Immobilization techniques to avoid enzyme loss from oxidase-based biosensors: a one-year study

Area of Science:

• Biomedical Engineering
• Biosensor Technology
• Enzyme Immobilization

Background:

• Amperometric sensors for glucose and lactate rely on stable enzyme sensitivity.
• Glutaraldehyde crosslinking is a common method to prevent enzyme loss.
• Limited data exists on glutaraldehyde's effectiveness in enzyme immobilization.

Purpose of the Study:

• To investigate the relationship between enzyme shedding and fabrication procedures in glutaraldehyde crosslinking.
• To determine the impact of glutaraldehyde concentration on sensor performance over one year.

Main Methods:

• Utilized electrochemical testing and spectrophotometric assays.
• Examined enzyme shedding in relation to fabrication.
• Assessed glutaraldehyde concentration effects on sensor performance over a year.

Main Results:

• Enzyme immobilization with glutaraldehyde requires a 24-hour incubation at room temperature.
• A 20-minute rinse in purified water removes excess free glucose oxidase.
• Increased glutaraldehyde concentration can minimize sensitivity decline, despite potentially reducing ultimate sensitivity.

Conclusions:

• Effective glutaraldehyde crosslinking necessitates a rinse step and 24-hour incubation.
• Higher glutaraldehyde concentrations can be used to mitigate sensor sensitivity loss over time.