SOFIA is an apparatus and method for improved optical geometry for enhancement of spectroscopic detection of analytes in a sample. The invention has already demonstrated its proof-of-concept functionality as an apparatus and method for ultrasensitive detection of prions and other low-level analytes.
SOFIA combines the specificity inherent in monoclonal antibodies  for antigen capture with the sensitivity of surround optical detection technology. To detect extremely low signal levels, a low-noise, photovoltaic diode is used as the detector for the system. SOFIA uses a laser to illuminate a microcapillary tube holding the sample. Then, the light collected from the sample is directed to transfer optics from optical fibers. Next, the light is optically filtered for detection, which is performed as a current measurement amplified against noise by a digital signal processing lock-in amplified. The results are displayed on a computer and software designed for data acquisition.
The advantages of such a detection array are numerous. Primarily, it permits the use of very small samples at low concentration to be optimally interrogated using the laser-induced fluorescence technique. This fiber-based detection system is adaptable to existing short-pulsed detection hardware that was originally developed for sequencing single DNA molecules. The geometry is also amenable to deployment for short-pulse laser, single-molecule detection schemes. The multiport geometry of the system allows efficient electronic processing of the signals from each arm of the device. Finally, and perhaps most importantly, fiberoptic cables are essentially 100% efficient in optical transmission, having an attenuation less than 10 dB/km. Thus, once deployed for use in a facility, the fluorescence information can be fiberoptically transmitted to a remote location, where data processing and analysis can be performed.