A disposable gold-cellulose nanofibril platform for SERS mapping.

Area of Science:

• Nanomaterials Science
• Analytical Chemistry
• Biotechnology

Background:

• Accurate and rapid detection of pathogenic bacteria like Escherichia coli (E. coli) is crucial for public health and food safety.
• Current methods for bacterial enumeration can be time-consuming and require specialized equipment.
• Development of sensitive, selective, and cost-effective detection platforms is an ongoing challenge.

Purpose of the Study:

• To develop a disposable and inexpensive paper-like substrate for rapid enumeration of E. coli.
• To utilize surface-enhanced Raman scattering (SERS) mapping for sensitive bacterial detection.
• To establish a fast and reliable method for quantifying E. coli in various samples.

Main Methods:

• Fabrication of a gold nanoparticle-embedded cellulose nanofibril (CNF) substrate.
• Utilizing the substrate as a scavenger for E. coli enrichment.
• Employing antibody-based separation and a sandwich assay with DTNB-coated Au nanorod SERS probes.
• Performing SERS mapping for visual distribution density analysis and quantification.

Main Results:

• The developed substrate enabled rapid E. coli enumeration within one hour.
• A linear correlation was observed between E. coli concentration (15 cfu mL⁻¹ to 1.5 × 10⁵ cfu mL⁻¹) and SERS mapping signals.
• The limit of detection (LOD) for E. coli was determined to be as low as 2 cfu mL⁻¹.
• The method demonstrated high selectivity against other bacterial species (M. luteus, B. subtilis, E. aerogenes).

Conclusions:

• A cost-effective and disposable paper-like SERS substrate was successfully developed for E. coli detection.
• The SERS mapping assay provides a rapid, sensitive, and selective method for bacterial enumeration.
• This approach holds significant potential for applications in food safety and clinical diagnostics.