The effect of ionic redistributions on the microwave dielectric response of cytosol water upon glucose uptake

Abstract

The sensitivity of cytosol water's microwave dielectric (MD) response to D-glucose uptake in Red Blood Cells (RBCs) allows the detailed study of cellular mechanisms as a function of controlled exposures to glucose and other related analytes like electrolytes. However, the underlying mechanism behind the sensitivity to glucose exposure remains a topic of debate. In this research, we utilize MDS within the frequency range of 0.5-40 GHz to explore how ionic redistributions within the cell impact the microwave dielectric characteristics associated with D-glucose uptake in RBC suspensions. Specifically, we compare glucose uptake in RBCs exposed to the physiological concentration of Ca²⁺ vs. Ca-free conditions. We also investigate the potential involvement of Na⁺/K⁺ redistribution in glucose-mediated dielectric response by studying RBCs treated with a specific Na⁺/K⁺ pump inhibitor, ouabain. We present some insights into the MD response of cytosol water when exposed to Ca²⁺ in the absence of D-glucose. The findings from this study confirm that ion-induced alterations in bound/bulk water balance do not affect the MD response of cytosol water during glucose uptake.

Keywords: Cytosol water; Glucose uptake; Microwave dielectric spectroscopy; Non-invasive glucose monitoring; Red blood cells; Water.