Sterile Filtration

Tested, trusted products for your lab’s sterilization and clarification needs

When applying sterile filtration techniques in your lab, we understand that the products you use are critical to reducing contamination and ensuring that important media components aren’t removed during the process. That’s why our Thermo Scientific Nalgene Rapid Flow filters are trusted by labs globally to help support their sterilization and clarification needs. 

Nalgene Rapid Flow filter units and bottle tops

Nalgene Rapid Flow Filter Units and Bottle Tops provide superior flow rates, and help reduce downtime for cell culture applications. Choosing whether to use a bottle top or filter unit almost always depends on how long you plan on storing your solutions.

Filter unit


  • Best for storing your solution for less than two weeks
  • Easily removable upper unit filter membrane provides the best choice for temporary storage purposes
Bottle Top


  • Best for storing your solutions for longer than two weeks
  • Sterilized glass bottles help improve the storage time without pH shift to maintain sample integrity

Choosing the right pore size

For sterilizing filtration, it’s imperative that you always use a 0.2µm pore size membrane filter, regardless of the filter material. Other commonly used pore sizes include: 

0.65/0.8μm 0.45μm 0.2μm 0.1μm
Analysis of mold, fungi and yeast, stabilization of fermented product, clarification and prefiltration Analysis of bacteria, sterility testing, clarification and prefiltration

Sterilization, sterility testing, “final filtration”


Reduction of mycoplasma, ultracleaning

Tested, trusted rapid flow

Rapid Flow filters are designed with a unique membrane support plate that’s welded into its housing to help ensure membrane fluid path integrity. Combined with the correct Rapid Flow membrane, the results are superior flow rates with minimal pressure drop, which leads to particle specifications in less time and drastically increased productivity.

Featured video

View the difference and importance of the Nalgene Rapid Flow advantage:

  • Membrane stability
  • Consistent performance
  • Faster flow
  • More throughput


Select a membrane


Asymmetric PES (aPES) membranes are highly retentive asymmetric PES filters designed to meet the exacting requirements of cell culture media and sera applications. 


Surfactant-free cellulose acetate (SFCA) membranes are very low protein and nucleic acid binding and have lower extractables than standard CA membranes.  Nylon membranes are higher protein binding and should be used when very low extractables are desired with solutions containing weak solvents, such as alcohols. Cellulose nitrate (CN) membrane is excellent for clarification of buffers, water and salt solutions when protein binding is not a concern. Glass fiber prefilter discs are used in conjunction with Nalgene filter units or bottle top filters to increase filtration speed and throughput of highly viscous or heavily particulated solutions. Designed to capture larger size particles for general purpose prefiltration applications. 
Fast & very low binding Low protein binding (not very low) Great for HPLC samples   Solutions with heavy particle loads