A one-step electrochemical strategy for rapid exosome detection using Cu²⁺-coordinated DNA nanoparticles

Area of Science:

• Nanomaterials Science
• Electrochemical Biosensing
• Biomedical Engineering

Background:

• Stimulus-responsive nucleic acid nanomaterials offer label-free electrochemical biosensing capabilities.
• Programmable nanostructures enable target-triggered signal generation in homogeneous systems.
• Exosomes are key biomarkers for diseases like ovarian cancer.

Purpose of the Study:

• To develop a one-step electrochemical strategy for rapid and sensitive detection of ovarian cancer (OC)-derived exosomes.
• To utilize target-responsive Cu²⁺-coordinated DNA nanoparticles (Cu²⁺@DNA-NPs) for label-free signal amplification.
• To establish a biosensor for early OC diagnosis and metastasis monitoring.

Main Methods:

• Incorporation of aptamer sequences into Cu²⁺@DNA-NPs for target recognition.
• Utilizing coordinated Cu²⁺ ions as intrinsic electrochemical reporters.
• Employing hybridization chain reaction (HCR) for signal amplification upon target binding and nanoparticle disassembly.

Main Results:

• Achieved rapid analysis (approx. 35 min) with a low detection limit (9 particles/mL).
• Demonstrated good selectivity against non-target exosomes and interferents, with satisfactory stability and reproducibility.
• Validated the biosensor using clinical samples, successfully discriminating between patients and healthy controls.

Conclusions:

• Established a rational and efficient electrochemical sensing strategy for rapid exosome analysis.
• The developed biosensor shows potential utility in early ovarian cancer diagnosis and metastasis monitoring.
• This label-free, homogeneous sensing approach eliminates the need for electrode modification or additional redox labels.