Zinc-doped MgO nanohybrids enable sensitive Salmonella typhimurium biosensing

Area of Science:

• Nanomaterials Science
• Biosensor Technology
• Food Safety Analytics

Background:

• Food-borne pathogens like Salmonella Typhimurium present significant food safety and public health risks.
• Current diagnostic methods often lack the required speed, sensitivity, or reliability for real-time monitoring.
• Development of advanced biosensing platforms is crucial for effective pathogen detection.

Purpose of the Study:

• To fabricate and characterize a nanostructured zinc-magnesium oxide (Zn-MgO) based electrochemical DNA biosensor.
• To evaluate the biosensor's performance for the specific detection of the Salmonella invA gene.
• To assess the biosensor's potential for rapid and sensitive detection of Salmonella Typhimurium in food samples.

Main Methods:

• Fabrication of a nanostructured Zn-MgO material for bioelectrode construction.
• Physicochemical characterization of the nanostructure and probe DNA immobilization.
• Electrochemical impedance spectroscopy and cyclic voltammetry for performance evaluation.
• Testing for sequence specificity, dynamic range, sensitivity, and stability.
• Validation using spiked milk samples for Salmonella Typhimurium detection.

Main Results:

• Uniform nanostructure formation with efficient probe DNA immobilization and high surface coverage confirmed.
• Electrochemical analysis showed diffusion-controlled charge transfer and high sequence specificity.
• Achieved a wide linear dynamic range (0-150 aM), high sensitivity (3.22 pA·aM⁻¹), and ultra-low LOD (0.21 aM).
• Demonstrated excellent stability (>85% activity after 60 days) and rapid response time (<5 s).
• Successfully detected Salmonella Typhimurium in milk samples with high sensitivity and minimal matrix interference.

Conclusions:

• The Zn-MgO nanohybrid bioelectrode is a robust, selective, and stable platform for DNA biosensing.
• The synergistic properties of Zn and MgO enhance immobilization and electron transfer for ultrasensitive detection.
• The biosensor exhibits strong translational potential for real-time food safety monitoring and pathogen control.
• This technology offers a promising solution for rapid, sensitive, and reliable diagnostics in food, water, and clinical applications.