FS-7500 Freeze Substitution System

Trouble-free freeze-substitution and low temperature embedding on a routine basis.

Safety

• Built-in high capacity exhaust fan with hose automatically vents substitution chamber when cover removed
• Cryo transfer tool provided to safely & conveniently remove cold sample holders
• Large acrylic work surface with anti-spill lip

Convenience

• LN₂ Dewar can be refilled during a substitution run
• Internal illumination of substitution work chamber automatically activated when chamber cover removed
• Wide variety of specimen holders, baskets & embedding molds
• Low LN₂ coolant consumption
• Programmable data key to store individual substitution protocols
• User friendly digital controller stores up to 10 substitution programs

Results

• N₂ gas booster automatically activated when substitution chamber cover removed to minimize O₂ contamination
• Performs conventional and PLT (Progressive Lowering of Temperature) substitution
• Reliable & repeatable results with 4 temperature soak and 3 temperature ramp settings

Features

• Programmable temperature control for trouble free substitution and low temperature embedding routinely. Performs conventional or PLT (Progressive Lowering of Temperature) substitution automatically.
• Independent temperature control for substitution and polymerization chamber for reliable and reproducible results:
• Substitution chamber temperature from -140C to +70C with +/- 0.1C stability.
• Four holding time settings from 0-999 hours for each.
• Three temperature/time ramp settings.
• User friendly 10 memory programmable process controller for substitution chamber. Programs can be stored on removable “data keys” for safe storage.
• Low LN₂ coolant consumption with the ability to refill the 45 liter Dewar while a substitution is in progress.
• Several specimen holder varieties available for maximum flexibility.

Description

An essential prerequisite for successful cryo-substitution is starting with good cryo-fixation such as double-sided propane jet freezing, metal mirror freezing or high pressure freezing. Successfully cryofixed samples, typically stored in LN₂ are then transferred into the FS-7500 where the substitution solvent is pre-programmed to a temperature below that where secondary ice crystal growth can occur (typically 190K for most biological samples) and above the melting point temperature of the solvent being used.
The FS-7500 uses liquid nitrogen as a coolant to achieve a base operating temperature of -140C (133K) which is well below the ice recrystallization temperature in any biological structure. The temperature of the substitution chamber is set & regulated by the system controller to an accuracy of better than +/- 0.1C over the range from -140C to + 70C

The FS-7500 is a free standing, caster wheel mounted, system with a large, hard acrylic, worktop mounted on to its 45 liter high efficiency LN₂ Dewar. The temperature controlled substitution chamber is conveniently located in the center of the worktop for easy access. The chamber is provided with a viewing port/cover, which is simply lifted off to gain access into the substitution workspace. As it is lifted off, the ventilation system is automatically turned on to extract fumes and the chamber internal illumination is turned on.
Low temperature embedding in methacrylates, such as Lowicryl K4M, is commonly employed in freeze substitution and is accommodated in the FS7500 system with appropriate embedding molds and holders. Polymerization of the resin is generally by long wave UV irradiation for several hours at 240K. It is important during this process to minimize the presence of O₂ in the chamber since O₂ is a very strong inhibitor of the polymerization of the resin. This is achieved in the FS-7500 by an automatic N₂ gas generator, which is turned on whenever the chamber cover is removed. An ultraviolet lamp, with power supply, is provided as standard with each FS-7500 system.
The substitution media is a solvent such as acetone or methanol, which slowly dissolves away and replaces the ice in the frozen specimen. The solvent is placed in commonly used laboratory items such as Eppendorf tubes, scintillation vials, glass cryo vials, Beem capsules, gelatin capsules, etc, which in turn are placed in the FS-7500 specimen holder. A universal specimen holder is provided with the system which accommodates most of these commonly used cryo vials and containers, and a “start up” kit of these consumables is provided with each FS-7500 system.
The specimen holders used with the FS7500 are designed with a large thermal mass to provide good temperature uniformity and stability.

These features combine to make the FS-7500 an extremely convenient to use and versatile Freeze Substitution System.
Features:
Temp Range: -140C to +70C
Temp stability: +/- 0.1C
Coolant: Liquid Nitrogen
Temp Control: Digital microprocessor controller with display of actual and set temp
Programmable: 3 temp/ramp settings 4 hold time settings 0-999 hours
Method: Conventional freeze substitution or PLT (Progressive Lowering of Temp)
Memory: 10 memory channels for storing frequently used freeze substitution protocols
Data Key: 64KB “Data Key” provides unlimited secure program memory for multiple user’s (each user can have personal data key)
Lighting: Built-in LED chamber illumination
Fume Extraction: Extractor fan automatically activated by chamber cover
Oxygen exclusion: N2 gas generator activated by chamber cover
Supplied complete with the following:
Low loss 45 liter liquid nitrogen Dewar on roller base
Large, top access, loading port & freeze substitution chamber
Acrylic solid surface work top with ample working space
Digital microprocessor controller on swivel pod
UV polymerization lamp with power supply
Specimen holder cup with rack
Polymerization holder cup with rack
Cryo manipulator tool
LN2 filling device
Start up consumables package
Specifications:
90-120 Vac 60 Hz or 220-240 Vac 50 Hz power input