We have in the past year successfully demonstrated that interference reflection microscopy can image microtubules without relying on fluorescence labeling (see G. Saper and H. Hess*: “Kinesin-propelled label-free microtubules imaged with interference reflection microscopy”, New Journal of Physics, 22, 095002, 2020). This advance enables us to exclude a degradation pathway: degradation resulting from exposure to the intense fluorescence excitation light. In previous experiments, we aimed to control for this degradation pathway. Now a student can conduct and analyze experiments where this degradation pathway is entirely absent. Secondly, we found that the use of unlabeled tubulins results in longer, faster gliding microtubules. Thus, a student can explore the hypothesis that these microtubules have fewer defects and degrade slower, providing an interesting test case for the insights obtained from the study of fluorescently labeled microtubules.
