My bucket list has a few unrealistic things on it, such as “establish a close friendship with an elephant.” When I see how fast imaging technology improves, my goal to “float in a cell with swimmies on my arms” may not be as far off base as finding my BFF pachyderm. Although I may never be able to dive into a cell, I’m willing to bet I can eventually find myself standing in some amazing 3D images of a cell. Today’s image is from a paper describing improved imaging methods that produce super-resolution images that’ll knock your socks off.
Image resolution refers to the ability to distinguish two closely positioned lines or objects. Super-resolution imaging techniques have allowed biologists to see details in small structures, with resolutions down to about 20nm. A group of biologists recently pushed this resolution limit even further, and by doing so, was able to capture images of individual actin filaments with amazing detail. Xu and colleagues improved the 3D STORM (stochastic optical reconstruction microscopy) imaging methods by using two objective lenses to double the amount of fluorescent signal collected off of a cell sample. By imaging individual actin filaments in cells using this dual-objective STORM method, the 3D ultrastructure of the cytoskeleton revealed two layers of actin networks in a sheet-like membrane protrusion. The images above show the distinct organization of each of these two layers, each with a thickness of about 30-40nm. Color coding of the filaments (violet to red) provides a representation of the three-dimensional space (violet actin is closest to the glass coverslip, while red is furthest from the coverslip).
Xu, K., Babcock, H., & Zhuang, X. (2012). Dual-objective STORM reveals three-dimensional filament organization in the actin cytoskeleton Nature Methods, 9 (2), 185-188 DOI: 10.1038/nmeth.1841