Development and Initial Evaluation of a Sers-Based Rvfv Assay

Rift Valley fever (RVF) has been a long-recognised veterinary disease of livestock in Africa and can result in dire economic impact causing high morbidity and mortality in domesticated livestock such as cattle. This mosquito borne zoonotic disease is caused by the Rift Valley fever virus (RVFV); Bunyaviridae: Phlebovirus. Surface Enhanced Raman Spectroscopy (SERS) has shown potential in disease detection without the prerequisites presented by the current RVF diagnostic assays. This paper reports on the application of SERS in the development of diagnostic probes for detection of RVFV. RVFV recombinant nucleocapsid protein (rNp) was immobilised on a SERS substrate and used to capture RVFV antibodies. Subsequently, a SERS immunoprobe, which consists of gold nanoparticles (AuNPs) labelled with an antibody binding protein A (SpA) and a Raman reporter 4-mercaptobenzoic acid (4-MBA) was bound to the tested RVF antibodies forming AuNP/SpA/MBA hybrids. The sensitivity of the SERS probes in the detection of RVFV was tested using varying concentrations of the RVFV antibodies. The probes exhibited sensitivity towards RVFV antibodies with a detection limit of 1µg/ml, showing the potential of the SERS platform in the quantitative diagnosis of the RVF virus.