We present the theory and experimental validation of a particle tracking velocimetry algorithm developed for application with nanometer-sized tracer particles such as fluorescent molecules and quantum dots (QDs). Traditional algorithms are challenged by extremely small tracers due to difficulties in determining the particle center, shot noise, high drop-in/drop-out and, in the case of quantum dots, fluorescence intermittency (blinking). The algorithms presented here determine real velocity distributions from measured particle displacement distributions by statistically removing randomly distributed tracking events. The theory was verified through tracking experiments using 54 nm flourescent dextran molecules and 6 nm QDs.

Volume Subject Area:
Fluids Engineering
Topics:
Particulate matter, Quantum dots, Algorithms, Displacement, Fluorescence, Noise (Sound)
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