Cell-culture broth flows left to right through three chromatography
stages. Capture (Protein A) binds the target antibody while
most host-cell protein and DNA flow to waste. Polish (ion
exchange) removes remaining trace impurities and aggregates.
Viral filtration is a final membrane barrier for virus
clearance. Purity climbs at every stage; yield only ever falls,
since some product is always lost with the impurities.
purity(n) = purity(n−1) + (100 − purity(n−1)) · removal_efficiency
yield(n) = yield(n−1) · step_recovery
- Flow rate — linear velocity through the resin bed; faster flow shortens residence time and reduces binding/removal efficiency at each column.
- Elution gradient — salt/pH ramp that releases bound product from the resin; too shallow leaves product on the column, too steep co-elutes impurities.
- Stage focus buttons — camera moves to inspect the resin bed detail of that unit operation.
- Feed preset — a high-titer feed starts with more contaminant particles, showing why more challenging feeds need more polishing capacity.