Quantum dots (QDs) have proved to be invaluable fluorophores across many in vitro microscopy applications because of their greater photostability and brightness than organic dyes and fluorescent proteins. However, commercially available QDs are ~20 nm in diameter due to their bulky passivating layer, which is prohibitively large for use in small or confined systems. We developed a wrapping and functionalizing procedure of hydrophobic QD core-shells. Our QDs have similar brightness and water solubility to commercially-available dots and their size (6-12 nm in diameter depending on emission wavelength) is comparable to that of GFP. Development of small quantum dots enabled us to study the stepping mechanism of kinesin using two different colors at high spatiotemporal resolution. These studies provided further insight into the coordination mechanism between the two kinesin heads during processive motility. We anticipate that our small QDs will provide to high signal to noise measurements in a diverse range of systems currently inaccessible via bulky hydrophilic quantum dots.

Small quantum dot probes for single-molecule studies of motor proteins

248th National Meeting (2014)

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