Oils are widely used in crystallography – as cryoprotectants when samples are flash cooled, and as barriers to the dehydration, solvent evaporation, and oxidation, that may occur in air near and above room temperature. The ice ring seen in the diffraction pattern of flash cooled protein crystals arise primarily from crystallization of the aqueous solution surrounding the crystal, not of the internal solvent. Oils can displace and replace this surrounding solution with little risk of damage due to osmotic shock.
Substantial dehydration-induced damage can easily occur between removed from a drop and flash cooling. Dehydration can be minimized by first transferring to an oil drop (using MicroSieve™, in MicroTool kit 1 and MicroTool Kit 2) before mounting the oil coated crystal on a MicroMount or Micromesh.
However, surrounding oil scatters X-rays, reducing diffraction signal-to-noise, and contributes thermal mass that reduces crystal cooling rates and increases the need for penetrating cryoprotectants. These problems are especially acute for the smallest crystals. When mineral oil, Paratone Oil and other high viscosity oils are used, the volume of surrounding oil can exceed the crystal volume by a factor of 10 or more., and can contribute excess drag that increases sample motion in a cryostream. For larger rod or plate shaped crystals, the surrounding oil exerts stresses when it freezes that can cause crystal cracking and mosaic broadening.
LV CryoOil™ Is the best solution to your oil needs. It has the lowest viscosity of any available perfluoropolyether oil (1/10 that of Paratone oil and compatible to that of vegetable oil) and very low surface tension (less than 1/3 that of water). Consequently, a dip in this oil followed by gentle tapping to shake off excess can yield protective oil films on your crystals of as little as 10 µm thick.
LV CryoOil™ has extremely low vapor pressure, excellent chemical inert and excellent thermal stability.
LV CryoOil™ comes in each vial 1.5 ml, enough to protect hundreds of crystals.