DNAzyme-Amplified Electrochemical Biosensor Coupled with pH Meter for Ca²⁺ Determination at Variable pH Environments

Area of Science:

• Electrochemistry
• Biosensing
• Animal Health

Background:

• Multiparous cows often experience hypocalcemia due to increased calcium demand during lactation.
• Electrochemical biosensors offer portable calcium ion (Ca2+) detection but are sensitive to pH variations.
• Existing methods struggle with accurate Ca2+ measurement in complex biological samples like blood and milk due to pH fluctuations.

Purpose of the Study:

• To develop a robust electrochemical biosensor for accurate Ca2+ quantification in dairy cows.
• To mitigate the impact of pH variability on Ca2+ detection accuracy.
• To create a practical device for early hypocalcemia detection and management in livestock.

Main Methods:

• Fabrication of an electrochemical biosensor using glassy carbon electrode (GCE) and single-walled carbon nanotube (SWNT) modified with DNAzyme.
• Integration of the biosensor with a pH meter to form a compensated electrochemical device.
• Utilizing Gaussian Process Regression (GPR) for mathematical modeling and accurate data processing.

Main Results:

• The developed electrochemical device accurately determined Ca2+ concentrations from 5 μM to 25 mM within a pH range of 4.0 to 7.5.
• Achieved a low detection limit of 4.2 μM for Ca2+.
• Demonstrated successful application in measuring Ca2+ in real blood and milk samples, overcoming pH interference.

Conclusions:

• The GCE/SWNT/DNAzyme-based electrochemical device effectively measures Ca2+ concentrations, even in the presence of pH variations.
• This technology provides a reliable tool for monitoring and managing calcium levels in dairy cows, potentially preventing hypocalcemia.
• The coupled biosensor-pH meter system offers a significant advancement in portable electrochemical analysis for animal health applications.