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Published on: June 1, 2012
An electrochemical biosensor with nanointerface for lactate detection based on lactate dehydrogenase immobilized on
Noel Nesakumar1, Kavitha Thandavan, Swaminathan Sethuraman
1Centre for Nanotechnology & Advanced Biomaterials (CeNTAB), SASTRA University, Thanjavur 613 401, Tamil Nadu, India; School of Electrical & Electronics Engineering, SASTRA University, Thanjavur 613 401, Tamil Nadu, India.
Insights
A new electrochemical biosensor using lactate dehydrogenase (LDH) immobilized on zinc oxide (ZnO) nanorods detects elevated blood lactate levels, crucial for diagnosing hepatic immaturity in young children.
Area of Science:
- Biomedical Engineering
- Nanotechnology
- Electrochemistry
Background:
- Hepatic immaturity in children under three is associated with elevated blood lactate concentrations.
- Accurate and rapid lactate detection is vital for diagnosing and managing this condition.
Purpose of the Study:
- To develop a novel electrochemical biosensor for sensitive lactate detection.
- To utilize zinc oxide (ZnO) nanorods for enhanced biosensor performance.
Main Methods:
- Immobilization of lactate dehydrogenase (LDH) onto ZnO nanorods using chitosan at pH 7.4.
- Characterization of ZnO nanorods using XRD and FE-SEM.
- Electrochemical analysis via cyclic voltammetry and amperometry with a three-electrode system.
Main Results:
- The developed biosensor demonstrated high sensitivity (1.832 μA μmol(-1) L) and a wide linear range (0.2-0.8 μmol L(-1)).
- Achieved low detection and quantification limits (4.73 nmol L(-1) and 15.75 nmol L(-1) respectively) with a rapid response time (<1 s).
- Michaelis-Menten parameters (KM(app) = 0.38 μmol L(-1), Imax = 2.798 μA) and good repeatability/reproducibility were reported.
Conclusions:
- The Au/NanoZnO/LDH biosensor offers a promising tool for accurate and rapid lactate monitoring.
- This technology can aid in the early diagnosis of hepatic immaturity in pediatric patients.
Abstract:
Hepatic immaturity is observed particularly in children whose age is under three, when the lactate concentration is greater than the normal level in blood. An electrochemical lactate biosensor was developed by immobilizing lactate dehydrogenase (LDH) on to ZnO nanorods at pH 7.4 via chitosan. Growth of polycrystalline ZnO nanorods towards (101) plane was confirmed using XRD. The FE-SEM study revealed the formation of ZnO nanorods with an aspect ratio of 3.24. Immobilization of LDH on ZnO nanorods was confirmed using FTIR spectra and surface coverage. Electrochemical studies were carried out through cyclic voltammetry and amperometry using three electrode system with Au/NanoZnO/LDH as working electrode, Ag/AgCl in 0.1 M KCl as reference electrode and Pt wire as counter electrode. The sensitivity of the biosensor was found to be 1.832 μA μmol(-1) L exhibiting linearity 0.2-0.8 μmol L(-1) with the detection and quantification limits of 4.73 and 15.75 nmol L(-1) respectively. The response time of Au/NanoZnO/LDH bioelectrode was found to be <1 s. Prediction band for net current was framed to enhance specificity. Michaelis-Menten constant (KM(app)) and maximum rate (Imax) values for immobilized LDH were found to be 0.38 μmol L(-1) and 2.798 μA respectively. Repeatability and reproducibility of LDH biosensor were also reported.
