Amperometric genosensor for culture independent bacterial count

Area of Science:

• Electrochemistry
• Molecular Biology
• Environmental Science

Background:

• Traditional bacterial plate counts for water quality assessment are time-consuming due to lengthy culturing methods.
• A need exists for rapid, culture-independent methods to determine total bacterial loads.

Purpose of the Study:

• To develop and validate a novel DNA-induced current genosensor for culture-independent total bacteria determination.
• To establish the genosensor's performance in quantifying bacterial DNA as a proxy for bacterial count.

Main Methods:

• The genosensor utilizes electrochemical detection of DNA-induced current generated after bacterial lysis.
• Bacterial DNA reacts with molybdate to form redox molybdophosphate, which is measured electrochemically.
• Spectrometric measurements confirmed the correlation between DNA release and bacterial lysis.

Main Results:

• The genosensor demonstrated a strong correlation between DNA-generated current and bacterial lysis levels for *E. coli* and *S. aureus*.
• *S. aureus* detection limit was 21.9 CFU/mL with a linear range from 3×10^2 to 3×10^7 CFU/mL (R²=0.992).
• *E. coli* analysis showed a detection limit of 25.1 CFU/mL within the same linear range.

Conclusions:

• Electrochemical microbial DNA quantitation offers a novel, culture-independent approach for bacterial counting.
• The genosensor provides rapid (within 1 hour) and sensitive bacterial quantification.
• This technology has potential applications for broad-spectrum bacterial analysis in various fields.