Label-Free Liquid Crystal-Based Dielectric Genosensor for Infectious Bacterial Detection

Area of Science:

• Biomolecular Engineering
• Biosensing Technology
• Molecular Diagnostics

Background:

• Neisseria gonorrhoeae is a significant cause of sexually transmitted infections.
• Current diagnostic methods for N. gonorrhoeae may lack sensitivity or speed.
• Development of rapid and sensitive detection tools is crucial for disease management.

Purpose of the Study:

• To develop and characterize a liquid crystal (LC)-based dielectric genosensor for sensitive detection of Neisseria gonorrhoeae.
• To evaluate the sensing mechanism, sensitivity, specificity, and limit of detection (LOD) of the developed genosensor.
• To compare the performance of the dielectric LC genosensor with optical detection methods.

Main Methods:

• Fabrication of an LC-dielectric sensing platform with immobilized N. gonorrhoeae-specific oligonucleotide probes.
• Utilizing a low-frequency dielectric spectroscopy mechanism (100 Hz) for detecting genomic DNA of N. gonorrhoeae (DNA_N.g).
• Assessing the change in relative permittivity (Δε') upon DNA hybridization and comparing results with optical microscopy.

Main Results:

• The LC-dielectric genosensor showed a linear response in relative permittivity over a wide DNA_N.g concentration range (1 pM to 100 nM).
• Achieved a low LOD of 0.5 pM for DNA_N.g, with a sensitivity of Δε' = 9.38 per decade.
• Demonstrated 20 times higher sensitivity than optical LOD and excellent specificity against related bacterial species.

Conclusions:

• The developed LC-dielectric genosensor provides a highly sensitive and specific method for detecting Neisseria gonorrhoeae DNA.
• Dielectric transduction offers superior performance compared to optical methods for low-level pathogen detection.
• This advanced genosensor holds promise for improved diagnostic capabilities in managing gonorrhea infections.