Signal “Off-On” Biosensor Based on Fluorescence Resonance Energy Transfer (FRET) for Detection of Sorghum Mosaic Virus

A fluorescence off-on method for the detection of Sorghum mosaic virus (SrMV) based on fluorescence resonance energy transfer (FRET) was developed in this study. The biosensor was realized by the adsorption of SrMV coat protein (CP) on gold nanoparticle (AuNP) and conjugation of anti-SrMV antibody (Ab) on cadmium telluride quantum dot (CdTe QD). The optimum quenching efficiency was about 50% obtained at a CdTe QD-Ab/AuNP-CP ratio of 1:7. Moreover, the feasibility of the developed biosensor was verified by the detection of purified CP and the limit of detection was estimated as 0.02 μg/mL. This strategy was also successfully applied to monitor SrMV CP in plant sap with a recovery rate between 97.7 and 107.4%. The developed biosensor is a simple, rapid, and efficient technique which does not need excessive washing and separation steps.