Adaptation of a Model Spike Aptamer for Isothermal Amplification-Based Sensing

Area of Science:

• Biotechnology
• Molecular Diagnostics
• Biosensing

Background:

• Isothermal amplification (IA) techniques, including loop-mediated isothermal amplification (LAMP) and rolling circle amplification (RCA), enable rapid DNA/RNA detection at a constant temperature.
• These methods, coupled with colorimetric readouts, are suitable for point-of-need diagnostics in resource-limited settings.
• Current IA utility is confined to nucleic acid targets, limiting broader molecular detection.

Purpose of the Study:

• To broaden the applicability of isothermal amplification techniques to non-nucleic acid targets, such as proteins.
• To develop ligand-responsive IA systems by utilizing aptamers as triggers.
• To demonstrate the use of aptamer conformational changes to regulate LAMP and RCA processes.

Main Methods:

• Employed aptamers targeting SARS-CoV-2 Spike protein as model systems.
• Modified aptamer sequences to serve as templates in LAMP and hyperbranched RCA (HRCA) assays.
• Exploited the dynamic conformational changes of aptamers upon ligand binding to initiate IA.

Main Results:

• Successfully demonstrated that aptamer ligand binding can dynamically regulate both LAMP and HRCA processes.
• Developed a novel aptamer-triggered LAMP assay for protein detection.
• Achieved detection of 50 nM of Spike protein within 30 minutes using a colorimetric readout.

Conclusions:

• Aptamer conformational changes can be effectively utilized to trigger isothermal amplification assays.
• This approach expands the scope of IA technologies to detect a wider range of molecules, including proteins.
• The developed aptamer-LAMP system offers a promising platform for sensitive and rapid point-of-need diagnostics.