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Surface Modification of Screen-Printed Carbon Electrode through Oxygen Plasma to Enhance Biosensor Sensitivity
Shuto Osaki1, Masato Saito1,2, Hidenori Nagai1
1AIST-Osaka University Advanced Photonics and Biosensing Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, Photonics Center, Osaka University, 2-1 Yamadaoka, Suita 565-0871, Osaka, Japan.
Oxygen plasma treatment enhances screen-printed carbon electrodes (SPCEs) for biosensors by creating carboxyl groups. This improves antibody immobilization, significantly boosting sensitivity and lowering the limit of detection for point-of-care testing (POCT) applications.
Area of Science:
- Electrochemistry
- Materials Science
- Biosensor Technology
Background:
- Screen-printed carbon electrodes (SPCEs) are cost-effective and widely used in point-of-care testing (POCT) biosensors.
- Modifying the chemically stable carbon surface for enhanced biosensing performance presents a significant challenge.
- Oxygen plasma (O2) treatment offers a potential method to functionalize carbon surfaces for improved biomolecule immobilization.
Purpose of the Study:
- To investigate the electrochemical impact of O2-plasma treatment on SPCEs for biosensor applications.
- To compare the efficacy of covalent antibody bonding versus physical adsorption on plasma-treated and bare electrodes.
- To optimize immunosensor performance by understanding plasma-induced surface modifications.
Main Methods:
- Comparison of four SPCE modification strategies: O2-plasma-treated/covalent antibody, O2-plasma-treated/physical antibody, bare/covalent antibody, and bare/physical antibody.
- Utilizing a novel immunosensor based on gold nanoparticles (AuNPs).
- Electrochemical characterization and performance evaluation including limit of detection (LOD) and linear response range sensitivity.
Main Results:
- O2-plasma treatment generated carboxyl groups on the SPCE surface, altering electrochemical properties via electrostatic interactions.
- The O2-plasma-treated electrode with covalent antibody bonding (a) exhibited the lowest LOD (0.50 ng/mL) and highest sensitivity (slope 0.039).
- Case (a) showed a 2.4-fold improvement in LOD compared to the conventional physical adsorption on a bare electrode (d), demonstrating significantly enhanced antibody modification.
Conclusions:
- O2-plasma treatment is an effective method for modifying SPCE surface conditions, increasing carboxyl group density.
- This surface modification significantly improves the efficiency of antibody immobilization and overall immunosensor performance.
- O2-plasma treatment presents a simple and promising approach for functionalizing printed carbon electrodes with various molecular recognition elements for advanced biosensing.
