Highly selective and sensitive detection of Staphylococcus aureus with gold nanoparticle-based core-shell nano...

Area of Science:

• Nanotechnology
• Molecular Diagnostics
• Microbiology

Background:

• Staphylococcus aureus is a significant gram-positive opportunistic pathogen causing numerous nosocomial infections.
• Rapid and accurate diagnosis of S. aureus is crucial for effective patient management and infection control.
• Gold nanoparticles (AuNPs) possess unique properties making them valuable tools in diagnostic applications.

Purpose of the Study:

• To develop and evaluate a novel colorimetric method for the detection of Staphylococcus aureus.
• To utilize gold nanoparticles (AuNPs) conjugated with a specific biosensor for enhanced detection.
• To compare the sensitivity and specificity of the AuNP-based method with conventional PCR.

Main Methods:

• Bacterial culture and chromosomal DNA extraction from Staphylococcus aureus.
• Design of primers and biosensors targeting the Protein A gene sequence.
• Polymerase Chain Reaction (PCR) assay, gel electrophoresis, and AuNP-biosensor conjugation.
• Colorimetric detection based on hybridization, evaluated by visual inspection, spectrophotometry, and electron microscopy.

Main Results:

• Agarose gel electrophoresis confirmed a 390 bp band, indicating the presence of the Protein A gene.
• The AuNP-biosensor demonstrated higher sensitivity (10 ng/μL) compared to PCR (30 ng/μL).
• A limit of detection (LOD) of 8.73 ng/μL was achieved, and specificity was confirmed against other bacterial DNA.

Conclusions:

• The developed gold nanoparticle-based colorimetric method provides a rapid and sensitive approach for detecting Staphylococcus aureus.
• This novel diagnostic tool offers advantages in sensitivity and speed over traditional PCR methods.
• The AuNP-biosensor holds significant potential for the routine clinical diagnosis of S. aureus infections.