Dielectric Properties of Cells Under Simulated Microgravity Conditions

Introduction

Human activities beyond Earth have steadily increased. During spaceflight, NASA observed that the lack of Earth's gravity causes a 1-1.5% monthly loss in the mineral density of weight-bearing bones. Even after returning, rehabilitation may be ineffective. The effects extend to muscles, the neuro-vestibular system, heart, eyes, and more. Understanding microgravity's effects on the human body is critical; however, sending samples to space is costly and time-consuming. Thus, technologies like the clinostat can simulate microgravity on Earth.

Methods

RBCs from cancer patients are used to investigate the impacts of microgravity. The link between microgravity-induced metabolic changes in their morphology and cytoplasm properties is poorly understood. To explore these changes, we will expose the RBCs to microgravity using a 3D clinostat, and using dielectrophoresis, an electrokinetic technique, we will analyze the dielectric profile related to morphological and cytoplasmic changes. The cells are suspended in media (8.6wt% sucrose + 0.3wt% dextrose in 100ml DI water), transferred into 1.5-ml centrifuge tubes, and exposed to microgravity for 1-24 hours at a specific conductivity (0.01 S/m), adjusted with 1xPBS.

Results

Cell behavior is quantified using the DEP crossover technique (when no DEP force occurs), where cells neither migrate toward nor away from the high electric field region at a specific AC frequency and peak-to-peak voltage. The results show statistically significant variations in membrane permittivity and conductivity between Earth and microgravity conditions. The folding factor of microgravity-induced cells decreased drastically. A decrease in the folding factor suggests altered cell structure and function, potentially affecting protein folding, morphology, and cellular processes.

Conclusions

These results help understand the effect of microgravity on changes in the morphology and cytoplasm of RBCs. The goal of this research is to enhance the understanding of the impacts of microgravity on the human body and advance space health studies.