Turning an aptamer into a light-switch probe with a single bioconjugation

Area of Science:

• Biochemistry
• Analytical Chemistry
• Molecular Biology

Background:

• Structure-switching aptamers offer specific molecular recognition capabilities.
• Lanthanide-based metallointercalators can be used as luminescent probes.
• Controlling the luminescence of intercalators requires specific DNA structures.

Purpose of the Study:

• To develop a single-conjugation method for transforming structure-switching aptamers into luminescent light-switch probes.
• To demonstrate the utility of this method using a mercury ion (Hg2+) aptamer.
• To create a highly selective and sensitive detection system for analytes.

Main Methods:

• A lanthanide-based metallointercalator (Eu-DOTA-Phen) with selective luminescence quenching by purines was employed.
• The metallointercalator was conjugated to a structure-switching aptamer via a single amide bond.
• The probe design involved a partially hybridized aptamer-complementary strand system.

Main Results:

• The luminescent probe exhibits a 21-fold increase in luminescence upon analyte binding.
• The probe demonstrates high selectivity for the target analyte.
• The long luminescence lifetime allows for time-gating to reduce background autofluorescence.

Conclusions:

• The developed method efficiently converts structure-switching aptamers into effective luminescent light-switch probes.
• This approach provides a sensitive, selective, and background-free method for analyte detection.
• The single-conjugation strategy simplifies probe construction and enhances applicability.