Automated detection and quantitation of bacterial RNA by using electrical microarrays

Area of Science:

• Biotechnology
• Electrochemistry
• Molecular Diagnostics

Background:

• Urinary tract infections (UTIs) are commonly caused by specific bacterial pathogens.
• Accurate and rapid identification of these pathogens is crucial for effective treatment.
• Existing diagnostic methods may require lengthy procedures or amplification steps.

Purpose of the Study:

• To develop a novel, sensitive, and automated electrical microarray system for pathogen detection.
• To enable simultaneous identification and quantitation of key UTI-causing bacteria.
• To provide a rapid diagnostic alternative to conventional methods.

Main Methods:

• Utilized low-density electrical 16S rRNA specific oligonucleotide microarrays with nanostructured gold interdigitated array (IDA) electrodes.
• Immobilized thiol-modified oligonucleotides as capture probes for specific 16S rRNA hybridization.
• Employed supporting unlabeled oligonucleotides to enhance RNA hybridization.
• Used biotin-labeled detector oligonucleotides, avidin alkaline phosphatase conjugates, and p-aminophenol for electrochemical signal generation.
• Automated fluidics, multichannel electrical readout, and data handling.

Main Results:

• Achieved sensitive detection and quantitation of Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus, and Staphylococcus epidermidis.
• Demonstrated a limit of detection of 0.5 ng/microL for Escherichia coli total RNA.
• Reported a sensitivity increase of over 60% with the addition of two biotins.
• Validated an automated system for fast and easy procedure without PCR amplification.

Conclusions:

• The developed electrical microarray system offers a sensitive, specific, and automated approach for UTI pathogen diagnostics.
• This technology provides a rapid alternative to traditional culture-based or PCR-based methods.
• The system's automation and high sensitivity make it suitable for clinical settings.