Single molecule, two-beam fluorescence cross-correlation spectroscopy (FCCS) will be used as a high-speed chemical analysis tool for the detection and characterization of solution-phase ligand-receptor binding interactions in an array of electrophoresis microchannels integrated on a single microchip. The use of FCCS will enable multicomponent analysis of complex samples continuously flowing through the microchannels, eliminating the need for a chemical separation. This will greatly simplify the microchip design compared to microarrays utilizing separations-based electrophoresis. In particular, the resolution of different analytes will not depend on the length of the electrophoresis channel and will not be effected by the use of extremely short channels. Furthermore, the need for an additional sample injection channel will be eliminated. Thus, these microarrays will consist of a larger number of channels occupying a smaller area of the microchip than is possible with separations-based electrophoresis. The high speed analysis capabilities of FCCS will enable rapid screening in a large number of electrophoresis channels in succession. The research project will be divided into an initial R21 phase and a second R33 phase. In the R21 phase, the application of two-beam FCCS to carry out multicomponent analysis in capillary and microchip electrophoresis systems will be demonstrated. We will utilize these capabilities in the study of DNA-protein and protein-protein binding interactions. In the R33 phase, densely packed arrays of electrophoresis microchannels in planar glass chips, along with integrated fluid handling, electrical, and computer interfaces, will be created. The FCCS analysis technique will be used in combination with sample scanning confocal microscopy to screen large numbers of samples as they flow through the microchannels. Applications for this technology will be in the areas of clinical diagnostics, drug discovery, proteomics research, and environmental monitoring where the development of new chemical analysis tools with high speed, throughput, and sensitivity are extremely important.