HRP/[Zn-Cr-ABTS] redox clay-based biosensor: design and optimization for cyanide detection

Area of Science:

• Electrochemistry
• Biosensors
• Environmental Science

Background:

• Cyanide detection is crucial for environmental monitoring and safety.
• Amperometric biosensors offer sensitive and selective analyte detection.
• Layered double hydroxides provide a versatile platform for enzyme immobilization.

Purpose of the Study:

• To develop a novel, inexpensive, and simple amperometric biosensor for cyanide determination.
• To utilize horseradish peroxidase (HRP) immobilized in a [Zn-Cr-ABTS] layered double hydroxide for electrochemical sensing.
• To investigate the biosensor's performance characteristics, including response time, linear range, sensitivity, and inhibition kinetics for cyanide.

Main Methods:

• Immobilization of HRP within a redox-active [Zn-Cr-ABTS] layered double hydroxide matrix.
• Electrochemical detection based on the reduction of enzymatically formed ABTS radical cation (ABTS+*) at 0.0 V.
• Non-competitive inhibition of HRP activity by cyanide for its quantitative determination.

Main Results:

• The biosensor exhibited a fast response time (8s) to H2O2 with a linear range of 1.7 x 10(-9) to 2.1 x 10(-6) M.
• High sensitivity of 875 mA M(-1) cm(-2) and an apparent Michaelis-Menten constant (KMapp) of 12 µM were achieved.
• Cyanide detection showed a linear response range of 5 x 10(-9) to 4 x 10(-8) M with an apparent inhibition constant (ki) of 1.4 x 10(-7) M.

Conclusions:

• The developed HRP/[Zn-Cr-ABTS] biosensor is effective for sensitive and rapid cyanide detection.
• The inexpensive and simple design makes this biosensor suitable for practical applications in cyanide monitoring.
• The biosensor's performance demonstrates its potential for environmental and industrial safety assessments.