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High-Precision Tracking with Non-blinking Quantum Dots Resolves Nanoscale Vertical Displacement

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posted on 11.04.2012, 00:00 by Kyle Marchuk, Yijun Guo, Wei Sun, Javier Vela, Ning Fang
Novel non-blinking quantum dots (NBQDs) were utilized in three-dimensional super-localization, high-precision tracking applications under an automated scanning-angle total internal reflection fluorescence microscope (SA-TIRFM). NBQDs were randomly attached to stationary microtubules along the radial axis under gliding assay conditions. By automatically scanning through a wide range of incident angles with different evanescent-field layer thicknesses, the fluorescence intensity decay curves were obtained. Fit with theoretical decay functions, the absolute vertical positions were determined with sub-10-nm localization precision. The emission intensity profile of the NBQDs attached to kinesin-propelled microtubules was used to resolve the self-rotation of gliding microtubules within a small vertical distance of ∼50 nm. We demonstrate the applicability of NBQDs in high-precision fluorescence imaging experiments.