Efficient V-Shaped Substrate for Surface and Volume Enhanced Raman Spectroscopic Analysis of Bioaerosol: Prevention from Potential Health Risk

Bioaerosols pose a great threat to human life and health, and developing highly efficient and accurate identification and analysis methodologies for bioaerosols provides prerequisite knowledge to evaluate their toxicity on human health. In this paper, a rapid and economical method is proposed for the detection of bioaerosols based on surface-enhanced Raman scattering (SERS). The SERS substrate was prepared using an anodic aluminum oxide (AAO) template with an inverted conical (V-shaped) nanopore array structure that was subsequently deposited with Ag nanoparticles (AgNPs) through magnetron sputtering. This tailored nanostructure essentially enables the differentiated and efficient detection of Escherichia coli and Staphylococcus epidermidis health risks within 10 min, along with corresponding detection limits of 10³ cells/mL and 10⁴ cells/mL, respectively. Notably, by comparing the Raman spectrum of the two bacteria obtained from the plain plane deposited with the same AgNPs, the V-shaped nanopore array structure provides a more robust enhancement effect in the Raman signal relative to the ordinary plane. More importantly, the applicability of developed AgNPs@V-shaped AAO SERS substrate was validated using ambient bioaerosols, thus emphasizing the great potential of the application of SERS-based technique for a cost-effective, rapid label-free and culture-free bioaerosol analysis without experiencing conventional time-consuming and laborious incubation processes.