Microcystin-LR label-free immunosensor based on exfoliated graphite nanoplatelets and silver nanoparticles

Area of Science:

• Electrochemistry
• Environmental Science
• Nanotechnology

Background:

• Microcystin-LR (MC-LR) is a potent toxin found in water bodies, posing risks to aquatic ecosystems and human health.
• Accurate and rapid detection methods for MC-LR are crucial for environmental monitoring and public safety.
• Existing detection methods can be time-consuming or require complex sample preparation.

Purpose of the Study:

• To develop a simple, rapid, and label-free immunosensor for the accurate determination of MC-LR in water samples.
• To utilize a novel hybrid nanocomposite material for enhanced sensor performance.
• To evaluate the sensor's sensitivity, precision, selectivity, and applicability in real water samples.

Main Methods:

• Immobilization of anti-MC-LR antibodies onto a hybrid nanocomposite (AgNP-Nafion-xGnP) via adsorption.
• Fabrication of a glassy carbon electrode (GCE)-based immunosensor in a single step.
• Optimization of square-wave voltammetry (SWV) parameters and incubation time.
• Analysis of MC-LR concentration using electrochemical oxidation current.

Main Results:

• The immunosensor exhibited a linear response for MC-LR in the range of 0.5-5000 ng/mL.
• A low detection limit of 0.017 ng/mL was achieved.
• High precision was demonstrated with inter-day (4.5%) and intra-day (3.1%) coefficients of variation.
• The sensor showed good selectivity and was successfully applied to real water samples.

Conclusions:

• The developed label-free immunosensor offers a simple, rapid, and accurate method for MC-LR detection.
• The AgNP-Nafion-xGnP hybrid nanocomposite enhances sensor performance.
• This platform presents advantages over existing electrochemical sensors, particularly in reduced incubation time, making it suitable for routine analytical applications.