Detection of rotavirus in clinical specimens using an immunosensor based on the principle of fluorescence fluctuation spectroscopy

Rapid detection of viruses and bacteria in clinical specimens is important for the prevention of epidemics. In this study, we developed a sensitive fluorescence sensor that can detect small, fluorescence-labeled particles dispersed in a solution. The system comprises a laser confocal optical system and a mechanical sample stage. The laser generates fluorescence fluctuations from small particles in a sample droplet on the sample stage. The optical system collects this epifluorescence data with a highly sensitive photomultiplier tube. A prototype detected particles within a few minutes in sample volumes smaller than 20 μL. To examine the feasibility of using this immunosensor as a diagnostic tool, assemblages of rotavirus and fluorescence-labeled antibody were analyzed. The detection sensitivity for rotavirus was 1 × 10 4 pfu/mL. Rotavirus in stool samples from patients with acute gastroenteritis was also detected. We evaluated the advantages and disadvantages of the immunosensor in comparison with ELISA and RT-PCR, which are considered to be the gold standards for virus detection.