Non-labeled virus detection using inverted triangular Au nano-cavities arrayed as SERS-active substrate

Virus detection is frequently based on antibody-based arrays and polymerase chain reactions. However, these methodologies have time-consuming incubation steps and obtaining clearly isolated target species is a complex process. In the present study, inverted triangular Au nano-cavities with various indentation depths and tip-to-tip displacements are well arrayed as a substrate for qualitative virus detection. The substrate is competent to entrap size-comparable target virus into nano-cavities, which as one, exerts its activity to form surface-enhanced Raman scattering particularly by the edges and cavities of the substrate. Through the induction of the electromagnetic effect by the substrate, the virus can be distinguished from the amino acids on its surface. The detectable concentration for encephalomyocarditis virus or adenovirus is 106 PFU/ml and that for influenza virus is 104 PFU/ml. The tailored substrate is enabled for fast-screening detection of target virus.