Related Experiment Video
Updated: Jun 10, 2026
12:31
A Method for Selecting Structure-switching Aptamers Applied to a Colorimetric Gold Nanoparticle Assay
Published on: February 28, 2015
Tuning Library Length Revealing High Affinity Melamine Aptamers with Opposite Fluorescence Responses for Highly
Stefen Stangherlin1, Sihan Wang1, Celine Fidella1
1Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L3G1, Canada.
Analytical Chemistry
|June 9, 2026
Summary
Aptamers offer a sensitive method for detecting melamine in dairy products. Longer DNA libraries in the selection process yielded superior aptamers for this crucial food safety application.
Area of Science:
- Biotechnology
- Analytical Chemistry
- Food Safety
Background:
- Melamine adulteration in dairy products necessitates reliable detection methods.
- DNA aptamers show promise for melamine sensing due to interactions with DNA bases.
Purpose of the Study:
- To investigate the impact of DNA library length on aptamer selection for melamine detection.
- To develop high-affinity aptamers and a label-free detection strategy for melamine.
Main Methods:
- Capture-SELEX (Systematic Evolution of Ligands by Exponential Enrichment) using DNA libraries of 30 and 36 randomized nucleotides.
- Isothermal titration calorimetry (ITC) to determine aptamer affinity (Kd).
- Thioflavin T fluorescence assay for aptamer screening and limit of detection determination.
Main Results:
- A longer DNA library (36 nucleotides) resulted in greater sequence diversity and a dominant aptamer family.
- High-affinity aptamers with Kd values around 60 nM were identified.
- Aptamers achieved limits of detection as low as 61 nM in buffer and 89 nM in milk samples, with opposite signal readouts.
Conclusions:
- DNA library length significantly influences aptamer selection outcomes.
- Developed aptamers provide a robust, label-free method for sensitive melamine detection in food matrices.
- This research advances aptamer selection strategies and contributes to food safety analysis.
