Lab-on-a-Membrane Foldable Devices for Duplex Drop-Volume Electrochemical Biosensing Using Quantum Dot Tags.

Area of Science:

• Electrochemistry
• Biosensing
• Materials Science

Background:

• Existing biosensing methods often require complex laboratory setups and large sample volumes.
• On-site and rapid detection of multiple analytes remains a challenge for field applications.

Purpose of the Study:

• To develop an integrated, foldable lab-on-a-membrane device for on-site duplex electrochemical biosensing.
• To enable sensitive and simultaneous determination of analytes using minimal sample volumes.

Main Methods:

• Screen-printing fabrication of a nylon membrane device with integrated voltammetric cell and assay zones.
• Utilizing quantum dots (QDs) for labeling in competitive immunoassays.
• Simultaneous anodic stripping voltammetry (ASV) for determination of heavy metals (Pb, Cd) released from QDs.

Main Results:

• Achieved limits of detection of 0.04 μg mL⁻¹ for bovine casein and 0.02 μg mL⁻¹ for bovine immunoglobulin G in milk.
• Demonstrated successful duplex determination in complex milk matrices, including detection of milk adulteration.
• Validated the device's performance for on-site analysis with high sensitivity and simplicity.

Conclusions:

• The developed foldable membrane device offers a cost-effective, portable, and simple solution for on-site duplex electrochemical biosensing.
• This technology presents significant advantages over existing methods for field analysis, including reduced sample volume and enhanced sensitivity.
• The device shows great potential for quality control and detection of adulteration in food and environmental samples.