Novel Screen-Printed Sensor with Chemically Deposited Boron-Doped Diamond Electrode - Preparation, Characterization, and Application

At a Glance

Metadata	Details
Publication Date	2022-04-13
Journal	Biosensors
Authors	Oleksandr Matvieiev, Renáta Šelešovská, Marián Vojs, Marián Marton, Pavol Michniak
Institutions	University of Pardubice, Palacký University Olomouc
Citations	29
Analysis	Full AI Review Included

Technical Documentation: Screen-Printed Boron-Doped Diamond Electrodes (SP/BDDE)

Executive Summary

This document analyzes the fabrication and performance of novel screen-printed sensors utilizing chemically deposited Boron-Doped Diamond Electrodes (SP/BDDE) via Large-Area Linear Antenna Microwave Chemical Vapor Deposition (LA-MWCVD).

Core Achievement: Successful integration of high-quality, heavily boron-doped diamond films (PCD structure) with low-cost screen-printing technology for disposable sensor applications.
Material Properties: The resulting BDD film exhibited high active boron concentration (2.9 x 10²¹ cm^-3) and low resistivity (1.7 x 10^-2 Ω·cm), confirming metallic conductivity suitable for electroanalysis.
Electrochemical Performance: The sensors demonstrated a wide usable potential window (>3000 mV) and excellent reversibility for outer-sphere redox markers ([Ru(NH₃)₆]^2+/3+), comparable to or exceeding bulk BDDE performance.
Fabrication Method: LA-MWCVD was used to deposit a 3.5 µm thick, sub-microcrystalline BDD film on a ceramic (Al₂O₃) substrate using a high B/C ratio (312,500 ppm in the gas phase).
Analytical Application: Verified for the determination of the anti-inflammatory drug Lornoxicam (LRX) using Differential Pulse Voltammetry (DPV).
Sensitivity and Repeatability: Achieved low Limits of Detection (LOD) down to 9 x 10^-8 mol L^-1 and excellent inter-electrode repeatability (RSD₅ ≤ 1.8% for 2LM-SP/BDDE), validating their use as reliable disposable sensors.

Technical Specifications

Parameter	Value	Unit	Context
BDD Film Thickness	3.5	µm	After 30 h growth on Al₂O₃ substrate
Observed Grain Size	0.2 to 1	µm	Sub-microcrystalline range (PCD structure)
Active Boron Concentration	2.9 x 10²¹	cm^-3	Determined by Hall measurement
Electrical Resistivity	1.7 x 10^-2	Ω·cm	Measured at room temperature
Usable Potential Window	>3000	mV	In 0.1 mol L^-1 H₂SO₄ (BDDE: 3320 mV)
Lornoxicam LOD (Best)	9 x 10^-8	mol L^-1	Using 2LM-SP/BDDE in BRB (pH 3)
Charge Transfer Resistance (R_CT)	2.4	kΩ	Best result for [Fe(CN)₆]^4-/3- (3LM-SP/BDDE)
Charge Transfer Resistance (R_CT)	25	Ω	Best result for [Ru(NH₃)₆]^2+/3+ (3LM-SP/BDDE)
Inter-Electrode Repeatability	≤ 1.8	% (RSD₅)	For Lornoxicam analysis (2LM-SP/BDDE)
Electrode Surface Area (Tested)	0.785, 3.14, 7.07	mm²	Laboratory-made sensors (LM-SP/BDDE)

Key Methodologies

The fabrication of the Novel Screen-Printed Sensor with Chemically Deposited Boron-Doped Diamond Electrode (LM-SP/BDDE) involved a two-step process: BDD deposition via CVD followed by standard screen-printing techniques.

1. BDD Film Deposition (LA-MWCVD)

The heavily boron-doped diamond film was grown using a linear antenna Microwave Chemical Vapor Deposition (LA-MWCVD) reactor (Cube 300, Scia Ltd.).

Substrate: Ceramic (Al₂O₃).
Microwave Power: 6 kW.
Growth Time: 30 h.
Substrate Temperature: 590 °C.
Pressure: 30 Pa.
Precursor Gas Mixture: Trimethyl borate (TMBT), CO₂, and H₂.
TMBT Concentration: 1% (evaporated and introduced).
CO₂ Concentration: 0.2% (with respect to background H₂).
Resulting B/C Ratio (Gas Phase): 312,500 ppm.

2. Screen-Printing and Electrode Formation

The BDD film served as the base material for the working and counter electrodes (WE, CE). Screen-printing was used to define the contacts and the reference electrode (RE).

Silver Layer Printing: Silver particles (AST6025 paste) were printed onto the BDD surface using a polyester mesh (71 threads cm^-1) in a wet-on-wet method (two layers).
Drying/Curing: The silver layer was dried at 150 °C for 30 min.
Reference Electrode (RE) Formation: The printed silver was chlorinated via chronoamperometry (+700 mV for 30 s in 0.1 mol L^-1 KCl) to transform Ag to Ag | AgCl.
Insulation Layer: A silicone-based screen-printing paste (240-SB) was applied using a polyester mesh (32 threads cm^-1) in a wet-on-wet method.
Final Curing: The insulation layer was dried at 150 °C for 120 min.

