High Spatial and Temporal Resolution Velocimetry Measurements for Microfluidic Devices

Physical Sciences Inc. (PSI) and Brown University propose to develop and demonstrate a system for the measurement of fluid velocities in close proximity fo solid surfaces in microfluidic and micropropulsion devices. The instrument couples the Total Internal Reflection Fluorescent Microscopy (TIRFM) technique with Particle Tracking Velocimetry (PTV) algorithms and integrates waveguide optical coupling for depth-tailored excitation at the sub-micron scale range, high efficiency quantum dot fluorescence probes for ~ nm spatial resolution, and compact, low-cost photonic excitation sources such as pulsed LEDs. The Phase I research effort will optimize each element of the excitation and collection system, and demonstrate the integral system in a microfluidic channel with improved spatial and temporal resolution compared to existing techniques. The results of the Phase I will be packaged in a set of microfluidic diagnostic systems in Phase II for wall velocity measurements in micro- and nano- scale devices. Extensive testing during the Phase II program will fully validate the sensor's performance, accuracy, and spatial resolution.