Equipment-Free Quantitative Aptamer-Based Colorimetric Assay Based on Target-Mediated Viscosity Change

Area of Science:

• Biotechnology
• Analytical Chemistry
• Biosensors

Background:

• Conventional diagnostic assays often require specialized equipment and trained personnel.
• There is a need for simple, cost-effective, and sensitive detection methods, especially for resource-limited settings.
• Aptamer-based assays offer high specificity and affinity for target molecules.

Purpose of the Study:

• To develop a novel aptamer-based colorimetric assay (ABCA) for equipment-free, quantitative detection.
• To integrate enzyme-loaded microparticles for signal amplification and viscosity changes for readout.
• To demonstrate the assay's utility for detecting adenosine in various sample types.

Main Methods:

• Development of an aptamer-based colorimetric assay (ABCA) incorporating enzyme-loaded microparticles.
• Utilizing target-induced selective reduction in reaction solution viscosity for signal generation.
• Employing distance measurement via calibrated glass microsyringes for quantitative readout.
• Validation using adenosine as a model analyte in buffer, human serum, and urine samples.

Main Results:

• The ABCA demonstrated sensitive, selective, and inexpensive detection of adenosine.
• Quantitative results were obtained by simply counting marked bars on calibrated testing containers.
• The assay provided accurate detection in both buffer and real biological samples (serum, urine).
• Naked-eye visualization and equipment-free readout were achieved.

Conclusions:

• The developed ABCA offers a promising platform for sensitive and quantitative analyte detection.
• The assay's simplicity, cost-effectiveness, and equipment-free nature make it suitable for resource-limited settings.
• This method provides a valuable tool for point-of-care diagnostics and field testing.