Titanium dioxide-mediated resistive nanobiosensor for E. coli O157:H7.

Area of Science:

• Nanotechnology
• Biosensing
• Molecular Diagnostics

Background:

• Conventional methods for detecting Escherichia coli O157:H7 (E. coli O157:H7) DNA are time-consuming, often exceeding three days.
• There is a need for rapid, sensitive, and reproducible methods for E. coli O157:H7 detection, particularly in food safety applications.

Purpose of the Study:

• To develop and characterize a titanium dioxide nanoparticle (TiO2 NP)-mediated resistive biosensor for the rapid determination of E. coli O157:H7 DNA fragments.
• To evaluate the performance of the biosensor in terms of sensitivity, analytical range, detection limit, and reproducibility.

Main Methods:

• Synthesis of TiO2 NPs using the sol-gel method.
• Fabrication of interdigitated sensor electrodes via microlithography.
• Detection of E. coli O157:H7 DNA using a current-voltage (I-V) measurement without DNA amplification, based on charge interactions.

Main Results:

• The TiO2 NP biosensor achieved a sensitivity of 1.67 × 10^13 Ω/M with a wide analytical range.
• The limit of detection was as low as 1 × 10^-11 M for DNA.
• The sensor demonstrated excellent repeatability and reproducibility, detecting DNA within 15 minutes in a 1 μL sample.

Conclusions:

• The developed TiO2 NP resistive biosensor provides a rapid and highly sensitive platform for E. coli O157:H7 DNA detection.
• This electronic biosensor overcomes the lengthy preparation and detection times associated with conventional methods.
• The biosensor shows significant potential for real-time monitoring and early detection of E. coli O157:H7 in various samples.