Saliva presents a minimally invasive alternative medium to blood for performing diagnostics<sup>1</sup>. Microsphere sensors for ions, small organic molecules, and proteins are currently being developed and optical microarrays containing thousands of these sensors will be used for simultaneous multi-analyte analysis. The fiber bundle platform in use is 1mm in diameter and contains approximately 50,000 individually addressable 3.1μm fibers, each with an etched well capable of housing a single 3.1μm microsphere sensor. Micron-sized bead-based chemistries are produced in house, followed by deposition onto a fiber-optic bundle platform, allowing for multiplexed analysis. The ultimate goal is to develop a universal diagnostic system using saliva as the diagnostic medium. This platform will permit multiplexed analysis of a sample by integrating microfluidics with the optical arrays loaded with sensors capable of detecting relevant biomarkers associated with a wide range of disease states.
Disease states that are currently under investigation include end stage renal disease (ESRD) and Sjoegrens Syndrome (SS).
A cell array biosensor was developed, composed of thousands of individual bacteria cells expressing a reporter gene that responds to the presence of environmental pollutants. The single cell array was produced by immobilizing the cells on an optical imaging fiber. A high-density array of microwells was fabricated on the optical imaging fiber's distal face by selectively etching the individual fibers cores. Each microwell was used to accommodate a single living bacterium, allowing simultaneous monitoring of the genetic responses of all the cells in the array. The optical imaging fiber cell array platform provides a powerful tool for the fabrication of whole cell biosensors for various environmental and industrial applications.