Visualization 1

Dense interference fringes of primary ventricular cardiomyocytes grown on blank silicon surfaces. Sequences of interference fringes were recorded at 169 fps over an area of 57.0 mm2 and the periodic contractions of cardiac cells resulted in oscillations in pixel intensity

Visualization 3

Simultaneous electrophysiological and contractile monitoring through a combined CMOS-based microelectrode array (MEA) and reflective lens-free imaging (RLFI) setup. Interference patterns were recorded by RLFI over the full MEA surface (15.7mm2) and further processed. Intracellular-like action potential (AP) of single cells were synchronized with the relative cellular deformation (RCD) of a cluster of cells located in a region around the electrode of interest (white square, 0.3 mm2). Video recordings are shown at 0.5x actual frame rate

Visualization 4D 1000um

Detection of conduction disturbances in excitation wave propagation by increased concentration of 1-octanol (A: 0 μM; B: 1 μM; 10 μM and 100 μM not shown; C: 400 μM; and D: 1 mM; 0.1x actual velocity; scale bar: 2 mm). To visualize the flow of the excitation wave, sequences of interference fringes obtained by RLFI were processed to obtain relative pixel intensity variations. Briefly, pixel intensity variations were smoothened and locally normalized over regions of 0.05 mm2. (A) The propagation of the excitation wave over the cellular monolayer was recorded in cardiac medium and (1) cells were initially relaxed. (II) Contraction is initially detected in the left side of the monolayer and (III) the excitation wave propagated to the right over the monolayer leading to over a large area of the monolayer. Then, (IV) contraction is detected over the full monolayer until (V) the cells started relaxing. (VI) Cells were again fully relaxed between contractions. From RCD analysis, an excitation propagation velocity (EPV) of 238 ± 8 mm/s and a constant directionality were detected (white arrow). (B) The directionality of the excitation wave remained unchanged if cardiac cells were incubated at a low concentration of 1 μM, while the EPV reduced to 219 ± 16 mm/s. (C) EPV reduced to 83.8 ± 1.7 mm/s if cells were incubated at a concentration of 400 μM, while the direction of the excitation wave remained similar. (D) Prominent conduction disturbances became apparent at a concentration of 1 mM. The excitation wave broke off into multiple slower branches (white arrows in panels II, III, and IV), while the EPV of the main branch slowed down to 14 ± 2 mm/s

Visualization 4A 0um

Detection of conduction disturbances in excitation wave propagation by increased concentration of 1-octanol (A: 0 μM; B: 1 μM; 10 μM and 100 μM not shown; C: 400 μM; and D: 1 mM; 0.1x actual velocity; scale bar: 2 mm). To visualize the flow of the excitation wave, sequences of interference fringes obtained by RLFI were processed to obtain relative pixel intensity variations. Briefly, pixel intensity variations were smoothened and locally normalized over regions of 0.05 mm2. (A) The propagation of the excitation wave over the cellular monolayer was recorded in cardiac medium and (1) cells were initially relaxed. (II) Contraction is initially detected in the left side of the monolayer and (III) the excitation wave propagated to the right over the monolayer leading to over a large area of the monolayer. Then, (IV) contraction is detected over the full monolayer until (V) the cells started relaxing. (VI) Cells were again fully relaxed between contractions. From RCD analysis, an excitation propagation velocity (EPV) of 238 ± 8 mm/s and a constant directionality were detected (white arrow). (B) The directionality of the excitation wave remained unchanged if cardiac cells were incubated at a low concentration of 1 μM, while the EPV reduced to 219 ± 16 mm/s. (C) EPV reduced to 83.8 ± 1.7 mm/s if cells were incubated at a concentration of 400 μM, while the direction of the excitation wave remained similar. (D) Prominent conduction disturbances became apparent at a concentration of 1 mM. The excitation wave broke off into multiple slower branches (white arrows in panels II, III, and IV), while the EPV of the main branch slowed down to 14 ± 2 mm/s

Visualization 4C 400um

Detection of conduction disturbances in excitation wave propagation by increased concentration of 1-octanol (A: 0 μM; B: 1 μM; 10 μM and 100 μM not shown; C: 400 μM; and D: 1 mM; 0.1x actual velocity; scale bar: 2 mm). To visualize the flow of the excitation wave, sequences of interference fringes obtained by RLFI were processed to obtain relative pixel intensity variations. Briefly, pixel intensity variations were smoothened and locally normalized over regions of 0.05 mm2. (A) The propagation of the excitation wave over the cellular monolayer was recorded in cardiac medium and (1) cells were initially relaxed. (II) Contraction is initially detected in the left side of the monolayer and (III) the excitation wave propagated to the right over the monolayer leading to over a large area of the monolayer. Then, (IV) contraction is detected over the full monolayer until (V) the cells started relaxing. (VI) Cells were again fully relaxed between contractions. From RCD analysis, an excitation propagation velocity (EPV) of 238 ± 8 mm/s and a constant directionality were detected (white arrow). (B) The directionality of the excitation wave remained unchanged if cardiac cells were incubated at a low concentration of 1 μM, while the EPV reduced to 219 ± 16 mm/s. (C) EPV reduced to 83.8 ± 1.7 mm/s if cells were incubated at a concentration of 400 μM, while the direction of the excitation wave remained similar. (D) Prominent conduction disturbances became apparent at a concentration of 1 mM. The excitation wave broke off into multiple slower branches (white arrows in panels II, III, and IV), while the EPV of the main branch slowed down to 14 ± 2 mm/s

Visualization 2

Simultaneous monitoring of cardiac contraction through calcium imaging (green box, 0.11 mm2) and reflective lens-free imaging (RLFI, grayscale box, 0.3 mm2) in a combined RLFI-fluorescence microscope setup. The full sequences of images were processed to obtain the relative intracellular calcium concentration ([Ca2+]I,, green trace) and relative cellular deformation (RCD, blue trace). Higher [Ca2+]i and RCD values were obtained during contraction compared to in between beats