An aptamer beacon responsive to botulinum toxins

Area of Science:

• Biochemistry
• Molecular Biology
• Analytical Chemistry

Background:

• Botulinum neurotoxin (BoNT) detection is crucial for public health and biosecurity.
• Developing sensitive and specific detection methods for BoNT remains a challenge.

Purpose of the Study:

• To develop and characterize novel DNA aptamers as potential biosensors for BoNT type A.
• To identify aptamer structures with high binding affinity and fluorescence response to BoNT A.

Main Methods:

• Selection of DNA aptamers against BoNT A light chain using SELEX.
• Synthesis and characterization of candidate aptamer beacons with fluorescent labels.
• Evaluation of fluorescence response to varying concentrations of BoNT A and other analytes.

Main Results:

• Sixty candidate aptamers were generated, with Beacon 10 showing the most promising fluorescence response.
• Beacon 10 achieved a limit of detection of 1 ng/mL in buffer and responded to multiple BoNT serotypes in soil suspensions.
• The aptamer showed specificity for BoNTs, with limited cross-reactivity to other peptides, but was ineffective in human serum.

Conclusions:

• Beacon 10 is a sensitive DNA aptamer biosensor for detecting botulinum neurotoxin in environmental samples.
• The study identified potential binding regions within the aptamer structure for BoNT interaction.
• Further optimization may be needed for applications in complex biological matrices like human serum.