Colorimetric detection of oral bacteria using functionalized gold nanoparticles as a plasmonic biosensor array

Area of Science:

• Nanotechnology
• Biomedical Engineering
• Microbiology

Background:

• Early detection of oral bacteria is crucial for preventing oral diseases.
• Current detection methods may lack the sensitivity or specificity required for timely intervention.
• Functionalized gold nanoparticles offer a promising platform for novel biosensing applications.

Purpose of the Study:

• To investigate the sensitivity and specificity of functionalized gold nanoparticles for plasmonic sensing of oral bacteria.
• To develop and validate a biosensor array for detecting specific oral bacterial species.
• To correlate gold nanoparticle aggregation with localized surface plasmon resonance (LSPR) shifts for bacterial identification.

Main Methods:

• Synthesis of gold nanoparticles (AuNPs) with varying sizes, shapes, and surface functionalizations (CTAB, MEA).
• Development of a biosensor array utilizing spherical and anisotropic AuNPs.
• Detection of four oral bacterial species (A. actinomycetemcomitans, A. naeslundii, P. gingivalis, S. oralis) using the biosensor array.
• Analysis of plasmonic response via RGB and UV-vis absorbance measurements, correlating with zeta potential and AuNP aggregation.

Main Results:

• The biosensor array successfully detected individual oral bacterial species based on unique plasmonic responses.
• Localized surface plasmon resonance (LSPR) shifts were observed due to AuNP aggregation on bacterial surfaces.
• Sensitivity was found to be dependent on bacterial species, concentration, and AuNP characteristics (shape, concentration, functionalization).

Conclusions:

• Functionalized gold nanoparticles provide a sensitive and specific platform for oral bacterial detection.
• The plasmonic sensing approach based on AuNP aggregation and LSPR shift is effective for identifying oral bacteria.
• This technology holds potential for early diagnosis and management of oral diseases.