Unchained Labs eBook - 25

Unleash your biologic * Kick manual buffer exchange to the curb

accordingly. This helps ensure that protein quality is maintained
during the exchange, and allows the instrument to hit the final
concentration and volume target.
The two instrument formats are most valuable at different stages of
formulation studies. Junior, which uses a 96-well filter plate called
the Unfilter, is likely to fit best in an earlier construct selection phase,
when there are more samples at volumes under 500 µL. Junior
provides flexibility in buffer exchange settings, such as control over
the mixing speed, the pressure level and the maximum cycle
duration. The integrated volume check measurement provides an
additional feedback loop in the software. The software can address
scenarios where some wells exchange faster than others, and has
the flexibility to pool wells at the end of a run.
Grunt exchanges one protein in up to 12 formulations simultaneously.
Grunt uses Funls, which can exchange sample volumes up to 8 mL
per formulation, a scale which is appropriate for later stage preformulation screening or final formulation optimization. Grunt also
adds buffer preparation capabilities. Starting from liquid stock
buffers and stock excipients, it creates the desired formulation
buffer, including pH titrations and measurements. Grunt can
address buffer exchange at high protein concentrations, which
could take overnight or days to accomplish due to the more
viscous nature of these samples. Grunt provides temperature
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Figure 4.
Protein concentration in each formulation measured after
Junior buffer exchange.

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