Some methods allow in vivo measurements of cellular metabolism. Nuclear magnetic resonance (NMR) spectroscopy can monitor important phosphorus containing intracellular metabolites in vivo by 31P NMR but the overall sensitivity to cellular metabolites is relatively low. This limitation can be overcome only by a high concentration of cells, which needs to be homogenously distributed throughout the whole measurement period.
Consequently the cellular precipitation of the suspension must be prevented and at the same time all of the required nutrients must be distributed homogenously to avoid variations of metabolic changes during the NMR monitoring. In addition, a stirring device should not disturb the NMR magnetic field.
To meet this requirement, the recently developed device use gas bubbles for a constant stirring of an NMR tube.
The principle is shown in the figure for a conventional 8 mm NMR glass tube. Blue arrows represent the gas flow and red arrows show the movement of the cell suspension.
The rate of gas flow is adjustable and is sufficiently strong to result in stirring of the cell suspension across the whole volume of the NMR tube. It is important to notice, that no gas bubbles crossing the sensitive volume of the NMR instrument. The homogeneity of the magnetic field within the sensitive volume is not affected by the stirring process. The device is adaptable to different NMR tube sizes and instrument requirements.

IP Situation

The German patent DE102009013930B4 is granted.

Commercial opportunity

For manufacturers and distributors of NMR instruments and equipment.

Literature

M. Zakhartsev and C. Bock: “Miniaturized device for agitating a high-density yeast suspension that is suitable for in vivo nuclear magnetic resonance applications” Analytical Biochemistry 397 (2010), 244-246.