On-chip sample preparation and analyte quantification using a microfluidic aqueous two-phase extraction coupled with...

Area of Science:

• Analytical Chemistry
• Biotechnology
• Environmental Science

Background:

• Immunoassays offer rapid and sensitive analyte quantification but are hindered by matrix interference in real-world samples.
• Current methods for immunoassays often require extensive sample preparation, limiting their application in point-of-care settings.
• Developing integrated systems for direct sample analysis is crucial for advancing portable diagnostic tools.

Purpose of the Study:

• To develop an integrated microfluidic device for simultaneous matrix clean-up, analyte pre-concentration, and immunoassay detection.
• To demonstrate the device's efficacy in quantifying the mycotoxin ochratoxin A (OTA) in a wine matrix.
• To assess the potential of this integrated system for simplifying point-of-care testing in complex samples.

Main Methods:

• An integrated microfluidic device comprising two modules: aqueous two-phase extraction (ATPE) for clean-up/pre-concentration and an immunoassay for quantification.
• Model analyte: ochratoxin A (OTA) in a wine matrix.
• Validation of the device's performance, including limit of detection (LoD) and linear response range.

Main Results:

• Achieved a limit of detection (LoD) of 0.26 ng mL(-1) for OTA in red wine, significantly below the EU regulatory limit of 2 ng mL(-1).
• Demonstrated a wide linear response range spanning three orders of magnitude (0.1-100 ng mL(-1)) on a logarithmic scale.
• Obtained comparable results for different wine matrices (red and white) and performance close to assays in buffer alone (LoD = 0.15 ng mL(-1)).

Conclusions:

• The integrated microfluidic device effectively performs simultaneous matrix clean-up, analyte pre-concentration, and immunoassay detection.
• This novel approach using aqueous two-phase systems enables direct analysis of real samples in complex matrices, eliminating the need for external extraction processes.
• The developed system holds significant promise for advancing point-of-care devices for food safety and other applications.