The XCell® ATF 2 and 4 Stainless Steel Housings are components of the Repligen XCell® ATF System, designed to support fully scalable bioprocesses through alternating tangential flow (ATF) filtration. This technology utilizes an integrated diaphragm pump to generate pulsating, reversible flow through a hollow fiber filter, which retains large components like cells while removing waste or product components (permeate/filtrate). An additional pump continuously removes cell-free permeate from the system.
Function Description:
The core function of the XCell® ATF Stainless Steel Housings is to facilitate alternating tangential flow (ATF) filtration in bioreactors. The system operates through a two-cycle process: the pressure cycle (P-cycle) and the exhaust cycle (E-cycle). During the P-cycle, pressurized air inflates a silicone diaphragm, moving it towards the pump liquid-side (PL) hemisphere and driving liquid from the diaphragm pump through the hollow fiber filter (HFF) into the process vessel. In the E-cycle, vacuum is introduced, pulling the diaphragm down towards the pump air-side (PA) hemisphere, and drawing liquid from the process vessel back through the HFF into the diaphragm pump. This alternating flow generates tangential flow across the hollow fiber filter in both directions, preventing filter fouling and maintaining high cell viability and productivity.
The XCell® ATF 2 and 4 Housings accommodate different bioreactor scales. The XCell® ATF 2 is designed for smaller bioreactors (2-10 L), while the XCell® ATF 4 is suitable for larger bioreactors (10-50 L). Both housings are made of stainless steel, ensuring durability and compatibility with sterilization processes.
Key Components:
- Filter Housing: XCell® ATF 2 utilizes a fully encapsulated hollow fiber membrane attached above the stainless steel diaphragm pump. XCell® ATF 4 includes a stainless steel housing that holds the hollow fiber filter.
- Diaphragm Pump: A spherical housing containing a silicone diaphragm membrane that is inflated and deflated by pressurized air or vacuum to create alternating flow.
- XCell® ATF to Bioreactor (A2B) Connection Assembly: Tubing assembly connecting the filtration assembly to a bioreactor or process vessel.
- Bioreactor Adapter: An adapter between the connection assembly and the bioreactor port (e.g., Ingold or tri-clamp for glass bioreactors, disposable aseptic connectors for single-use bioreactors). Note: Bioreactor adapter is not provided.
- Hollow Fiber Membrane (HFM) or Hollow Fiber Filter (HFF): Available in 0.2 or 0.5 µm or 50 kD pore sizes, positioned between the bioreactor and the diaphragm pump.
- Filtrate/Harvest Tubing: Sterile tubing and fittings connecting the housing to the collection vessel, compatible with a filtrate/harvest pump. Note: Filtrate/harvest tubing and pump are not provided.
Important Technical Specifications:
- Dimensions:
- XCell® ATF 2 SS Pump Housing: 30" H, 5" W (Nominal footprint: 0.04 m²)
- XCell® ATF 4 SS Pump Housing: 21" H, 8" W (Nominal footprint: 0.13 m²)
- These dimensions are estimates and can vary based on cartridge choice and connection accessories.
- Bioreactor Size Compatibility:
- XCell® ATF 2: 2-10 L
- XCell® ATF 4: 10-50 L
- Tubing Set Kits:
- XCell® ATF 2 tubing set kits (e.g., ATF2-A2B-TC, ATF2-A2B-RMTC, ATF2-A2B-TCAQ, ATF2-A2B-AQ) offer tri-clamp, ReadyMate™, AseptiQuik® connections.
- XCell® ATF 4 tubing set kits (e.g., ATF4-A2B-TC, ATF4-A2B-TCAQ) offer tri-clamp and AseptiQuik® connections.
- All tubing set kits have a pressure rating of 25 psi.
- Materials of Construction (for accessories):
- Top permeate and drain tubing: Platinum-cured silicone (1/4" ID)
- Dip tube: 316 L SS (3/8" ID)
- Pressure sensor kit: Polycarbonate (3/8" ID)
- Sound Levels: Repligen XCell® ATF System is rated for acceptable sound levels (60 dBA).
Usage Features:
- Scalability: Two housing sizes (ATF 2 and ATF 4) support a range of bioreactor volumes, from 2 L to 50 L.
- Filter Preparation: The assembled housing requires wetting, integrity testing (pre- and post-autoclaving), and autoclaving before use.
- Connection to Bioreactor: Fluid management involves retentate (A2B) tubing set kits and accessories that connect the housing to the bioreactor. The bioreactor end of the tubing can be tri-clamp, AseptiQuik®, or ReadyMate™ disposable aseptic connectors.
- Hollow Fiber Filter Installation: Both XCell® ATF 2 and 4 Housings accommodate various hollow fiber modules. Proper alignment with sanitary gaskets and secure clamping are crucial for effective operation.
- Diaphragm Installation: The silicone diaphragm must be correctly oriented and seated to prevent premature failure. It is designed for over one million pressure/exhaust cycles when used as instructed and with aqueous liquids only.
- Autoclaving: The stainless steel housing assembly can be autoclaved using a pre-programmed liquid cycle at 121°C for 30 minutes. For ATF 4, the procedure includes three pre-vacuum pulses to ensure sterility and filter integrity.
- Pre-autoclaving Integrity Testing: Strongly recommended to ensure proper assembly before autoclaving.
Maintenance Features:
- Diaphragm Replacement: The silicone diaphragm must be replaced after each run and prior to sterilization.
- Disassembly: Procedures are provided for removing the housing from the bioreactor, disconnecting pneumatic and sensor connections, and disassembling the filtration assembly.
- HFF Removal: Instructions for removing the hollow fiber filter, including opening clamps, removing O-rings, and pressing the HFF in the opposite direction to remove.
- Decontamination: For disposal, the HFF should be rinsed two times with water to remove residual cells and debris, followed by decontamination with 0.5M NaOH, potassium hydroxide, or bleach for 2-24 hours. A 5.25% chlorine solution (household chlorine bleach) is recommended at 5000-6000 ppm for initial decontamination of organic spill material, and 500-600 ppm for disinfection of cleaned surfaces.
- Annual Safety Inspection: Includes visual inspection for damage, vacuum system leak assessment, air filter replacement, inspection of air and vacuum connections, and pressure hold test of the XCell® ATF Device.
- Spare Parts: Comprehensive lists of spare parts are provided for both XCell® ATF 2 and 4 systems, including pump hemispheres, clamps, gaskets, filters, tubing, and other accessories.
- Transportation: The Pneumatic Enclosure weighs 20 kg (44 lbs), requiring care during lifting and transport, with the use of a cart recommended.
- CE Regulations: XCell® ATF 2 and 4 Devices are assessed for CE regulations under applicable Machinery Directives, Essential Health and Safety Requirements, Low Voltage Directive, Electromagnetic Compatibility Directive, and Pressure Equipment Directives. A Declaration of Conformity letter is included with the equipment.
- California Proposition 65 Warning: The product may expose users to chemicals including lead, which can cause cancer and birth defects or other reproductive harm. Further information is available at www.P65Warnings.ca.gov/product.
Need help?
General
To Next Page