6CCVD Solutions & Capabilities

The research demonstrates the critical role of high-quality, heavily boron-doped diamond films in creating next-generation, highly stable electrochemical sensors. 6CCVD is uniquely positioned to supply the necessary materials and customization services required to replicate, scale, and extend this research into commercial products.

Applicable Materials

The paper utilized heavily boron-doped diamond with a sub-microcrystalline structure (Polycrystalline Diamond, PCD) and high active boron concentration (2.9 x 10²¹ cm^-3).

Research Requirement	6CCVD Solution	Technical Advantage
Heavily Boron-Doped Diamond	Heavy Boron Doped PCD	Guaranteed metallic conductivity (high B-doping) essential for wide potential window and low R_CT.
Sub-Microcrystalline Structure	PCD Wafers (up to 125mm)	Provides the necessary grain structure for robust screen-printing adhesion and electrochemical activity.
High Purity/Low Noise	Optical Grade SCD/PCD	For applications requiring even lower background currents or integration with optical detection methods.

Customization Potential for Sensor Development

6CCVD’s in-house capabilities directly address the needs of researchers and manufacturers looking to scale up SP/BDDE production or integrate these electrodes into complex systems.

Large-Area Substrates: The paper used small sensor areas (up to 7.07 mm²). 6CCVD supplies PCD plates/wafers up to 125mm in diameter, enabling high-throughput screen-printing and mass production of disposable sensors.
Custom Thickness Control: The paper used a 3.5 µm film. 6CCVD offers precise thickness control for PCD films from 0.1 µm to 500 µm, allowing engineers to optimize material usage and mechanical stability for flexible or rigid substrates.
Advanced Metalization: The integration of the BDDE working electrode requires reliable contacts. 6CCVD offers custom metalization services (Au, Pt, Pd, Ti, W, Cu), ensuring robust, low-resistance ohmic contacts for the WE and CE, and stable interfaces for the Ag/AgCl reference electrode.
Surface Preparation: While the paper used as-grown films for printing, 6CCVD offers precision polishing (Ra < 5nm for PCD). This is crucial for high-resolution electrochemical studies or when integrating the BDDE into microfluidic or flow systems where surface roughness affects flow dynamics and fouling.

Engineering Support

The successful fabrication of the LM-SP/BDDE relies on precise control over the B/C ratio and CVD parameters. 6CCVD’s in-house PhD team specializes in optimizing MPCVD growth recipes to achieve specific electrical and structural properties, such as the high active boron concentration (2.9 x 10²¹ cm^-3) required for this high-performance Lornoxicam sensing application. We provide consultation on:

Doping Optimization: Tailoring the B/C ratio to achieve specific resistivity targets (e.g., matching the 1.7 x 10^-2 Ω·cm achieved in this study).
Substrate Compatibility: Advising on the best diamond material (PCD vs. SCD) and substrate preparation for subsequent screen-printing or microfabrication steps.
Electrochemical Integration: Assisting with material selection for similar projects involving biosensors, environmental monitoring, or point-of-care devices that require wide potential windows and resistance to passivation.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

New screen-printed sensor with a boron-doped diamond working electrode (SP/BDDE) was fabricated using a large-area linear antenna microwave chemical deposition vapor system (LA-MWCVD) with a novel precursor composition. It combines the advantages of disposable printed sensors, such as tailored design, low cost, and easy mass production, with excellent electrochemical properties of BDDE, including a wide available potential window, low background currents, chemical resistance, and resistance to passivation. The newly prepared SP/BDDEs were characterized by scanning electron microscopy (SEM) and Raman spectroscopy. Their electrochemical properties were investigated by cyclic voltammetry and electrochemical impedance spectroscopy using inner sphere ([Fe(CN)6]4−/3−) and outer sphere ([Ru(NH3)6]2+/3+) redox probes. Moreover, the applicability of these new sensors was verified by analysis of the anti-inflammatory drug lornoxicam in model and pharmaceutical samples. Using optimized differential pulse voltammetry in Britton-Robinson buffer of pH 3, detection limits for lornoxicam were 9 × 10−8 mol L−1. The oxidation mechanism of lornoxicam was investigated using bulk electrolysis and online electrochemical cell with mass spectrometry; nine distinct reaction steps and corresponding products and intermediates were identified.

Tech Support

Original Source

DOI: https://doi.org/10.3390/bios12040241

References

2012 - Recent developments and applications of screen-printed electrodes in environmental assays-a review [Crossref]
2014 - Screen-printed electrodes for biosensing: A review (2008-2013) [Crossref]
2016 - Screen-printed electrodes for environmental monitoring of heavy metal ions: A review [Crossref]
2019 - Yttrium hexacyanoferrate microflowers on freestanding three-dimensional graphene substrates for ascorbic acid detection [Crossref]
2020 - Applications of electrochemical sensors and biosensors based on modified screen-printed electrodes: A review [Crossref]
2020 - Screen printed electrodes in biosensors and bioassays. A review [Crossref]