Development of an optical biosensor using gold nanoparticles and quantum dots for the detection of Porcine Reproductive and Respiratory Syndrome Virus

Current diagnostic methods to detect Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) have many disadvantages and are ill suited for on-site detection of the highly contagious virus, making effective disease eradication difficult. A novel PRRSV detection method is therefore proposed, which utilizes nanophotonic and optical biosensor technology. The biosensor consists of two labeled biomolecule architectures: a PRRSV-specific capture antibody labeled with a fluorescent dye bound to a protein that is labeled with a quantum dot and a PRRSV-specific capture antibody labeled with a fluorescent dye bound to a protein that is labeled with a gold nanoparticle. When exposed to PRRSV, a binding event between the virus particle and antibody takes place, resulting in a conformational change within the biosensor complex that increases the distance between the fluorescent molecules or the fluorescent/quencher molecules. The resulting change in the fluorescence spectrum of the sensor occurs due to a nonradiative signal transduction method, Fluorescence Resonance Energy Transfer (FRET), between the fluorescent dye and the quantum dot or gold nanoparticle. Results have demonstrated that both sensor architectures are able to rapidly and effectively detect PRRSV in solution with a detection limit of 3 particles/μl, illustrating that the optical biosensor is a feasible method for PRRSV detection.