Truncated affinity-improved aptamers for 17β-estradiol determination by AuNPs-based colorimetric aptasensor

Area of Science:

• Biotechnology
• Analytical Chemistry
• Environmental Science

Background:

• 17β-estradiol (E2) is an endocrine disruptor that can accumulate in food chains, posing risks to human health.
• Original long-sequence aptamers (E00) require characterization to identify optimal binding domains for accurate E2 detection.

Purpose of the Study:

• To identify the specific binding domain of the 76-mer E00 aptamer responsible for 17β-estradiol (E2) recognition.
• To develop a novel, truncated aptamer with enhanced affinity and specificity for E2 detection.

Main Methods:

• Rational truncation of the 76-mer E00 aptamer by isolating specific structural elements like hairpin and loop regions.
• Comparative analysis of truncated aptamers to determine the minimal sequence with optimal binding characteristics.
• Development of a gold nanoparticle (AuNPs)-based colorimetric assay utilizing the optimized truncated aptamer for E2 quantification.

Main Results:

• A 15-mer truncated aptamer, E09, was developed, exhibiting superior affinity and specificity for E2 compared to the original aptamer.
• The hairpin loop near the 3' end of the original aptamer was identified as a key binding domain for E2.
• The E09 aptamer enabled a sensitive colorimetric determination of E2 with a detection limit of 0.02 μg/mL using AuNPs.

Conclusions:

• The 15-mer truncated aptamer E09 represents a significant advancement for sensitive and specific E2 detection.
• This study provides a proof-of-concept for aptamer truncation strategies, applicable to other long-sequence aptamers.
• The developed method has strong potential for practical applications in monitoring E2 contamination.