Rhythmic potassium transport regulates the circadian clock in human red blood cells.

Circadian rhythms organize many aspects of cell biology and physiology to a daily temporal program that depends on clock gene expression cycles in most mammalian cell types. However, circadian rhythms are also observed in isolated mammalian red blood cells (RBCs), which lack nuclei, suggesting the existence of post-translational cellular clock mechanisms in these cells. Here we show using electrophysiological and pharmacological approaches that human RBCs display circadian regulation of membrane conductance and cytoplasmic conductivity that depends on the cycling of cytoplasmic K+ levels. Using pharmacological intervention and ion replacement, we show that inhibition of K+ transport abolishes RBC electrophysiological rhythms. Our results suggest that in the absence of conventional transcription cycles, RBCs maintain a circadian rhythm in membrane electrophysiology through dynamic regulation of K+ transport

Biophysical Characteristics Reveal Neural Stem Cell Differentiation Potential

Distinguishing human neural stem/progenitor cell (huNSPC) populations that will predominantly generate neurons from those that produce glia is currently hampered by a lack of sufficient cell type-specific surface markers predictive of fate potential. This limits investigation of lineage-biased progenitors and their potential use as therapeutic agents. A live-cell biophysical and label-free measure of fate potential would solve this problem by obviating the need for specific cell surface markers

Dielectrophoresis as a cell characterisation tool.

Dielectrophoresis (DEP) is a technique which offers label-free measurement of cell electrophysiology by monitoring its movement in non-uniform electric fields. In this chapter, the theory underlying DEP is explored, as are the implications of the development of equipment for taking such measurements. Practical considerations such as the selection of a suspending medium are also discussed

Dielectrophoresis as a cell characterisation tool.

Dielectrophoresis (DEP) is a technique which offers label-free measurement of cell electrophysiology by monitoring its movement in non-uniform electric fields. In this chapter, the theory underlying DEP is explored, as are the implications of the development of equipment for taking such measurements. Practical considerations such as the selection of a suspending medium are also discussed