Dielectrophoretic Based Molecular Targeting for Blood Chronobiology

The current model of the regulation of the body’s circadian rhythm (the 24 hour internal body clock) relies on the rhythmic expressions of ‘clock genes’ over a 24 hour cycle. These rhythms are of importance and general interest as they are observed in most mammalian cells, in vivo and in vitro, whilst disruption of these rhythms has been linked to many significant diseases. Work published in 2011 demonstrated, for the first time, rhythmicity in red blood cells (RBCs). Mature RBCs shed their nucleus to maximize their accommodation of haemoglobin and thus are anucleated. Since RBCs contain no nucleus, they are incapable of transcription and thus a cycling gene clock cannot exist in these cells. Very little is known about RBC clock mechanisms, or whether functional consequences exist for erythrocyte biology.

To address this question we have employed the dielectrophoretic-based platform, 3DEP, to characterize isolated RBCs (in vitro) as well as whole blood samples (in vivo) taken from human and animal subjects. A myriad of experiments has shown robust rhythmicity of the resistive properties (specifically, membrane conductance and cytoplasmic conductivity) of RBCs in vivo and in vitro. Pharmacological interventions have suggested that this mechanism is at least partially electrophysiologically driven. This work continues in delineating this mechanism through further modifications of the cells in vitro.

Additionally, methods have been optimized for the in vivo investigation into animal models. This is a significant contribution to the field in not only supporting the in vitro work, but since the assay is non-terminal, could greatly reduce animal use in these studies. These assays also serve to give a better understanding into the nature of the rhythms present in whole blood.