Molybdenum Trioxide Nanocubes Aligned on a Graphene Oxide Substrate for the Detection of Norovirus by Surface-Enhanced Raman Scattering

Abstract

A novel biosensing system based on graphenemediated surface-enhanced Raman scattering (G-SERS) using plasmonic/magnetic molybdenum trioxide nanocubes (mag-MoO 3 NCs) has been designed to detect norovirus (NoV) via a dual SERS nanotag/substrate platform. A novel magnetic derivative of MoO 3 NCs served as the SERS nanotag and the immunomagnetic separation material of the biosensor. Single-layer graphene oxide (SLGO) was adopted as the 2D SERS substrate/capture platform and acted as the signal reporter, with the ability to accommodate an additional Raman molecule as a coreporter. The developed SERS-based immunoassay achieved a signal amplification of up to ∼10 9 -fold resulting from the combined electromagnetic and chemical mechanisms of the dual SERS nanotag/substrate system. The developed biosensor was employed for the detection of NoV in human fecal samples collected from infected patients by capturing the virus with the aid of NoV-specific antibody-functionalized magnetic MoO 3 NCs. This approach enabled rapid signal amplification for NoV detection with this biosensing technology. The biosensor was tested and optimized using NoV-like particles within a broad linear range from 10 fg/mL to 100 ng/mL and a limit of detection (LOD) of ∼5.2 fg/mL. The practical applicability of the developed biosensor to detect clinical NoV subtypes in human fecal samples was demonstrated by effective detection with an LOD of ∼60 RNA copies/mL, which is ∼10 3 -fold lower than that of a commercial enzyme-linked immunosorbent assay kit for NoV.

3D hierarchically porous magnetic molybdenum trioxide@gold nanospheres as a nanogap-enhanced Raman scattering biosensor for SARS-CoV-2

“…In Figure 3h, the XPS wide scan of MoO3-PDA NS (blue spectrum) shows the characteristic peaks of Mo 3d, C 1s, Mo 3p, O 1s, and N 1s. In addition to the elements mentioned above, the XPS wide scan of mag-MoO3-PDA@Au NS (red spectrum) shows additional peaks at 83.9 eV and 706.8 eV, attributed to Au 4f and Fe 2p, respectively 3,35 . The Gaussianfitted high-resolution XPS results are further presented in Figure 3i.…”

“…The ultimate goal is to develop material substrates and/or processes with exceptional qualities to generate reproducible and stable Raman signals 1,2 . With this in mind, metal Au and Ag nanoparticles (NPs) with sophisticated morphologies and dimensions, such as cubic, octahedral, and star-shaped nanostructures, have been introduced into SERS detection technology [3][4][5] . This is due to the propensity of nanostructures with complex morphologies to resonantly couple to light with an intense scattering at the nanoscale, resulting in increased electromagnetic (EM) field strength for "hotspots" generation 6,7 .…”

Two-dimensional material-based virus detection

“…. Similar to the use of MoO 3 QDs in fluorescence sensor [112], the plasmonic and magnetic MoO 3 (mag-MoO 3 ) nanocubes were also utilized in graphene-based SERS immunoassay for the detection of norovirus (NoV) due to their plasmonic SERS enhancement and magnetic separating capacity [122]. As shown in Figure 6, NoV-specific antibody was functionalized on the mag-MoO 3 nanocubes and served as both nanotag in SERS detection and the active material in the immunomagnetic separation.…”

In situ food-borne pathogen sensors in a nanoconfined space by surface enhanced Raman scattering

“…They served as the signal reporter and were able to accommodate an additional Raman molecule as a co-reporter. Attributing to the applied magnetic-based separation process, norovirus was concentrated and identified in clinical samples with the favorable detection range of 10 2 to 10 6 RNA copies/mL [125].…”