An Electrochemical Sensor of Theophylline on a Boron-Doped Diamond Electrode Modified with Nickel Nanoparticles

At a Glance

Metadata	Details
Publication Date	2023-10-20
Journal	Sensors
Authors	Prastika Krisma Jiwanti, Anis Puspita Sari, Siti Wafiroh, Yeni Wahyuni Hartati, Jarnuzi Gunlazuardi
Institutions	University of Indonesia, Padjadjaran University
Citations	17
Analysis	Full AI Review Included

Technical Documentation & Analysis: BDD/NiNP Electrochemical Sensor

Executive Summary

This technical analysis focuses on the development of a highly sensitive electrochemical sensor for Theophylline, utilizing a Boron-Doped Diamond (BDD) electrode modified with Nickel Nanoparticles (NiNPs). The results validate the superior electrocatalytic performance of modified diamond materials, directly aligning with 6CCVD’s core offerings in high-performance BDD substrates.

Core Achievement: Successful fabrication of a BDD/NiNP electrochemical sensor for theophylline detection via a simple electrodeposition method (chronoamperometry).
Performance Enhancement: The NiNP modification resulted in an 8-fold increase in the electrochemically active surface area, rising from 0.0011 cm² (unmodified BDD) to 0.0081 cm².
Detection Limit: The modified electrode achieved a low Limit of Detection (LOD) of 2.79 µM, significantly improving upon the unmodified BDD LOD of 4.58 µM.
Selectivity and Stability: The sensor demonstrated excellent selectivity against common biological interferents (D-glucose, urea, ammonium sulfate) and high reproducibility (RSD 1.36%).
Real-World Validation: The method was successfully applied to artificial urine samples, achieving high recovery (105.10%), confirming its promise for clinical and pharmaceutical monitoring applications.
6CCVD Relevance: This research underscores the critical role of high-quality, customizable Boron-Doped Diamond substrates, a specialty material provided by 6CCVD, for advanced electrochemical sensing.

Technical Specifications

The following hard data points were extracted from the research paper detailing the performance and characteristics of the BDD/NiNP electrode:

Parameter	Value	Unit	Context
Electrochemically Active Surface Area (BDD/NiNP)	0.0081	cm²	8x increase over unmodified BDD
Electrochemically Active Surface Area (BDD)	0.0011	cm²	Unmodified baseline
Limit of Detection (LOD)	2.79	µM	BDD/NiNP electrode performance
Linear Concentration Range	30 to 100	µM	Theophylline sensing range
Optimum pH	3.0	-	Phosphate Buffer Solution (PBS)
NiNP Average Particle Size	82.27	nm	Determined via SEM/ImageJ analysis
NiNP Electrodeposition Potential	-1.2	V	Applied during chronoamperometry
Deposition Time	250	s	Duration of NiNP electrodeposition
Real Sample Recovery	105.10	%	Artificial urine analysis (BDD/NiNP)
Reproducibility (%RSD)	1.36	%	BDD/NiNP electrode (n=8)
Theophylline Oxidation Potential (BDD/NiNP)	+1.30	V	vs. Ag/AgCl reference electrode

Key Methodologies

The experimental procedure focused on optimizing the BDD surface and controlling the NiNP deposition parameters to maximize electrocatalytic activity.

BDD Pretreatment: The BDD electrode was sonicated sequentially in 1-propanol and ultrapure water for 5 minutes each to clean the surface.
Electrode Optimization: The BDD surface was electrochemically optimized in 0.1 M H₂SO₄ using Cyclic Voltammetry (CV) with a scan rate of 1 V/s over 40 scans, spanning a potential range of -2.0 V to +2.0 V.
NiNP Precursor Solution: A 1 mM NiSO₄ solution was prepared in 0.1 M acetic buffer solution at pH 5.5.
NiNP Electrodeposition: Nickel nanoparticles were deposited onto the BDD surface using chronoamperometry at a constant potential of -1.2 V for 250 seconds.
Characterization: The modified BDD/NiNP electrode was analyzed using Scanning Electron Microscopy (SEM) for morphology and X-ray Photoelectron Spectroscopy (XPS) to confirm the presence of metallic Ni (Ni⁰) and Ni(OH)₂ (Ni²⁺ species).
Electrochemical Sensing: Square Wave Voltammetry (SWV) and Cyclic Voltammetry (CV) were performed in 0.1 M PBS (pH 3.0) to determine theophylline concentration and study the irreversible oxidation mechanism (involving two protons and two electrons).

6CCVD Solutions & Capabilities

6CCVD is uniquely positioned to supply the foundational BDD materials and customization services required to replicate, scale, and advance this high-performance electrochemical sensing technology.

Applicable Materials

To achieve the high stability and low background current demonstrated in this research, high-quality Boron-Doped Diamond (BDD) is essential.

