ”L volume). |
| Viral Concentration Tested | 400-8,000 | pfu/mL | Range corresponding to the quantifiable 20-400 pfu in 50 ”L. |
| Protein Detection Limit (HA) | 5 | nM | Detection of Hemagglutinin (HA) protein via change in Rct. |
| BDD Substrate Type | Si(111) wafer | - | Polycrystalline BDD deposited via MPCVD. |
| Substrate Diameter | 5 | cm | Standard size used for BDD film deposition. |
| Diamond Quality Verification | 1,332 | cm-1 | Sharp sp3 peak observed via Raman spectroscopy. |
| Surface Coverage (Peptide) | 0.11 | pmol/cmÂČ | Estimated via cyclic voltammogram integration of ferrocenyl tag. |
| Peptide Density | 5.4 | molecules per 100 nmÂČ | Calculated density, confirming sufficient surface sites for IFV capture (IFV size: 80-120 nm). |
| Bare BDD Contact Angle | 68 | ° | Hydrophobic character prior to functionalization. |
| Peptide-Terminated Contact Angle | 47 | ° | Confirms successful conversion to a more hydrophilic surface. |
| Redox Probe | 5 or 10 | mM | Potassium ferro/ferricyanide used in PBS for EIS and CV measurements. |
| IFV Incubation Time | 45 | min | Time required for IFV capture onto the peptide-terminated BDD. |
Key Methodologies
Section titled âKey MethodologiesâThe success of the biosensor relies on precise control over the diamond growth parameters and subsequent multistep chemical modification, optimized for high electrochemical performance.
- BDD Film Synthesis: A thin BDD film was deposited onto a 5-cm Si(111) wafer using a Microwave Plasma-Assisted Vapor Deposition (MPCVD) system.
- Initial Surface Activation (Electroreduction): The BDD surface was electrochemically modified by immobilizing the triisopropylsilyl-protected ethynyl aryl group (TIPS-Eth-Ar) via electroreduction (at approximately -0.01 V).
- Alkyne Group Exposure: The bulky TIPS protecting group was chemically removed (deprotected) to expose the reactive Ethynyl (Alkyne) functional groups, creating the Alkyne-terminated BDD.
- Peptide Synthesis: A specific sialic acid-mimic pentapeptide dimer [(Ala-Arg-Leu-Pro-Arg)2Lys-Lys(N3)] was synthesized, incorporating a terminal Azide (N3) functional group.
- Bioconjugation (Click Chemistry): The Azide-peptide was coupled to the Alkyne-terminated BDD surface via Copper-catalyzed Azide-Alkyne Cycloaddition (CuAAC), incubated for 24 hours, resulting in the Peptide-terminated BDD.
- Binding Assay: The sensor was incubated with IFV solution for 45 minutes, followed by washing.
- Electrochemical Analysis: IFV capture was detected indirectly by measuring the change in charge transfer resistance (Rct) using Electrochemical Impedance Spectroscopy (EIS) with a standard ferro/ferricyanide redox probe.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & Capabilitiesâ6CCVD is positioned as the ideal partner for replicating and scaling the BDD biosensor technology described in this research, leveraging our specialization in high-quality MPCVD diamond materials and custom engineering services.
Applicable Materials
Section titled âApplicable MaterialsâTo achieve the electrochemical selectivity and stability required for this high-sensitivity biosensor, the optimal material is specialized Boron-Doped Polycrystalline Diamond (BDD).
- Material: Heavy Boron-Doped Polycrystalline Diamond (PCD/BDD).
- Specific Recommendations:
- Substrates: BDD films supplied on silicon (Si) substrates, matching the methodology of the paper, or on custom refractory metals for integrated heat management.
- Conductivity Control: Precise control over the boron doping level is critical for ensuring low resistivity while maintaining the broad electrochemical window necessary for sensitive EIS measurements.
- Polishing Grade: Surfaces must be supplied with an ultra-low surface roughness (Ra < 5 nm) to ensure uniform chemical functionalization (alkyne termination) and homogeneous peptide coverage across the active sensing area.
Customization Potential
Section titled âCustomization PotentialâThe research utilized custom dimensions and highly specific surface chemistry. 6CCVD directly supports these requirements:
| Requirement in Paper | 6CCVD Capability Match | Benefit to Research Scale-Up |
|---|---|---|
| 5-cm Wafer Dimensions | Custom Dimensions up to 125 mm. 6CCVD manufactures BDD wafers up to 125 mm (5 inches) in diameter. | Allows immediate scaling from laboratory-scale R&D (5 cm) to pilot manufacturing volumes (125 mm). |
| Surface Activation for Click Chemistry | Custom Chemical Readiness. We provide CVD diamond surfaces with specified terminations (e.g., hydrogen-terminated for electroreduction or oxygen-terminated) ready for tailored alkyne/azide functionalization protocols. | Reduces preparation time and ensures a stable, reactive surface optimized for high-yield bioconjugation. |
| Electrode Integration | Advanced Metalization Services. 6CCVD offers in-house deposition of custom contact metals (Au, Pt, Ti, Cu, W) directly onto the BDD surface or wafer edges. | Enables seamless integration of the BDD chip into analytical or microfluidic systems, providing robust electrical contacts for CV/EIS measurements. |
| Device Shaping | Precision Laser Cutting. We utilize precision laser cutting and etching services to shape the BDD plates/wafers to specific geometries required for custom sensor arrays or chip integration. | Ensures geometric compatibility and minimal material waste when producing final sensor elements. |
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house team of PhD material scientists and engineers specialize in diamond electrochemistry and biosensing platforms. We offer collaborative support for projects targeting:
- Optimization of BDD film thickness (SCD or PCD up to 500 ”m) to manage charge transfer kinetics (Rct).
- Selection of optimal boron doping levels for high signal-to-noise ratio in advanced electrochemical assays like EIS.
- Material consultation for similar viral detection biosensor projects requiring robust surface chemistry and exceptional electrode stability.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Significance A large number of people suffer from influenza every year. Early detection is critical for preventing severe influenza in high-risk groups. There is usually not enough time to produce vaccines against pandemic viruses before they spread to other countries. Anti-influenza therapy using neuraminidase inhibitors is effective within 30 h of the onset of symptoms. Here we show that several dozen plaque-forming units of influenza virus (IFV) are detectable by a boron-doped diamond electrode terminated with a sialic acid-mimic peptide with the ability to capture IFV. The electrode was sufficiently sensitive to detect IFV in specimens obtained in the early phase of infection. The device developed in the present work has potential applications in the highly sensitive detection of IFV to fight against influenza.