Development of an acetaminophen amperometric biosensor based on peroxidase entrapped in polyacrylamide microgels

• Published in: Biosensors & bioelectronics Vol. 26; no. 5; pp. 1883 - 1889
• Main Authors: González-Sánchez, M.I., Rubio-Retama, J., López-Cabarcos, E., Valero, E.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.01.2011; Elsevier
• Subjects: Acetaminophen; Acetaminophen - analysis; Acetaminophen - chemistry; Acrylic Resins - chemistry; Biological and medical sciences; Biosensing Techniques - instrumentation; Biosensors; Biotechnology; Conductometry - instrumentation; crosslinking; detection limit; Diffusion coefficients; Electrodes; Enzymatic biosensor; Enzymes, Immobilized - chemistry; equations; Equipment Design; Equipment Failure Analysis; Fundamental and applied biological sciences. Psychology; gels; Gels - chemistry; Hill equation; Horseradish peroxidase; Horseradish Peroxidase - chemistry; hydrogen peroxide; Methods. Procedures. Technologies; peroxidase; polyacrylamide; Polyacrylamide microgels; polymerization; Various methods and equipments; Horseradish peroxidase; Acetaminophen; Hill equation; Polyacrylamide microgels; Diffusion coefficients; Enzymatic biosensor; Enzyme; Modeling; Peroxidases; Biosensor; Amperometry; Acrylamide polymer; Microgel; Peroxidase; Oxidoreductases; Diffusion coefficient
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2010.03.024

In this work, horseradish peroxidase (HRP) has been entrapped in cross-linked polyacrylamide microparticles using the concentrated emulsion polymerization method. The feasibility of amperometric detection of acetaminophen (APAP) in a biosensor using this HRP immobilized system as the biological material in the presence of hydrogen peroxide was investigated. We found that the optimum microgel cross-linking degree required to retain the protein and to allow the diffusion of the phenolic drug onto the microparticles was 8%. The apparent diffusion coefficients of APAP across the different microparticles have been calculated using the Cottrell equation. The diffusion coefficients decrease as the microgel cross-linking increases, and the data fit an uniexponential equation well. Those microparticles with a cross-linking degree lower than 5% operated under kinetic control, whereas those whose cross-linking degree was above this value operated under diffusion control. Biosensor response was also optimized to investigate the effect of H 2O 2 concentration and enzyme loading on the current intensity. Under optimal conditions, the sensitivity of this biosensor for APAP was 74.9 mA M −1 cm −2, the detection limit was 3.1 × 10 −6 M based on S/N = 3 and the response time was 135 s. The linear range goes from 1.0 × 10 −5 to 4.9 × 10 −4 M APAP, and can be extended using the Hill equation to 5.7 × 10 −3 M. The biosensor is selective for APAP and was applied to determine the APAP concentration in three commercial pharmaceutical formulations.