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.

V-shaped substrate for surface and volume enhanced Raman spectroscopic analysis of microplastics

Research on the microplastics(MPs)is developing towards smaller size,but corresponding methods for the rapid and accurate detection of microplastics,especially nanoplastics still present challenge.In this work,a novel surface and volume enhanced Raman spectroscopy substrate was developed for the rapid detection of microplastic particles below 5μm.The gold nanoparticles(NPs)were deposited onto the surface and into the V-shaped nanopores of anodized aluminum oxide(AAO)through magnetron sputtering or ion sputtering,and then AuNPs@V-shaped AAO SERS substrate was obtained and studied for microplastic detection.SERS performance of AuNPs@V-shaped AAO SERS substrate was evaluated through the detection of polystyrene and polymethyl methacrylate microspheres.Results indicated that individual polystyrene sphere with a diameter of 1μm can be well detected on AuNPs@V-shaped AAO SERS substrate,and the maximum enhancement factor(EF)can reach 20.In addition,microplastics in ambient atmospheric samples were collected and tested to verify the effectiveness of the AuNPs@V-shaped AAO SERS substrate in the real environment.This study provides a rapid,economic and simple method for detecting and identifying microplastics with small size.