Multiplex DNA biosensor for viral infection diagnosis using SERS molecular sentinel-on-chip
The development of sensitive and selective techniques for multiplex detection of DNA biomarkers is paramount for clinical diagnosis. Various multiplex DNA detection techniques have been reported. However, most of these techniques require multiple incubation and/or washing steps or target sequence labeling. In this work, we demonstrated a unique multiplex DNA biosensor for viral infection diagnosis using the surface-enhanced Raman scattering (SERS) “Molecular Sentinelon- Chip” (MSC) technique. The sensing mechanism is based upon the change of SERS intensity when Raman labels tagged at 3′-ends of molecular sentinel nanoprobes are physically displaced from the Nanowave chip’s surface upon target DNA hybridization. SERS measurements were performed immediately following a single hybridization reaction between the target single-stranded DNA (ssDNA) sequences and the complementary molecular sentinel nanoprobes immobilized on the Nanowave chip without requiring target labeling (i.e., label-free assay), secondary hybridization, or post-hybridization washing, thus reducing the assay time and lowering cost. Two nucleic acid transcripts, interferon alpha-inducible protein 27 (IFI27) and interferon-induced protein 44-like (IFI44L), are used as model systems for the multiplex detection concept demonstration. These two genes are well known for their critical role in host immune response to viral infections and can be used as molecular signature for viral infection diagnosis. The results indicate the effectiveness and potential of the MSC technology for multiplex DNA detection for point-ofcare diagnostics and global health applications.
