2.6. Nanocapsules’ visualization
For the cryoSEM imaging a droplet of capsules suspension was put on the cold sample holder. Then the holder was attached to the transfer rod and immediately immersed (frozen) in liquid nitrogen using Quorum PPT2000 cryo-preparation stage (Polaron, Quorum Technologies, United Kingdom). The holder with the frozen sample was cryo-transferred at the temperature of liquid nitrogen vapors to the chamber of the cryo-unit where the sample was subjected to sublimation at −70◦C for 15–30 min. (until all visible ice crystals disappeared). The sample was then sputter coated with platinum (5 nm thickness). Following coating, specimen was transferred to Fig the cooled stage