Olympus 10x for two-photon microscopy
Olympus released a suite of new objectives this year, and one of them is this 10x/0.6 NA. This is probably the longest focal length (180/10 = 18 mm) objective you can get and use with a standard two-photon system and see activity in single neurons.
0.6 NA might not be enough for tissue bulk labeled with OGB-1, but for GECIs like GCaMP6, signals from single cells are easily resolved. The supplement to the recent Lecoq et al. paper has some analysis of how relatively moderate NAs can yield single cell resolution. Some commercial rigs underfill the 16x/0.8 NAs already, and are probably using something more like 0.6-0.7 NA already.
The field of view isn’t going to be 3.5 mm wide, of course. That takes more extensive customization. But for conventional systems, this objective is probably the best bet. Albeit a 5-figure bet.
great product but the FN is smallish..
…I just ‘tested’ it (sorry – I had no time to be quantitative):
The FOV is quite good. I did not measure the exact field size at my scope but what I saw fits well with a calculated 1.44x larger FOV than that of the Nikon 16x (~1.3mm at my TL Bscope1. This is calculated. Not measured – the long working distance kept me from doing that quickly using a cal., slide with fluorescin solution and I was too lazy to remove my IR blockers).
Cellular GCaMP imaging at this FOV absolutely possible. Judging from the crsip cell borders and black nuclei the PSF wasn’t bad at all.
But I have to say that it’s rather impractical for this particular purpose:
8mm (immersed) working distance is tough to deal with. Yes: one can use ultrasound gel at 100% conc. but even then it’s very easy to lose proper immersion. Making a big well is a possibility, of course, but using a patch pipette will be a pain.
Also: the back aperture is even larger than that of the 16x. Filling it properly will be hard and you need an unconventional m34 0.75 mount – even larger than the m32 0.75 of the Nikon.
So my opinion is: If you plan to buy an objective that’s good for clear brain imaging (that’s what it was actually made for) or you _really_ need a somewhat larger FOV with cellular resolution, go for it. In all other cases I would prefer the Nikon 16x (and potentially get 2 for the same price).
Have the opportunity to test the latest version of this objective (XLPLN10XSVMP) and need to make an adapter. For anyone else in this situation: the threading is M34x1.0.
The above comment states M34x0.75, but that didn’t work for me – perhaps I have an updated version of the objective with a different thread?
… an ‘edit’ function would be nice to kill those nasty typos…
Unfortunately, I don’t have time to configure that at the moment.
Workaround: If you submit a new comment with the typos fixed and tell me to delete the old comment and just keep the new version, that takes me about 5 seconds.
no problem.
By the way: make that _four_ 16x for the price of _one_ 10x.