Extended Data Fig. 3: Establishment of an Integrated 2-PMT Heart-on-a-chip platform.
From: Electro-metabolic coupling in multi-chambered vascularized human cardiac organoids
a, Scheme and typical measurements depicting the advantages of using a 2-PMT system over a single PMT system. The addition of the second detector (cPMT), which measures the excitation signal, reduces the noise and enables accurate measurements at sub-second resolution. The second PMT also allows an emission-independent measurement of tissue contraction (methods). b, Representative calibration measurements of the reflected signal measured by the second PMT in different displacements. Curve fitting displays a sigmoidal relationship between the emission intensity, measured by peak-to-peak voltage (VP-P), and the sensor displacement. Cardiac displacement was measured by the embedded oxygen beads inside the cardiac organoids during a contraction when the beads move at different distances from the focal point. The Sigmoidal fit shows a correlation of R-square: 0.9835 and RMSE below 4. c, Representative continuous interstitial oxygen measurements in cardiac organoids measured continuously over 10 hours. Measurements show steady recordings that are unaffected by photobleaching or system sensitivity loss at prolonged measurements. Oxygen content and oscillation were unchanged even after 10 hours of measurement.
