Ultrasensitive Electrochemical Biosensor for the Detection of the mecA Gene Sequence in Methicillin Resistant Strains of Staphylococcus aureus Employing Gold Nanoparticles

Abstract

An ultrasensitive and specific electrochemical biosensor for the determination of mecA gene, which is associated with methicillin resistant strains, was successfully developed. Capture probes were immobilized on the surface of a gold nanoparticle modified glassy carbon electrode. After target probes were hybridized with capture probes, dual labeled gold nanoparticles with alkaline phosphatase and detection probes were hybridized with target probes for sensitive detection of mecA gene fragments. Dual labeled gold nanoparticles, which acted as a high-efficiency signal amplification strategy, were successfully prepared. The gold nanoparticles and dual labeled gold nanoparticles were characterized by transmission electron microscopy. Different concentrations of gene fragments were detected to inspect the specificity and sensitivity of the proposed biosensor. This biosensor displayed outstanding selectivity and a remarkable sensitivity (LOD = 23 pM, S/N = 3). Good linearity over the range of 50 pM to 250 pM was demonstrated. Moreover, the measurement process required less than 2 hours. This device was employed for the successful determination of mecA gene from methicillin resistant Staphylococcus aureus.

Keywords:

• Biosensor
• Differential pulse voltammetry
• Dual labeled gold nanoparticles
• MecA fragments

Notes

^a PNA: Peptide nucleic acid.

^b Lateral flow nucleic acid (LFNA) test strips.

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