Syringe Filters for Cell Culture Whether you are analyzing a human, animal or plant cell culture in the laboratory, field or for research, it’s important to select the correct syringe filter for your cell culture application to ensure optimal performance and avoid contamination, sample leakage, binding and clogging. The purpose of the syringe filters should be to create a stable environment to ensure the validity of your results. When purchasing syringe filters for cell culture, you need to take into consideration five factors: syringe filter connections, material, pore size, diameter, and sterility. These factors will ensure you are using the proper syringe filter for the cell culture application you are conducting. This article will help you determine which cell culture syringe filter to purchase to avoid filter breakage, or inaccurate results. Choosing a Connection Type Syringe filter connections come in two types: double luer lock and luer lock/luer slip. A double luer lock provides a more secure and firmer connection and typically consists of a female luer lock inlet and a standard male luer lock outlet. A double luer lock connection is typically used for applications that need in line filtration for high throughput. Most commonly syringe filters are produced with female luer lock and male luer slip fittings which provide a leak tight connection and can be used for different applications, including liquid filtration. This type of connection is generally for laboratory use. Choosing a Material for Cell Culture The material of the syringe filter is probably the most important factor when doing a cell culture. It must be compatible with the characteristics of your cell culture and the solutions in which it comes into contact. The correct filter material addresses such performance considerations as: Flow Volume capacity/throughput Clogging Impurities leaching into filtered solutions Chemical compatibility Protein binding and extractables to prevent sample contamination There are 14 options for syringe filter material. Here is an overview of them and their characteristics to help you choose the proper syringe filter membrane for your cell culture application. Cellulose Acetate (CA) – Very low protein binding membrane, should not be used with organic solvents; Glass Fiber – Filters high particulate samples, tolerant to most solvents, should not be used with benzyl alcohol; Nylon – Strong mechanical strength and thermal and chemical stability, very low in extractables, should not be used with acids, protein samples, or aggressive halogenated hydrocarbons; Polyethersulfone (PES) – Very low protein binding, good heat resistance, high flow, should not be used with acids, esters, ketones, and aromatic or halogenated hydrocarbons; Polypropylene (PP) – Low protein binders, chemically resistant; Polytetrafluoroethylene (PTFE), and Hydrophilic PTFE – Good thermal stability, low extractable, chemically resistant, prewetting required when used with aqueous samples; Polyvinylidene Fluoride (PVDF) and Hydrophilic PVDF – Low protein binder, broad chemical compatibility, should not be used with bases, ketones, ethers, esters, and certain strong acids; Regenerated cellulose (RC) – Very low protein binder, resistant to hydrophilic solvent, should not be used with strong acids, THF, and chloroform. To help you choose the proper syringe filter material for your cell culture, refer to this guide: If you’re looking for: Then use: Low protein binder for tissue culture media filtration, biological samples, and aqueous samples CA, PES, PP, Hydrophilic PVDF, or RC Chemical compatibility PTFE or Nylon Aggressive organic solvents PP or PTFE Sterile filtration CA, PES, or RC Transducer protectors PTFE Use with most high-performance liquid chromatography (HPLC) samples Nylon High particle load handling Glass Fiber Filtering of proteins, nucleic acids PES or PVDF Low binding membrane for protein-rich solutions PVDF Fast flow and low binding PES High temperature liquids PES Recover of DNA from biological samples Glass Fiber Dissolution testing Glass Fiber Air filtration Glass Fiber, PTFE General laboratory filtration Nylon Nonspecific binding applications RC Non-sterile Nylon, RC Choosing a Pore Size Pore size options are typically 0.05 µm, 0.10 µm, 0.22 µm, 0.45 µm, 0.70 µm, 0.80 µm, 1 µm, 3 µm, 5 µm, and 10 µm. The pore size needed for your syringe filter is typically dictated by your objective or application, so consider what particles you want to eliminate and what you want to capture for your cell culture. For most laboratory applications, a 0.2um or 0.22um pore size is sufficient for most media sterilization, as well as for bacteria and other particle removal larger than 0.2um in diameter. However, if you need to remove larger or a wider range of bacteria, or particles more than 0.45um in diameter, look for a syringe filter with a 0.45um pore size. For particles greater than 0.8um in diameter or to remove yeast and fungi spores, use a syringe filter with a 0.8um pore size. Choosing a Diameter Typically, syringe filters are available in the following diameters: 4mm, 13mm, 17mm, 20mm, 25mm, 30mm, and 33mm. The diameter of the syringe filter dictates the volume of fluid the filter can handle. Adequate volume capacity ensures proper throughput to quickly and efficiently process your entire cell culture sample. Choosing the proper filter size is crucial to avoid rupturing the syringe filter’s housing. As a guide, if the volume of fluid to filter is: 5 to 1.0 ml, then use a 4mm syringe filter; 2-10 ml, then use a 13mm syringe filter; 10-100 ml (or up to 200 ml with a prefilter), then use a 25mm syringe filter; 2-5 L, then use a 50mm syringe filter. Sterile or nonsterile? Syringe filters are available in nonsterile and sterile options. Determining which option is best for your application is based on the type of environment in which you are performing the cell culture. Generally, sterile syringe filters are used if you need to sterilize or filter out cell culture reagents, such as biological solutions, cell culture media, serum, supplements, antibiotics, and viruses for infection. Still Have Questions? Get more information from our filtration guides and charts here. 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