Programming Aptamer-Protein Complexation Kinetics via Modulation of G-Quadruplex Secondary Structure.

Area of Science:

• Biomolecular monitoring
• Aptamer technology
• Biophysical chemistry

Background:

• Aptamers are crucial for biomolecular monitoring but often have slow dissociation rates, causing hysteresis in repeated measurements.
• G-quadruplex structures are common in aptamers, contributing to their specificity but also slow off-kinetics.
• Hysteresis in aptamer binding hinders continuous monitoring applications.

Purpose of the Study:

• To develop a method for modulating G-quadruplex aptamer binding kinetics.
• To accelerate target release from aptamers for improved real-time monitoring.
• To overcome hysteresis limitations in aptamer-based sensing.

Main Methods:

• Utilized a polycytosine strand to interact with G-quadruplex structures.
• Investigated the destabilization of G-quadruplex aptamer structures.
• Measured binding kinetics and target release rates for modified aptamers.
• Tested aptamer performance with targets like thrombin, interferon-gamma, and nucleolin.

Main Results:

• Demonstrated predictable modulation of aptamer binding kinetics.
• Showcased accelerated target release using the polycytosine strand method.
• Confirmed the ability of modified aptamers to capture dynamic analyte concentration changes.
• Achieved measurements on minute time scales, overcoming hysteresis.

Conclusions:

• The polycytosine strand method effectively destabilizes G-quadruplex aptamers, accelerating dissociation.
• This approach enables continuous, real-time biomolecular monitoring by mitigating hysteresis.
• Modified aptamers show promise for dynamic analyte detection in various applications.