Continuous In-line Monitoring of Perfusion Culture Viability with Contact-Free Magnetic Resonance Relaxometry

Motivation: Bioreactor cell density measurements currently require removing samples from the culture. This limits how many samples can be taken in a day and precludes real-time culture monitoring. Goal(s): We sought to take nondestructive cell density measurements every ten minutes without removing cells from the bioreactor. Approach: We built a system that takes T2 relaxometry measurements through the bioreactor’s silicone tubing every ten minutes and compared these to measurements taken by a commercial cytometry system. Results: The T2 relaxation data closely tracks the true cell density. Changes made to the culture are detected much more quickly by the relaxometer. Impact: Magnetic resonance relaxometry can be used to track bioreactor culture growth in real time, and makes it possible to identify and correct problems with the culture before the culture fails.