Visualizing individual microtubules by bright field microscopy

摘要

Since its introduction over 400 years ago,1 the optical microscopenhas proven to be an indispensable tool in biologicalnresearch, providing the means to study a multitude of processesnwithin living cells. The spatial resolution of light microscopynis traditionally limited by diffractionnconsiderations2 to approximately u0001/2 or larger, where u0001 isnthe wavelength of the illumination light. Despite this intrinsicnlimitation, submicroscopic macromolecules u0001with dimensionsnof u000320–200 nmu0002 or assemblies of macromoleculesnthat scatter light weakly can be visualized in isolation u0001thatnis, when separated by distances larger than the resolutionnlimitu0002 by a variety of imaging techniques that rely on fluorescencenor polarization effects to enhance the limited contrast.