Illumination of 8a at an activating wavelength () of 360 nm cleaves the nitrobenzyl group to release 8b, which can be irradiated at an exciting wavelength () of 575 nm to emit light in the form of fluorescence. The injection of 8a in goldfish epithelial keratocytes results in the incorporation of this conjugate within intracellular actin microfilaments. Images of the labeled sample that recorded exciting at 4 (a), 81 (b) and 136 s (c) after illumination at of a portion of a keratocyte show a spatial redistribution of fluorescence over time. This change is indicative of microfilament dynamics. The scale bar in (a) corresponds to 10 μm (reproduced with permission from [71]).
