Electrochemical biosensor with custom fluidics for amplification-free, low-picomolar DNA detection

Area of Science:

• Electrochemistry
• Biosensing
• Molecular Diagnostics

Background:

• Sensitive DNA detection is crucial but challenging in complex biological samples.
• Existing methods like PCR require complex equipment, limiting point-of-care applications.
• Electrochemical biosensors face hurdles like probe variability and sample interference.

Purpose of the Study:

• To develop a robust, label-free, and easy-to-use electrochemical DNA biosensor.
• To enhance hybridization efficiency and minimize matrix interference.
• To enable sensitive and selective DNA detection in complex biological matrices.

Main Methods:

• Integration of screen-printed gold electrodes (AuSPEs) with a 3D-printed fluidic cell.
• Utilizing electrochemical impedance spectroscopy (EIS) for label-free detection.
• Employing COMSOL simulations to optimize convective transport for hybridization.

Main Results:

• Achieved a limit of detection (LOD) of 0.1 pM (0.6 pg/mL) without target amplification.
• Demonstrated successful DNA detection in untreated S. cerevisiae culture supernatants with minimal interference.
• Showcased high selectivity by reliably identifying single-base mismatches and low cross-reactivity.

Conclusions:

• Developed a modular, amplification-free electrochemical biosensing platform for sensitive DNA detection.
• The biosensor is cost-effective, simple to operate, and performs reliably in real-world samples.
• Presents a practical alternative for molecular diagnostics in clinical, environmental, and industrial settings.