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6CCVD Research

Boron-doped diamond nanosheet volume-enriched screen-printed carbon electrodes - a platform for electroanalytical and impedimetric biosensor applications

At a Glance

Section titled “At a Glance”
MetadataDetails
Publication Date2023-09-22
JournalMicrochimica Acta
AuthorsMateusz Ficek, Mateusz Cieƛlik, Monika Janik, Mateusz Brodowski, MirosƂaw Sawczak
InstitutionsUniversity of GdaƄsk, Warsaw University of Technology
Citations8
AnalysisFull AI Review Included

Executive Summary

Section titled “Executive Summary”

This research details the development and validation of a novel, high-performance electrochemical platform: Boron-Doped Diamond Nanosheet full-volume-enriched Screen-Printed Carbon Electrodes (BDDPE).

  • Core Innovation: BDD nanosheets (4% wt) are fully integrated into the volume of a screen-printed carbon paste (DuPont BQ221), providing enhanced charge transfer and scalability.
  • Electrochemical Performance: The BDDPE demonstrated a greatly improved Electrochemically Active Surface Area (EASA), showing up to 67% enhancement compared to standard Screen-Printed Electrodes (PE) using the outer sphere electron transfer probe [Ru(NH3)6]2+/3+.
  • Biosensor Application: The platform was functionalized via diazonium salt electrografting and zero-length cross-linker chemistry to create a selective impedimetric biosensor for Haemophilus influenzae (Hi).
  • Ultra-Low Detection Limit: The sensor achieved an ultra-low Limit of Detection (LOD) of 1 CFU/mL for Hi bacteria using Electrochemical Impedance Spectroscopy (EIS).
  • Speed and Specificity: Detection was achieved rapidly (under 10 minutes, including 5 minutes incubation). The system exhibited high specificity towards Hi protein D, with a tolerance limit for interference from other pathogens set at 12%.
  • Stability and Cost: The BDDPE showed robust potential stability over 12 hours and was designed as a disposable sensor, costing approximately 15 Euro cents per test.

Technical Specifications

Section titled “Technical Specifications”
ParameterValueUnitContext
Electrode TypeBDDPEN/ABoron-doped diamond nanosheet SPE
BDD Nanosheet Loading4% wtFiller in DuPont BQ221 carbon paste
BDDPE Geometric Area (WE)0.152cm2Working Electrode surface area
BDDPE Thickness110”mEstimated structure thickness
EASA Enhancement (OSET probe)67%Compared to PE using [Ru(NH3)6]2+/3+
EASA Enhancement (ISET probe)10%Compared to PE using K3[Fe(CN)6]
Hi Limit of Detection (LOD)1CFU/mLMeasured via EIS
Protein D Linear Range10-7 to 10-2”g/mLCalibration curve linearity
Detection Time< 10minTotal time, including 5 min incubation
Interference Tolerance Limit12%Maximum non-specific signal observed
OCP Stability (BDDPE-RE)< 10mVPotential deviation over 12 hours
Final Curing Temperature180°CCuring time: 15 min (in vacuum)
EIS Frequency Range10 kHz to 1Hz10 points per decade

Key Methodologies

Section titled “Key Methodologies”
  1. BDD Nanosheet Synthesis: Boron-doped diamond foils were produced in a one-step growth process using Microwave Plasma-Assisted Chemical Vapour Deposition (MWPACVD) on a tantalum substrate.
  2. Foil Preparation: The synthesized BDD foils were mechanically processed (shredding and grinding for 15 min) using a ceramic grinder to yield fragments (~2 ”m flakes).
  3. Paste Formulation: The BDD foil fragments were mixed into DuPont BQ221 carbon paste at a concentration of 4% wt using a mechanical stirrer (30 min).
  4. Screen Printing: The BDDPE paste was screen-printed onto the substrate using a semi-automatic screen printer equipped with a 325 mesh steel screen.
  5. Thermal Curing: The printed electrodes underwent final curing at 180 °C for 15 minutes in a vacuum environment.
  6. Surface Functionalization (Two-Step Process):
    • Step 1 (Electrografting): Electroreduction of diazonium salt (4-aminobenzoic acid) was performed at the BDDPE surface to create amine-terminated sites.
    • Step 2 (Antibody Anchoring): Anti-protein D monoclonal mouse antibodies were immobilized onto the surface using zero-length cross-linkers (EDC/NHS chemistry).
  7. Electrochemical Detection: Impedimetric measurements (EIS) were conducted at the redox potential EF (-0.13 V vs BDDPE pseudo-reference electrode) using 1 mM K3[Fe(CN)6] dissolved in PBS, following a 5-minute sample incubation.

Commercial Applications

Section titled “Commercial Applications”

The BDDPE technology provides a scalable, high-performance platform for electrochemical devices, leveraging the unique properties of boron-doped diamond in a cost-effective screen-printed format.

  • Point-of-Care (POC) Diagnostics: Rapid, disposable biosensors for the ultra-sensitive detection of bacterial pathogens (e.g., Haemophilus influenzae), viruses, and biomarkers, suitable for resource-limited settings.
  • High-Performance Electroanalysis: Utilization of the enhanced EASA and wide electrolytic window for advanced electrocatalytic applications, including the detection of heavy metals, neurotransmitters, and complex organic molecules.
  • Scalable Sensor Manufacturing: The use of screen-printing methodology allows for high-volume, low-cost production of diamond-based electrodes, overcoming the material cost and size limitations of traditional BDD wafers.
  • Low Biofouling Medical Devices: The inherent antifouling properties of the BDD surface make these electrodes ideal for continuous monitoring or sensing in complex biological fluids (e.g., blood, serum) where non-specific binding is a major challenge.
  • Pseudo-Reference Electrodes: The demonstrated potential stability of the BDDPE material allows it to function reliably as a pseudo-reference electrode, simplifying the design of integrated, all-carbon three-electrode systems.
View Original Abstract

Abstract This paper focuses on the development of a novel electrode based on boron-doped diamond nanosheet full-volume-enriched screen-printed carbon electrodes (BDDPE) for use as an impedimetric biosensor. Impedimetric biosensors offer high sensitivity and selectivity for virus detection, but their use as point-of-care devices is limited by the complexity of nanomaterials’ architecture and the receptor immobilisation procedures. The study presents a two-step modification process involving the electroreduction of diazonium salt at the BDDPE and the immobilisation of antibodies using zero-length cross-linkers for a selective impedimetric biosensor of Haemophilus influenzae (Hi). The incorporation of diamond nanosheets into BDDPE leads to enhanced charge transfer and electrochemical behaviour, demonstrating greatly improved electrochemically active surface area compared with unmodified screen-printed electrodes (by 44% and 10% on average for [Ru(NH 3 ) 6 ]Cl 2 and K 3 [Fe(CN) 6 ], respectively). The presented sensing system shows high specificity towards protein D in Hi bacteria, as confirmed by negative controls against potential interference from other pathogens, with an estimated tolerance limit for interference under 12%. The Hi limit of detection by electrochemical impedance spectroscopy was 1 CFU/mL (measured at − 0.13 V vs BDDPE pseudo-reference), which was achieved in under 10 min, including 5 min sample incubation in the presence of the analyte. Graphical abstract

Tech Support

Section titled “Tech Support”

Original Source

Section titled “Original Source”

References

Section titled “References”
  1. 2004 - Semiconductors and semimetals

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