Quantitative Flow Measurements in Bioreactors by Nuclear Magnetic Resonance Imaging

We have developed nuclear magnetic resonance (NMR) flow imaging techniques to measure fluid flow in a cell-free hollow fiber bioreactor (HFBR). Using 1 H NMR we track the motion of protons and obtain velocity distributions as a function of position and time. These measurements enable the visualization of flow patterns needed for module design and for establishing desired operating conditions. Uneven flow in the cell-containing region of an HFBR can result in concentration gradients and uneven cell distribution that may lead to reduced cell viability. Results from this non-invasive method could be used to design more efficient cell bioreac-tors or membrane separation devices.