Dual range lactate oxidase-based screen printed amperometric biosensor for analysis of lactate in diversified samples

Area of Science:

• Electrochemistry
• Biosensor Technology
• Biomedical Engineering

Background:

• Lactate concentration is a key biomarker in sports performance, healthcare diagnostics, and industrial applications (food, cosmetics).
• Accurate and versatile lactate determination methods are crucial for various analytical needs.
• Existing methods may have limitations in terms of cost, sample compatibility, or measurement range.

Purpose of the Study:

• To develop a screen-printed biosensor for lactate determination over a broad concentration range.
• To utilize lactate oxidase (LOx) immobilized with copper metallic framework (Cu-MOF) for enhanced performance.
• To validate the biosensor's efficacy in real-world samples like sweat, saliva, and wine.

Main Methods:

• Development of a screen-printed biosensor incorporating lactate oxidase (LOx) crosslinked with Cu-MOF in a chitosan matrix.
• Electrochemical detection of enzymatic products on a platinum-modified electrode at a potential of 0.15 V (vs SPE Ag/AgCl).
• Characterization of the biosensor's response across different lactate concentrations, including catalysis and inhibition zones.

Main Results:

• The biosensor exhibited linear responses in two distinct ranges: 0.75 µM to 1 mM (catalysis) and up to 50 mM (substrate inhibition).
• Achieved a low limit of detection of 0.75 µM and excellent reproducibility below 7%.
• Successfully applied the biosensor for non-invasive lactate measurement in human sweat and saliva, and in wine samples.

Conclusions:

• The developed LOx-based biosensor offers a versatile and sensitive platform for quantifying lactate in diverse samples.
• Its ability to measure across wide concentration ranges makes it suitable for both low and high lactate levels.
• The low-cost, non-invasive nature and successful application in real samples highlight its practical utility.