Bioprocessing Fundamentals

The engineering behind single-use bioprocessing.

Pump science. Valve engineering. TFF science. Written by the engineers who build the equipment, for the engineers who specify and run it. Three disciplines that determine whether a single-use system performs the way the molecule needs it to.

3
Engineering disciplines
20+
Technical articles
May 2026
Last reviewed

The disciplines

Three engineering disciplines. One bioprocess.

Each discipline has its own depth, its own variables, and its own consequences for the modalities Alphinity serves. Pick a starting point.

Pump Science

How a pump moves fluid, and what it does to the molecule on the way through.

Positive displacement, peristaltic, and centrifugal designs. Shear, cavitation, pulsation, viscosity, and scale-up. The discipline behind why two pumps rated for the same flow rate can do very different things to your product.

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Valve Engineering

How a valve controls flow and keeps a process closed.

Diaphragm, pinch, and check designs, across single-use and stainless multi-use. Hold-up volume, dead leg, actuation, and closure dynamics. The discipline behind clean, closed, controlled transitions between unit operations.

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TFF Science

How a TFF system concentrates the molecule without compromising it.

Transmembrane pressure, concentration polarization, flux decline, gel layer dynamics, and skid architecture. The discipline behind concentration and diafiltration that protects the molecule, not just retains it.

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Common questions

Fundamentals, briefly.

One-paragraph answers for readers arriving from a search query. The full explanation lives on each discipline's pillar page.

What is the difference between peristaltic and positive displacement pumping?

A peristaltic pump moves fluid by compressing flexible tubing against a rotor; a positive displacement diaphragm pump moves fluid by displacing a fixed volume in a chamber on each cycle. The two architectures produce very different shear profiles, pulsation behavior, and stability at low flow rates. Read pump science.

What does hold-up volume mean and why does it matter?

Hold-up volume is the fluid retained inside a valve, fitting, or assembly after it is supposed to be empty. In small-batch and autologous workflows, hold-up volume is product loss. The valve architecture and the geometry of the flow path determine how much is lost on every transition. Read valve engineering.

Why does transmembrane pressure stability matter in TFF?

TMP determines flux through the membrane and the formation of the concentration polarization layer. When pulsation or pump instability creates noise in the TMP signal, the control loop oscillates, flux becomes inconsistent, and membrane fouling accelerates. Holding TMP steady is the operational variable that everything downstream depends on. Read TFF science.

How do these three disciplines work together in a single-use process?

A bioprocess is a chain of unit operations. Pumps deliver flow, valves direct it and isolate sections of the train, TFF skids concentrate and diafilter. A failure in any one of the three propagates downstream. Equipment selection is a system question, not a component question. Talk to engineering.

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