Cells and organelles are delimited by lipid bilayers in which high deformability is essential to many cell processes, including motility, endocytosis and cell division. Membrane tension is therefore a major regulator of the cell processes that remodel membranes, albeit one that is very hard to measure in vivo. Here we show that a planarizable push–pull fluorescent probe called FliptR (fluorescent lipid tension reporter) can monitor changes in membrane tension by changing its fluorescence lifetime as a function of the twist between its fluorescent groups. The fluorescence lifetime depends linearly on membrane tension within cells, enabling an easy quantification of membrane tension by fluorescence lifetime imaging microscopy. We further show, using model membranes, that this linear dependency between lifetime of the probe and membrane tension relies on a membrane-tension-dependent lipid phase separation. We also provide calibration curves that enable accurate measurement of membrane tension using fluorescence lifetime imaging microscopy.

细胞和细胞器由脂质双层界定，其中高变形性对于许多细胞过程（包括运动、内吞作用和细胞分裂）至关重要。因此，膜张力是重塑膜的细胞过程的主要调节因子，尽管在体内很难测量。在这里，我们展示了一种称为 FliptR（荧光脂质张力报告基因）的可平面推拉荧光探针，可以通过改变其荧光寿命作为其荧光基团之间扭曲的函数来监测膜​​张力的变化。荧光寿命线性取决于细胞内的膜张力，从而可以通过荧光寿命成像显微镜轻松量化膜张力。我们进一步表明，使用模型膜，探针寿命和膜张力之间的这种线性依赖性依赖于膜张力依赖性脂质相分离。我们还提供校准曲线，可以使用荧光寿命成像显微镜精确测量膜张力。