Multiplex immunoassays of plant viruses based on functionalized upconversion nanoparticles coupled with immunomagnetic separation

A sensitive, specific and rapid method for the detection of three different kinds of plant viruses including tomato ringspot virus (ToRSV), bean podmottle virus (BPMV) and arabismosaic virus (ArMV) was demonstrated using novel upconversion nanoparticles (UCNPs) as a fluorescence marker coupled with immunomagnetic separation. Magnetic nanoparticles (MNPs, ∼100 nm) were coated with different antibodies were employed to capture and enrich the target viruses. Then antibody-conjugated UCNPs as signal probes were added to form sandwich complexes. This was followed by a fluorescence measurement using a 980nm laser. This method not only avoids the difficulty in simultaneous detection of multiple independent organic fluorphores that require distinct excitation wavelengths, and auto-fluorescence of biological samples due to the higher-energy excitation of QDs but also amplifies detection signal by UCNPs-tags together with easy separation of samples bymagnetic forces, demonstrating the potential to be used for detecting virus in the field of environmental safety and other fields.