Structure-switching fluorescence aptasensor for sensitive detection of chloramphenicol

Area of Science:

• Biochemistry
• Analytical Chemistry
• Molecular Biology

Background:

• Chloramphenicol is a broad-spectrum antibiotic with significant regulatory limits due to toxicity.
• Sensitive and accurate detection methods for chloramphenicol are crucial for food safety and environmental monitoring.
• Existing detection methods often face challenges with sensitivity, specificity, or complex procedures.

Purpose of the Study:

• To investigate the performance of a chloramphenicol aptamer, including its binding thermodynamics, structure switching, and binding domain.
• To develop a novel fluorescence aptasensor for sensitive chloramphenicol detection.
• To achieve signal amplification using exonuclease I and hybridization chain reaction.

Main Methods:

• Isothermal titration calorimetry, circular dichroism, and molecular docking were used to characterize the aptamer.
• A fluorescence aptasensor was designed incorporating exonuclease I (Exo I) and hybridization chain reaction (HCR).
• The mechanism involves chloramphenicol-induced aptamer structure switching, DNA dissociation, Exo I cleavage, and HCR signal amplification.

Main Results:

• The aptamer's binding thermodynamics, structure switching, and binding domain were elucidated.
• The developed aptasensor demonstrated a wide linear range (0.001–100 nM) for chloramphenicol detection.
• A low detection limit of 0.3 pM was achieved, with successful application in real samples like milk and lake water.

Conclusions:

• The study presents a novel and highly sensitive fluorescence aptasensor for chloramphenicol detection.
• The combination of aptamer structure switching, Exo I, and HCR provides effective signal amplification.
• This approach offers a promising strategy for developing sensitive aptasensors for various target compounds.