Cell calcium changes in response to endogenous and exogenous small molecules: Microfluidic single-cell monitoring and microplate bulk-cell measurement

Intracellular calcium ion ([Ca2+]i) is a messenger that regulates many cellular functions, and contributes to many biochemical cell processes. The measurement of calcium allows us to examine the responses of the cells to endogenous molecules (e.g. histamine) and exogenous molecules (e.g. cannabinoids). Measurement of [Ca2+]i can be done on a microfluidic chip or a microplate reader by monitoring the emitted fluorescence from the calcium-Fluo4 chelate formed inside the cell. While the calcium measurement is conducted on a single cell captured within a microchip chip, the microplate experiment is performed in a 96-well plate and each well contains around 40,000 cells and provides an average value for the cell response. The high number of cells in a microplate will allow researchers to perform bulk calcium analysis. On the other hand, the single-cell method by a microfluidic glass chip has advantages such as small reagent consumption and fast analysis. The combination of microfluidic single-cell and bulk-cell analysis of calcium will reveal detailed information about calcium concentration in two different scales. This allows us to examine the difference in cell responses obtained from two types of lung cancer cells, namely A549 cells and ACE2-enriched A549 cells.