Highly efficient biosensors by using well-ordered ZnO/ZnS core/shell nanotube arrays

Area of Science:

• Materials Science
• Electrochemistry
• Biosensors

Background:

• Developing highly sensitive and selective glucose sensors is crucial for diabetes management.
• Nanostructured metal oxides offer unique electrochemical properties for sensor applications.
• Heterogeneous core/shell nanostructures can enhance sensor performance by combining material properties.

Purpose of the Study:

• To fabricate and characterize efficient glucose sensors using well-ordered ZnO/ZnS core/shell nanotube arrays (CSNAs).
• To evaluate the electrochemical performance of these CSNAs for glucose sensing.
• To investigate the electron transfer properties and stability of the fabricated biosensor.

Main Methods:

• Fabrication of ZnO/ZnS core/shell nanotube arrays (CSNAs) on modified electrodes.
• Electrochemical characterization using ferrocyanide/ferricyanide redox couple.
• Glucose sensing experiments to determine linear range, sensitivity, and limit of detection.
• Evaluation of direct electrochemistry of glucose oxidase and heterogeneous electron transfer rate.

Main Results:

• The ZnO/ZnS CSNAs exhibited superior electrochemical response compared to ZnO nanotube arrays.
• The glucose biosensor showed a linear range from 2.39 × 10⁻⁵ to 2.66 × 10⁻⁴ mM with high sensitivity (188.34 mA mM⁻¹ cm⁻²).
• A low limit of detection (24 μM) and an enhanced heterogeneous electron transfer rate constant (1.69 s⁻¹) were achieved, attributed to high conductivity.

Conclusions:

• ZnO/ZnS CSNAs are highly efficient for glucose sensing, demonstrating improved electrochemical performance.
• The ZnS shell enhances the ZnO surface in biological environments, facilitating future sensor development.
• The high conductivity and fast electron transfer of CSNAs make them promising for advanced biosensor applications.