Low-Cost Charged-Coupled Device (CCD) Based Detectors for Shiga Toxins Activity Analysis

Area of Science:

• Food Safety
• Biosensor Technology
• Analytical Chemistry

Background:

• Food-borne pathogens and toxins pose significant risks to public health.
• Existing detection methods can be expensive, complex, or lack portability.
• There is a need for simple, low-cost, and sensitive diagnostic tools for food safety applications.

Purpose of the Study:

• To develop and validate a simple, low-cost, portable detector for food-borne toxins.
• To demonstrate the utility of a webcam-based optical detection system for various assays.
• To assess the performance of the system in detecting active Shiga toxin type 2 (Stx2).

Main Methods:

• A portable, battery-operated CCD-based detection system integrating a webcam, sample plate, LED illumination, and portable computer.
• Utilized a cell-based fluorescence assay measuring the inhibition of green fluorescent protein (GFP) synthesis by Stx2.
• Employed specific excitation (486 nm) and emission (509 nm, detected at 535 nm) filters for GFP fluorescence measurement.

Main Results:

• The developed system successfully detected active Shiga toxin type 2 (Stx2) by measuring reduced GFP fluorescence.
• Achieved a limit of detection (LOD) of 0.1 pg/ml for Stx2, comparable to commercial fluorometers.
• Demonstrated the system's capability for differentiating between biologically active and inactive toxin forms.

Conclusions:

• The low-cost, webcam-based detector is a viable and sensitive tool for detecting food-borne toxins.
• This portable system offers a practical solution for improving food safety monitoring.
• The technology is adaptable for detecting a range of other food-borne toxins and pathogens.