title: Resolution enhancement for low-temperature scanning microscopy by cryo-immersion.
abstract: Here we report a simple way to enhance the resolution of a confocal scanning microscope under cryogenic conditions. Using a microscope objective (MO) with high numerical aperture (NA = 1.25) and 1-propanol as an immersion fluid with low freezing temperature we were able to reach an imaging resolution at 160 K comparable to ambient conditions. The MO and the sample were both placed inside the inner chamber of the cryostat to reduce distortions induced by temperature gradients. The image quality of our commercially available MO was further enhanced by scanning the sample (sample scanning) in contrast to beam scanning. The ease of the whole procedure marks an essential step towards the development of cryo high-resolution microscopy and correlative light and electron cryo microscopy (cryoCLEM).
authors.forename: Michael
authors.initials: M
authors.lastname: Metzger
authors.forename: Alexander
authors.initials: A
authors.lastname: Konrad
authors.forename: Sepideh
authors.initials: S
authors.lastname: Skandary
authors.forename: Imran
authors.initials: I
authors.lastname: Ashraf
authors.forename: Alfred J
authors.initials: AJ
authors.lastname: Meixner
authors.forename: Marc
authors.initials: M
authors.lastname: Brecht
mesh_terms: D003080:Cold Temperature; D020285:Cryoelectron Microscopy; D005615:Freezing; D018613:Microscopy, Confocal / Q000379:methods*; D008856:Microscopy, Fluorescence; D013048:Specimen Handling; D013696:Temperature