Development of an advanced electrochemical DNA biosensor for bacterial pathogen detection

Area of Science:

• Biomedical Engineering
• Molecular Biology
• Analytical Chemistry

Background:

• Electrochemical sensors offer rapid, accurate detection of molecules in biological fluids.
• Bacterial 16S rRNA detection is crucial for identifying pathogens in clinical specimens.
• Previous work established an electrochemical sensor for uropathogen identification.

Purpose of the Study:

• To improve the sensitivity of an electrochemical sensor assay for bacterial 16S rRNA detection.
• To investigate key factors influencing the electrochemical signal amplitude.
• To optimize bacterial lysis and probe design for enhanced detection.

Main Methods:

• Developed an electrochemical sensor assay utilizing hybridization of bacterial 16S rRNA to modified DNA probes.
• Employed fluorescein-modified detector probes and biotin-modified capture probes on a sensor surface.
• Optimized bacterial lysis using Triton X-100, lysozyme, and alkaline treatment.
• Investigated the impact of probe hybridization site distance and fluorescein modification location on signal intensity.

Main Results:

• A combined lysis method (Triton X-100, lysozyme, alkaline) yielded a 12-fold increase in electrochemical signal compared to alkaline lysis alone.
• Optimizing the distance between target hybridization sites and fluorescein modification resulted in a 23-fold change in signal intensity.
• Demonstrated significant improvements in assay sensitivity through optimized lysis and probe design.

Conclusions:

• Optimized bacterial lysis is critical for efficient release of 16S rRNA, enhancing electrochemical signal.
• The spatial arrangement of target-probe and probe-probe interactions significantly impacts signal generation.
• This optimized electrochemical DNA sensor approach shows promise for sensitive bacterial detection in clinical diagnostics.