Rapid and sensitive detection of 4-ethylbenzaldehyde by a plasmonic nose

Abstract Rapid and sensitive detection of volatile organic compounds (VOCs) is essential for environmental monitoring and disease diagnosis. Surface-enhanced Raman scattering (SERS) has a natural analyte recognition ability and can realize ultra-sensitive detection. Herein, we report a plasmonic nose based on a 3D-microneedle array coated with Ag nanoparticles for fast and ultrasensitive SERS detection of VOCs vapor. Since the surface of the 8.3 μ m high microneedle is completely covered by ‘hot spots’, which can effectively slow down the diffusion of gas molecules, so as to ensure that the gas molecules are in full contact with ‘hot spots’, and then detected by the plasmonic nose. Experiments for gaseous 4-methylbenzenethiol detection with a fast responding time (as short as 1 s) are realized, and gaseous 4-ethylbenzaldehyde as a lung cancer marker is also captured with a 10 ppb limit of detection. The results demonstrate that the plasmonic nose is of great potential for environmental monitoring and disease diagnosis.