Graphitic Carbon Nitride: A Reusable and Stable Support for Glucose Oxidase

Area of Science:

• Materials Science
• Biotechnology
• Nanotechnology

Background:

• Enzyme immobilization is crucial for developing reusable biocatalysts and biosensors.
• Graphitic carbon nitride (GCN) is a promising 2D material for biomolecule immobilization due to its unique properties.
• Glucose oxidase (GOx) is a key enzyme for glucose detection and biofuel cells.

Purpose of the Study:

• To immobilize glucose oxidase (GOx) onto 2D thermally exfoliated graphitic carbon nitride (GCN-T) via physical adsorption.
• To characterize the stability, reusability, and activity of the immobilized GOx.
• To evaluate the performance of the GCN-T/GOx bioconjugate as a glucose sensor.

Main Methods:

• Enzyme immobilization using physical adsorption on GCN-T.
• Characterization using STEM-EDS, TGAs, FTIR, and XPS.
• Activity assays, stability tests, and kinetic studies.
• Fabrication and testing of a glucose sensor based on GCN-T/GOx.

Main Results:

• Successful immobilization of GOx onto GCN-T with 88% yield and high activity (0.54 U mg⁻¹).
• The GCN-T/GOx bioconjugate exhibited excellent reusability (81% activity over 10 cycles) and thermal stability.
• Immobilized GOx showed enhanced substrate affinity and no activity loss at 70 °C.
• The glucose sensor demonstrated a linear response, high sensitivity (3.9 μA mM⁻¹ cm⁻²), and low LOD (1 mM).

Conclusions:

• The GCN-T/GOx bioconjugate offers a stable, reusable, and highly active system for enzyme applications.
• This work presents a breakthrough in sustainable enzyme immobilization for advanced biofunctional surfaces.
• The findings provide insights for designing novel biosensors, biocatalysts, and nanomaterials.