Towards portable rapid TB biosensor: Detecting Mycobacterium tuberculosis in raw sputum samples using functionalized...

Area of Science:

• Biosensor technology
• Molecular diagnostics
• Electrochemistry

Background:

• Tuberculosis (TB) remains a major global health challenge, causing 1.5 million deaths annually, predominantly in low- to middle-income countries.
• Limited diagnostic capabilities and resource constraints in affected regions hinder effective TB control and treatment.
• There is a critical need for robust, sensitive, and affordable detection strategies for TB.

Purpose of the Study:

• To develop and characterize a label-free DNA biosensor for the sensitive and specific detection of Mycobacterium tuberculosis (MTB).
• To utilize commercially available screen-printed electrodes (SPEs) for a cost-effective and accessible diagnostic platform.
• To validate the biosensor's performance using purified DNA and raw clinical samples.

Main Methods:

• Fabrication of a label-free DNA biosensor on screen-printed electrodes (SPEs).
• Morphological characterization using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS).
• Electrochemical analysis via cyclic voltammetry (CV) and differential pulse voltammetry (DPV); DNA hybridization with the IS6110 gene marker.

Main Results:

• The biosensor demonstrated robust, sensitive, and specific detection of MTB via DNA hybridization.
• Satisfactory selectivity was observed against non-target bacteria like Salmonella typhimurium and Escherichia coli.
• Achieved a limit of detection (LOD) of 1.90 nM with high linearity (R² = 0.993) over a 0.5-10 nM DNA concentration range.

Conclusions:

• The developed DNA biosensor provides a promising tool for accurate TB detection.
• The approach is robust, sensitive, specific, and requires minimal sample volume.
• Potential for adaptation into portable point-of-care diagnostic devices for widespread TB screening.