A high affinity and selective DNA aptamer for copper ions.

Area of Science:

• Biotechnology
• Analytical Chemistry
• Materials Science

Background:

• Development of highly specific and sensitive DNA aptamers is crucial for accurate ion detection.
• Existing copper ion (Cu²⁺) aptamers have limitations in binding affinity and detection sensitivity.
• The SELEX (Systematic Evolution of Ligands by Exponential Enrichment) technique is a powerful tool for aptamer discovery.

Purpose of the Study:

• To select and characterize novel DNA aptamers with high affinity and specificity for Cu²⁺.
• To develop a sensitive sensor for Cu²⁺ detection using the selected aptamers.
• To compare the performance of the new aptamer against previously reported Cu²⁺ aptamers.

Main Methods:

• Capture-SELEX methodology was utilized for the in vitro selection of DNA aptamers targeting Cu²⁺.
• The binding affinity of the selected aptamer (Cu-1) was quantified using a strand-displacement assay.
• A sensor platform was developed to evaluate the limit of detection for Cu²⁺.

Main Results:

• The aptamer designated Cu-1 exhibited a dissociation constant (K_d) of 14.2 nM for Cu²⁺.
• This represents a significant enhancement, approximately 3000-fold, in binding affinity compared to prior Cu²⁺ aptamers.
• The developed sensor demonstrated a low limit of detection (LOD) of 2.1 nM for Cu²⁺.

Conclusions:

• The novel DNA aptamer Cu-1 possesses superior binding affinity and selectivity for Cu²⁺.
• The Cu-1 aptamer-based sensor offers a highly sensitive platform for detecting copper ions.
• This advancement holds promise for improved analytical methods in environmental monitoring and diagnostics.