We got a chance to try out a cool new label-free microscope from NanoLive: the 3D Cell Explorer. It works on a holographic tomography, by rotating a laser beam around the top of the sample and records many transmitted-light images. It then uses software to reconstruct the image with phase and even 3D information. The small index differences of different organelles or regions of the cell results in different retardation of the phase of the transmitted light; in the reconstruction, these areas can be false-colored to give beautiful renderings of cells … all without fluorescent labeling.
We used the Nanolive to watch Naegleria amoeba crawling across a glass surface. These cells move orders of magnitude faster than fibroblasts (20 um/min), so imaging their movement is a serious challenge for many high-resolution microscopes.
The above video is false-colored for different index ranges. It is super cool to see the pseudopods in 3D, and possibly even distinguish the plasma membrane from the actin cortex. The demo went well and it took only about 15 min to take the microscope out of the box and start imaging.
When we demoed the beta version a year or so ago, and it had trouble imaging crawling amoebae: the background subtraction was manual and flaky and the frame rate was too slow. But Nanolive let us try it again after the actual release of the product and things works way better. The background subtraction is now automated and robust, and the frame rate was high enough to watch these fast crawling cells.
I think that this microscope would be a great choice for researchers studying organisms that are not genetically tractable or otherwise cannot be fluorescently labeled. Or for anyone studying organelles that show up with a different index (Naegleria ended up having relatively low-contrast organelles compared to adherent mammalian cells, for instance.)
- affordable (about the cost of an EMCCD camera)
- low intensity (no phototoxicity or photobleaching)
- simple and user-friendly: easier that setting up DIC in Koehler illumination :)
- small footprint and easy setup
- software is free
- potential for beautiful and amazing data
- not versatile: it does one thing (but does that one thing well)
- limited to samples with wide top, like a 35 mm dish (not 96-well plates), because the laser beam comes in at an angle
- 3D information on top and bottom of cells is less impressive
Go check it out!