Local Stiffness\nMeasurement of Hepatic Steatosis Model\nLiver Organoid by Fluorescence Imaging-Assisted Probe Indentation

Mechanical\nstiffness of liver organoid is a key indicator for the\nprogress of hepatic steatosis. Probe indentation is a noninvasive\nmethodology to measure Young’s modulus (YM); however, the inhomogeneous\nnature of the liver organoid induces measurement uncertainty requiring\na large number of indentations covering a wide scanning area. Here,\nwe demonstrate that lipid-stained fluorescence imaging-assisted probe\nindentation significantly reduces the number of measurements by specifying\nthe highly lipid-induced area. Lipid-stained hepatic steatosis model\nliver organoid shows broad fluorescence distributions that are spatially\ncorrelated with a decreased YM on a lipid-filled region with bright\nfluorescence compared with that measured on a blank region with dark\nfluorescence. The organoid viability remained robust even after exposure\nto an ambient condition up to 6 h, showing that probe indentations\ncan be noninvasive methods for liver organoid stiffness measurements.