Aptamer-Based Fluorescent Sensor Array for Multiplexed Detection of Cyanotoxins on a Smartphone

Area of Science:

• Environmental Science
• Analytical Chemistry
• Biotechnology

Background:

• Cyanotoxins pose significant risks to environmental and human health.
• Existing detection methods can be slow, complex, or require laboratory settings.
• Need for rapid, portable, and user-friendly monitoring tools for in-field applications.

Purpose of the Study:

• To develop a miniaturized, easy-to-use sensor array for the rapid, multiplexed detection of common cyanotoxins.
• To integrate aptamer-based fluorescent detection with smartphone technology for on-site analysis.
• To create a stable, pre-loaded assay for long-term storage and field deployment.

Main Methods:

• Fabrication of a differential fluorescent sensor array using aptamers and single-stranded DNA (ssDNA) dyes.
• Development of a competitive binding assay for cyanotoxin detection based on fluorescence changes.
• Optimization of aptasensor parameters including dissociation constants and reaction stoichiometry.
• Implementation of an internal intensity correction for accurate quantification.
• Integration with a smartphone for data processing and result display.

Main Results:

• Successful multiplexed detection and discrimination of four cyanotoxins: anatoxin-a (ATX), cylindrospermopsin (CYN), nodularin (NOD), and microcystin-LR (MC-LR).
• Achieved limits of detection (LOD) down to a few nanomolar (<3 nM), meeting drinking water guidelines.
• Demonstrated high chemical specificity against potential interfering agents.
• Validated performance using real lake water samples with various cyanotoxin mixtures.
• Developed a stable assay with a shelf life exceeding 60 days.

Conclusions:

• The developed smartphone-based aptasensor array provides a rapid, sensitive, and specific platform for in-field cyanotoxin monitoring.
• The system's ease of use, portability, and long shelf life make it suitable for environmental surveillance.
• This technology enables timely risk assessment and management of water bodies affected by harmful algal blooms.