Smartphone-based kanamycin sensing with ratiometric FRET

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Molecular Biology

Background:

• Smartphone-based fluorescence detection offers potential for on-site biosensing.
• Quantitative field analysis is hindered by excitation and calibration challenges.
• Förster resonance energy transfer (FRET) offers a promising approach for sensitive detection.

Purpose of the Study:

• To develop a rapid and sensitive method for kanamycin detection using smartphone-based fluorescence.
• To utilize ratiometric analysis with FRET between dye pairs on DNA aptamers for quantitative detection.
• To enable on-site, specific, and repeatable kanamycin detection in complex matrices like milk.

Main Methods:

• Developed a FRET-based kanamycin binding aptamer (KBA) sensor utilizing ligand binding-induced aptamer structural changes.
• Employed ratiometric analysis for quantitative fluorescence detection.
• Integrated the KBA sensor with a custom-built smartphone setup for field analysis.

Main Results:

• The KBA sensor demonstrated two linear ranges for kanamycin detection: 0.05–5 nM (LOD 0.18 nM) and 50–900 nM.
• The aptamer exhibited high specificity, even in the presence of milk background.
• The smartphone-based FRET aptamer scheme achieved a linear range of 50–500 nM with an LOD of 28 nM.

Conclusions:

• Ratiometric FRET analysis on DNA aptamers enables rapid, sensitive, and quantitative kanamycin detection.
• The smartphone-based KBA sensor is suitable for on-site, specific, and repeatable analysis.
• This approach overcomes limitations of traditional field fluorescence detection methods.