Highlights
- Built an Au/ZnO-PVA/CAT/Chitosan electrochemical biosensor for hydrogen peroxide detection.
- Response time under 1 second, detection limit of 9.13 nanomolar, and 93% activity retained after 20 days.
- Validated on real human blood serum samples with 95-106.7% recovery and low interference from common biomolecules.
Abstract
Hydrogen peroxide (H2O2) is toxic at elevated levels and is linked to diseases including Alzheimer's, Parkinson's, cardiovascular disease, and cancer, making fast, low-cost detection in blood serum clinically valuable. This study fabricates an electrochemical biosensor using a zinc oxide-polyvinyl alcohol (ZnO-PVA) nanocomposite interface, with catalase (CAT) enzyme and a chitosan layer immobilized on a gold electrode. The resulting Au/ZnO-PVA/CAT/Chitosan bio-electrode gave a well-defined redox response, a linear detection range of 1-17 micromolar, sensitivity of 210.49 microA/mM per cm^2, a response time under 1 second, a detection limit of 9.13 nanomolar, and 93% retained activity after 20 days of dry storage. The biosensor successfully measured H2O2 spiked into real human blood serum samples, with recoveries of 95-106.7%.
Research summary
Elevated hydrogen peroxide in the body is linked to a range of serious conditions, but existing lab methods for measuring it (Raman spectroscopy, mass spectrometry, chemiluminescence, and others) tend to be complex, slow, and expensive. This study builds a simpler electrochemical alternative: a biosensor combining a zinc oxide-polyvinyl alcohol (ZnO-PVA) nanocomposite interface with an immobilized catalase enzyme, aimed at fast, sensitive hydrogen peroxide detection suitable for blood serum testing.
What the study examined
- Fabrication of an Au/ZnO-PVA/CAT/Chitosan bio-electrode, with catalase (CAT) enzyme immobilized via a chitosan layer on the ZnO-PVA nanocomposite interface
- Electrochemical (cyclic voltammetric) response, linear detection range, sensitivity, response time, and detection/quantification limits
- Long-term dry storage stability over 20 days
- Interference from common biomolecules found in blood: ascorbic acid, lactic acid, urea, and glucose
- Recovery accuracy when tested on real human blood serum spiked with known hydrogen peroxide amounts
Main findings
The Au/ZnO-PVA/CAT/Chitosan bio-electrode gave a well-defined redox response with a linear detection range of 1-17 micromolar, a sensitivity of 210.49 microA per mM per cm^2, a response time under 1 second, a detection limit of 9.13 nanomolar, and a quantification limit of 30.13 nanomolar. The immobilized enzyme retained 93% of its activity after 20 days of dry storage at room temperature, indicating good stability from the ZnO-PVA-enzyme interaction.
Testing against common blood interferents (ascorbic acid, lactic acid, urea, glucose) produced minimal signal change, confirming the sensor’s specificity for hydrogen peroxide. Applied to real human blood serum spiked with known hydrogen peroxide concentrations, the biosensor recovered 95-106.7% of the added amount with a relative standard deviation under 4.56%, indicating good accuracy and repeatability.
Why it matters
By combining a simple nanocomposite interface with an enzyme-based electrochemical readout, the study demonstrates a sensing platform that is fast, highly sensitive, and stable enough to work directly with real blood serum rather than only clean lab buffers — a step toward low-cost, hand-held hydrogen peroxide testing for clinical or point-of-care use.
Citation
N. K. Sekar, M. B. Gumpu, B. L. Ramachandra, N. Nesakumar, Prabakaran Shankar, K. J. Babu, K. Uma Maheswari, J. B. B. Rayappan. Fabrication of Electrochemical Biosensor with ZnO-PVA Nanocomposite Interface for the Detection of Hydrogen Peroxide. Journal of Nanoscience and Nanotechnology 18 (2018) 4371-4379.
