Fluorogenic target competitors for developing label-free and sensitive folding-unswitching aptamer sensors

Area of Science:

• Biotechnology
• Analytical Chemistry
• Molecular Biology

Background:

• Aptamers are crucial in diagnostics and therapeutics, with structure-switching aptamer sensors (SSAS) widely used for target detection.
• Traditional SSAS require costly modifications and can suffer from reduced sensitivity due to fluorophore/quencher labeling and complex designs.

Purpose of the Study:

• To develop a novel, label-free aptamer sensor platform with enhanced sensitivity.
• To overcome the cost and sensitivity limitations associated with conventional structure-switching aptamer sensors.

Main Methods:

• Developed label-free folding-unswitching aptamer sensors (FUAS) using fluorogenic target competitors.
• Screened natural isoquinoline alkaloids, identifying berberine (BER) as an effective competitor for adenine-based targets.
• Utilized BER's fluorescence, which is modulated by target competition for binding sites on the aptamer.

Main Results:

• The developed FUAS demonstrated significantly higher sensitivity compared to existing SSAS.
• Successfully applied FUAS for detecting ATP and adenosine deaminase in serum samples.
• Validated FUAS for screening inhibitors of adenosine deaminase, proving platform reliability.

Conclusions:

• Fluorogenic target competitors enable the development of label-free FUAS with superior sensitivity.
• This approach offers a cost-effective and high-performance alternative to traditional SSAS.
• The FUAS platform holds promise for diverse applications, including targeted drug delivery.