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Electrochemical sensor based on Arthrobacter globiformis for cholinesterase activity determination
Margarita Stoytcheva1, Roumen Zlatev, Benjamin Valdez
1University of Mining and Geology, Department of Chemistry, Studentski grad, 1700 Sofia, Bulgaria. stoytcheva@hotmail.com
Biosensors & Bioelectronics
|December 27, 2005
Summary
This study introduces a novel bacterial sensor for cholinesterase activity, utilizing whole Arthrobacter globiformis cells on an oxygen probe. This biosensor offers enhanced stability and longevity compared to traditional amperometric enzymatic sensors.
Area of Science:
- Biotechnology
- Biosensor Development
- Enzyme Activity Measurement
Background:
- Amperometric enzymatic sensors for cholinesterase activity suffer from short lifetimes, instability, and electrode passivation.
- Existing sensors often require enzyme immobilization, leading to reduced stability and increased costs.
Purpose of the Study:
- To develop a novel, stable, and cost-effective biosensor for cholinesterase activity determination.
- To overcome the limitations of conventional amperometric enzymatic sensors.
Main Methods:
- Whole cells of Arthrobacter globiformis, containing choline oxidase, were immobilized on a Clark-type oxygen probe.
- Sensor response was measured as current proportional to bacterial respiration.
- The sensor utilized dissolved oxygen as a mediator for choline detection.
Main Results:
- The bacterial sensor demonstrated high response stability and extended operational lifetime (>7 weeks at ambient temperature).
- A linear response to choline was observed up to 2 x 10(-4) M, with a detection limit of 8 x 10(-8) M.
- A linear calibration for cholinesterase activity was achieved up to 11 mU/cm³, with high accuracy (2.82% relative error) in serum samples.
Conclusions:
- The proposed bacterial biosensor offers a robust and reliable alternative for cholinesterase activity measurement.
- Immobilizing whole cells preserves enzyme activity and enhances sensor performance, stability, and longevity.
- This approach provides a cost-effective and interference-free method for biosensing applications.