Heavy Boron-Doped Polycrystalline Diamond (PCD): Ideal for large-area electrochemical sensors and industrial scale-up. 6CCVD provides PCD wafers up to 125mm in diameter, ensuring high conductivity and mechanical robustness required for modification processes like electrodeposition.
Boron-Doped Single Crystal Diamond (SCD): For applications demanding the highest purity, lowest defect density, and ultimate surface smoothness (Ra < 1nm), 6CCVD offers BDD SCD, which would ensure highly uniform NiNP deposition and superior reproducibility.

Customization Potential

The success of this sensor relies on precise material geometry and surface preparation. 6CCVD offers comprehensive customization services that directly support the needs of electrochemical sensor development:

Research Requirement	6CCVD Customization Service	Technical Advantage
Electrode Dimensions	Custom plates and wafers up to 125mm (PCD). Precision laser cutting and shaping services.	Supply BDD electrodes cut precisely to fit proprietary electrochemical cells or sensor arrays, minimizing material waste and integration complexity.
Thickness Control	SCD/PCD thickness ranging from 0.1µm to 500µm. Substrates available up to 10mm thick.	Allows engineers to optimize electrode resistance and thermal management for high-frequency or high-current applications.
Surface Preparation	Polishing services achieving Ra < 1nm (SCD) and Ra < 5nm (inch-size PCD).	Ultra-smooth surfaces are critical for ensuring uniform nanoparticle nucleation and deposition, leading to the low %RSD (1.36%) observed in the study.
Metalization for Contact	In-house metalization capabilities including Au, Pt, Pd, Ti, W, and Cu.	While the paper used Ni electrodeposition, 6CCVD can supply BDD substrates pre-patterned with robust contact pads (e.g., Ti/Au) or adhesion layers, streamlining the researcher’s subsequent modification steps.

Engineering Support

6CCVD’s in-house team of PhD material scientists specializes in MPCVD diamond growth and surface functionalization. We offer expert consultation to assist researchers and engineers in replicating or extending this work:

Material Selection: Guidance on selecting the optimal BDD grade (PCD vs. SCD) and doping level for specific electrochemical applications, such as trace detection of Theophylline or other narrow therapeutic range drugs.
Surface Preparation Protocols: Assistance in developing pre-treatment and cleaning protocols necessary to ensure maximum adhesion and uniformity of subsequent nanoparticle modifications (like NiNPs).
Global Logistics: Reliable global shipping (DDU default, DDP available) ensures rapid delivery of custom diamond materials, accelerating research timelines worldwide.

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

View Original Abstract

Theophylline is a drug with a narrow therapeutic range. Electrochemical sensors are a potentially effective method for detecting theophylline concentration to prevent toxicity. In this work, a simple modification of a boron-doped diamond electrode using nickel nanoparticles was successfully performed for a theophylline electrochemical sensor. The modified electrode was characterized using a scanning electron microscope and X-ray photoelectron spectroscopy. Square wave voltammetry and cyclic voltammetry methods were used to study the electrochemical behavior of theophylline. The modified nickel nanoparticles on the boron-doped diamond electrode exhibited an electrochemically active surface area of 0.0081 cm2, which is larger than the unmodified boron-doped diamond’s area of 0.0011 cm2. This modified electrode demonstrated a low limit of detection of 2.79 µM within the linear concentration range from 30 to 100 µM. Moreover, the modified boron-doped diamond electrode also showed selective properties against D-glucose, ammonium sulfate, and urea. In the real sample analysis using artificial urine, the boron-doped diamond electrode with nickel nanoparticle modifications achieved a %recovery of 105.10%, with a good precision of less than 5%. The results of this work indicate that the developed method using nickel nanoparticles on a boron-doped diamond electrode is promising for the determination of theophylline.

Tech Support

Original Source

DOI: https://doi.org/10.3390/s23208597

References

2013 - Theophylline [Crossref]
2020 - Systemic medications in chronic obstructive pulmonary disease: Use and outcomes [Crossref]
2016 - Design, synthesis, anticancer, antimicrobial actiities and molecular docking studies of theophylline containing acetylenes and theo-phylline containing 1,2,3-triazoles with variant nucleoside derivatives [Crossref]
2017 - Pre-diction of serum theophylline concentrations and cytochrome P450 1A2 activity by analyzing urinary metabolites in preterm infants [Crossref]
2010 - Rapid determination of methylxanthines in real samples by high-performance liquid chromatography using the new FastGradient® narrow-bore monolithic column [Crossref]
2019 - Carbon nanoparticle-protected RNA aptasensor for amplified fluorescent determination of theophylline in serum based on nuclease-aided signal amplification [Crossref]
2019 - Derivative UV-spectroscopic determination of theophyl-line, salbutamol sulfate and glycerylguaicolate in syrup mixture [Crossref]
2018 - Highly sensitive gold nanoparticle-based electrochemical aptasensor for the-ophylline detection [Crossref]
2018 - Highly sensitive determination of the-ophylline based on graphene quantum dots modified electrode [Crossref]