Fig. 8
From: Mechanodynamic brain on chip for studying human stem cell derived neuronal networks
Calcium imaging and analyses workflow. (a) Schematic of the experimental strategy for culturing and imaging human induced pluripotent stem cell hiPSC-derived neurons. (b) Time-series images of 2D neuronal cell cultures showing \(\text {Ca}^{2+}\) waves at different time points, extracted from video recordings. The dashed lines indicate the underlying microchannel location. White arrows mark neurons undergoing \(\text {Ca}^{2+}\) flux, indicated by changes in fluorescence intensity under mechanical stimulation. A full movie is accessible via the QR code. (c) \(\text {Ca}^{2+}\) imaging of 2D cultured neuronal cells (DIV 21) loaded with a \(\text {Ca}^{2+}\) indicator. Dashed lines indicate the microchannel position underneath. White circles highlight regions of interest (ROIs) where fluorescence intensity was monitored. (d) \(\text {Ca}^{2+}\) activity profiles of selected cells, corresponding to the ROIs in (c). The red dashed line marks the time point when the stimulus was introduced. (e) Time-series images of a 3D neuronal network (cells extending in 3D via a gel layer), activated by chip stimulation. Images are extracted from video recordings of the observed \(\text {Ca}^{2+}\) wave at different time points. White arrows and dashed lines indicate the underneath microchannel, white arrows displaying neuronal cell firing that were undergoing a \(\text {Ca}^{2+}\) flux, revealed by the change of the fluorescence intensity under mechanical stimulation. The full movie is accessible via the QR code. (f) \(\text {Ca}^{2+}\) imaging of 3D-like neuronal cells, with ROIs marked by white circles. (g) \(\text {Ca}^{2+}\) activity profiles of selected cells, corresponding to the ROIs in (f). The red dashed line marks the time point when the stimulus was introduced. Scale bars: 75 \(\upmu\)m.
