Real-time monitoring of Ca2+ concentration in pancreatic beta cells by a microfluidic device integrated with Total Internal Reflection (TIR)-based chip

We present a microfluidic device integrated with a Total Internal Reflection (TIR)-based chip for cell observation and analysis, which enables Total Internal Reflection Fluorescence Microscopy (TIRFM). By integrating the microfluidic device with optical components, the assembly becomes unnecessary. An evanescent field generated by the TIR-based chip was demonstrated by observation of fluorescent beads and insulin granules in mouse pancreatic beta cells, MIN6-m9. Comparing with epi-fluorescence microscopy (EPIFM), high S/N ratio of 4-fold was realized by the TIR-based chip. To demonstrate the utility of the device integration, we analyzed intracellular Ca²⁺ concentration change in MIN6-m9 cells in response to KCl stimulation. We found out our integrated device realized quick perfusion for cell analysis with keeping high S/N ratio.