Broadband Electrical Spectroscopy to Distinguish Single-Cell Ca Changes Due to Ionomycin Treatment in a Skeletal Muscle Cell Line.

Many skeletal muscle diseases such as muscular dystrophy, myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and sarcopenia share the dysregulation of calcium (Ca) as a key mechanism of disease at a cellular level. Cytosolic concentrations of Ca can signal dysregulation in organelles including the mitochondria, nucleus, and sarcoplasmic reticulum in skeletal muscle. In this work, a treatment is applied to mimic the Ca increase associated with these atrophy-related disease states, and broadband impedance measurements are taken for single cells with and without this treatment using a microfluidic device. The resulting impedance measurements are fitted using a single-shell circuit simulation to show calculated electrical dielectric property contributions based on these Ca changes. From this, similar distributions were seen in the Ca from fluorescence measurements and the distribution of the S-parameter at a single frequency, identifying Ca as the main contributor to the electrical differences being identified. Extracted dielectric parameters also showed different distribution patterns between the untreated and ionomycin-treated groups; however, the overall electrical parameters suggest the impact of Ca-induced changes at a wider range of frequencies.