A pretreatment-free electrical capacitance biosensor for exosome detection in undiluted serum

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Cancer Diagnostics

Background:

• Exosomes are crucial biomarkers for early cancer diagnosis.
• Current diagnostic methods require time-consuming sample pretreatment.
• There is a need for rapid, sensitive, and specific exosome detection methods.

Purpose of the Study:

• To fabricate a capacitance-based electrical biosensor for direct exosome detection in undiluted serum.
• To utilize a DNA aptamer/molybdenum disulfide (MoS2) heterolayer on an interdigitated micro-gap electrode (IDMGE) system.
• To enhance electrical sensitivity and signal amplification for improved exosome detection.

Main Methods:

• Fabrication of a biosensor system comprising a DNA aptamer/MoS2 heterolayer on an IDMGE/PCB platform.
• Utilizing a thiol-modified CD63 DNA aptamer as a bio-probe for exosome surface protein detection.
• Measuring capacitance changes in response to exosome concentration in undiluted human serum.

Main Results:

• The IDMGE system efficiently amplified the electrical signal for exosome detection.
• The biosensor demonstrated high selectivity and sensitivity, with a detection limit of 2192.6 exosomes/mL.
• A linear relationship was observed between capacitance signal and exosome concentration on a logarithmic scale.

Conclusions:

• The developed capacitance-based electrical biosensor enables label-free detection of exosomes in undiluted serum without pretreatment.
• The integration of DNA aptamers, MoS2 nanoparticles, and IDMGE offers a promising platform for sensitive and specific exosome detection.
• This novel biosensor presents a significant advancement for future early cancer diagnosis strategies.