PROTEIN CONCENTRATION & BUFFER EXCHANGE

Biomolecule purification involves a complex series of steps where targets are selectively separated through sequential processes. The process by which separation is performed often creates a need for the sample to be desalted or concentrated to prepare the biomolecule sample for the next step in the purification process. We offer several technologies to perform efficient sample concentration, desalting, and buffer exchange including ultrafiltration (UF) spin filters, UF multi-well filtration plates.

Ultrafiltration involves forcing a protein solution through a membrane with a defined molecular weight cutoff. The protein does not pass through the membrane, whereas the other buffer components do. This method is usually relatively rapid and does not adversely affect the protein sample. Ultrafiltration is carried out by centrifugation. The protein sample is placed into the cartridge and spun until the protein solution, which remains above the filter, is at the desired volume. The filtrate can also be recovered and evaluated. 

One of the other common applications for these devices is buffer exchange or desalting.  There are some very salt sensitive downstream applications out there, such as gel electrophoresis, NMR, X-Ray crystallography, and mass spectrometry. Salt needs to be removed before conducting these applications. One simple way to achieve this is to use a centrifugal device, such as the Nanosep® and Nanosep MF Centrifugal Devices.

Our Ultrafiltration (UF) centrifugal devices facilitate pure product with > 90% recoveries in just minutes. Ultrafiltration is a membrane separation technique based on selection by molecular size, although other factors, such as molecule shape and charge, can also play a role. Molecules larger than the membrane pores in the UF membrane will be retained at the surface of the membrane while solvent and smaller solute molecules will freely pass. This molecular exclusion at the UF membrane surface leads to concentration of the protein solute in the retained fraction (termed the retentate) and can be recovered from above the membrane.

We offer a complete range of ultrafiltration devices suitable for various sample volumes. These centrifugal devices are specifically engineered to provide faster flow rates and easier handling. Devices are available with low protein binding Omega ultrafiltraion membrane.