Bio-organism sensing via surface enhanced Raman spectroscopy on controlled metal/polymer nanostructured substrates

Area of Science:

• Nanotechnology
• Spectroscopy
• Microbiology

Background:

• Surface-enhanced Raman spectroscopy (SERS) is a powerful technique for molecular detection.
• Developing reproducible and sensitive SERS substrates is crucial for practical applications.
• Current methods for pathogen detection can be time-consuming and require sample amplification.

Purpose of the Study:

• To develop and optimize a new class of nonlithographically prepared SERS substrates.
• To achieve high reproducibility and enhancement factors for SERS detection of microbial pathogens.
• To demonstrate the utility of these substrates for the rapid, selective identification of bacteria and viruses.

Main Methods:

• Fabrication of nanostructured poly(p-xylylene) films metalized with silver (Ag) or gold (Au).
• Optimization of substrates for surface plasmon resonance.
• Application of SERS for spectral fingerprint analysis of bacterial and viral samples.

Main Results:

• Demonstrated high spot-to-spot and sample-to-sample reproducibility of SERS signals.
• Successfully detected and distinguished between different bacterial strains (e.g., E. coli, B. cereus) and viruses (e.g., respiratory syncytial virus, Coxsackievirus).
• Achieved differentiation of Gram-positive vs. Gram-negative bacteria and enveloped vs. nonenveloped viruses.

Conclusions:

• Developed a novel class of SERS substrates based on metalized nanostructured poly(p-xylylene) films.
• These substrates provide a noninvasive, nondestructive method for pathogen identification.
• The developed SERS approach allows for rapid, selective detection of infectious agents without the need for culture amplification.