Polyethersulfone (PES) FAQ

Polyethersulfone (PES) membrane filters offer very low protein binding, high flow rates, and excellent throughput, making them ideal for sterile filtration of cell culture media, buffers, biological fluids, and other life science applications. PES membranes also provide broad chemical compatibility and reliable performance, making them a preferred choice for microbiology, biopharmaceutical processing, and routine laboratory filtration.

Polyethersulfone (PES) membrane filters have an asymmetric pore structure, with larger pores on one side and smaller pores on the other. The larger-pore side has a dull or matte appearance, while the smaller-pore side appears smoother and shinier. For maximum flow rate and filtration throughput, install the membrane with the dull/matte (larger-pore) side facing upstream. For microscopy or particle capture applications, orient the shiny (smaller-pore) side upstream to retain particles closer to the membrane surface, although this may reduce flow rate and throughput.

Polyethersulfone (PES) membrane filters are asymmetric, with larger pores on one side and smaller pores on the opposite side. The larger-pore side appears dull or matte, while the smaller-pore side appears smoother and shinier when viewed under reflected light. The membrane can be installed in either orientation without affecting particle retention. However, for optimal performance: Dull/matte side upstream: Maximizes flow rate and filtration throughput. Shiny side upstream: Improves surface particle capture for microscopy and particle analysis, with some reduction in throughput.

Generally, no. Polyethersulfone (PES) membrane filters have low protein-binding capacity, making them unsuitable for most lateral flow assays, which require membranes with high protein binding to effectively immobilize antibodies and other biomolecules.

Sterlitech does not provide a membrane-specific validated ethylene oxide (EtO) sterilization protocol for 0.2 µm PES (polyethersulfone) membrane filters. However, these filters are generally compatible with standard EtO sterilization processes.