SPRi-based adenovirus detection using a surrogate antibody method.

Adenovirus infection, which is a waterborne viral disease, is one of the most prevelant causes of human morbidity in the world. Thus, methods for rapid detection of this infectious virus in the environment are urgently needed for public health protection. In this study, we developed a rapid, real-time, sensitive, and label-free SPRi-based biosensor for rapid, sensitive and highly selective detection of adenoviruses. The sensing protocol consists of mixing the sample containing adenovirus with a predetermined concentration of adenovirus antibody. The mixture was filtered to remove the free antibodies from the sample. A secondary antibody, which was specific to the adenovirus antibody, was immobilized onto the SPRi chip surface covalently and the filtrate was flowed over the sensor surface. When the free adenovirus antibodies bound to the surface-immobilized secondary antibodies, we observed this binding via changes in reflectivity. In this approach, a higher amount of adenoviruses resulted in fewer free adenovirus antibodies and thus smaller reflectivity changes. A dose-response curve was generated, and the linear detection range was determined to be from 10 PFU/mL to 5000 PFU/mL with an R(2) value greater than 0.9. The results also showed that the developed biosensing system had a high specificity towards adenovirus (less than 20% signal change when tested in a sample matrix containing rotavirus and lentivirus).