Development and Comparative Evaluation of Two Enzyme-Based Amperometric Biosensor Designs for Alanine...

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Enzyme Kinetics

Background:

• Alanine aminotransferase (ALT) is a critical liver function biomarker.
• Conventional ALT assays are costly and labor-intensive.
• Biosensors offer a promising, more efficient alternative for ALT detection.

Purpose of the Study:

• To develop and compare two amperometric biosensors for ALT detection using pyruvate oxidase (POx) and glutamate oxidase (GlOx).
• To evaluate the analytical performance and identify the optimal biorecognitive enzymatic configuration for ALT biosensors.

Main Methods:

• Immobilization of POx and GlOx enzymes onto platinum electrodes under optimized conditions.
• Amperometric detection of ALT activity.
• Systematic assessment of analytical parameters including linear range, limit of detection, and sensitivity.

Main Results:

• The POx-based biosensor showed a wider linear range (1-500 U/L) and higher sensitivity (0.75 nA/min at 100 U/L).
• The GlOx-based biosensor had a linear range of 5-500 U/L, comparable limit of detection (1 U/L), but greater stability in complex samples and lower assay costs.
• POx is specific for ALT, while GlOx can be affected by AST but offers versatility for AST detection.

Conclusions:

• A trade-off exists between sensitivity, robustness, and versatility in ALT biosensor design.
• The POx biosensor is ideal for sensitive ALT determination.
• The GlOx biosensor offers a cost-effective and stable alternative, with potential for AST measurement, guiding future clinical device development.