Buffer exchange & sample preparation

The problem

Buffer exchange and sample concentration is part of everyday life for scientists working with antibodies and recombinant proteins. Whether it’s for sample prep, preparing for labeling or characterization, or developing formulation screening and optimization strategies for a biologic, the process is monotonous, labor-intensive, time-consuming, and prone to error.

Conventional buffer exchange methods like dialysis and centrifugal filtration suffer from inconsistency in results and are often hard to manage in larger numbers. Sample concentration is usually an additional time-consuming step. Most methods require hands-on time, taking researchers away from other critical work.

The right tool for the job

Big Tuna is a fully automated buffer exchange system that provides a more uniform sample handling approach and degrees of process control that you just can’t get with manual methods. Big Tuna uses a modified ultrafiltration/diafiltration (UF/DF) method to exchange and concentrate proteins from 0.1 – 200 mg/mL. Big Tuna monitors the sample volumes during the run, adds back the filtered volume and gets your samples to the right percent exchange and concentration every time.


Big Tuna’s UF/DF method with gentle orbital mixing gives you consistent results without the drawbacks of dead-end ultrafiltration techniques. This matters because at high protein concentrations, the risk of aggregation goes up and proteins may gel at the membrane. Orbital mixing helps the sample flow faster and reduces the potential for aggregation.


Big Tuna uses a plate-based consumable called the Unfilter. All Unfilters use a regenerated cellulose membrane which is ideal for proteins because it minimizes non-specific binding. They come in 2 formats, 24-well (0.45 – 8 mL) or 96-well (100 – 450 µL). The Unfilter 96 is available with molecular weight cutoffs of 3, 10, 30, and 100 kDa. The Unfilter 24 has 10, 30, and 100 kDa MWCOs. So no matter what size the protein is or what volume is available, Big Tuna has the right format.


The proof

Fast formulation screening and optimization

Screening for the optimal pH for your antibody is easier than ever before. It only takes 30 minutes to set up and you’ll be running your stability measurements in no time.

formulation screening and optimization
Dialing in your formulation

Finding the right excipients to keep your proteins happy is a challenge. Big Tuna can help you with this too. At this stage of formulation development these samples aren’t likely to run uniformly. Big Tuna has you covered by constantly monitoring the volume and flow rate so it can exchange the slowpokes without letting the speedster wells go dry. If you want to concentrate them up to dosable levels at the end, Big Tuna can do that too.

Dialing in your formulation
Big Tuna front_crop

Big Tuna

Buffer exchange and sample concentration are the time consuming, hands-on chores you have to deal with before all the things you really want to do. Big Tuna automates exchange to formulate, concentrate and clean up proteins or gene therapy vectors like AAVs, LNPs, and VLPs — with just 30 mins of setup time. Skip the slow and manual ways of prepping samples to free yourself up for other critical work.

Want more info?

Want to learn more about how Big Tuna frees you up from buffer exchange?