Flipper-TR® Membrane Tension Probes for Lysosomes, Mitochondria, and Endoplasmic Reticulum

Spirochrome’s fluorescent lipid tension reporter (Flipper TR™) probes are now available as organelle-specific dyes to interrogate cellular organelles1. The new fluorogenic targeted-Flippers utilize the original breakthrough Flipper-TR™ mechanophore, but integrate organelle-specific motifs to enable investigators to measure membrane tension in lysosomes, mitochondria, and endoplasmic reticulum (ER) (Figure 1). Lyso Flipper-TR™ (Cat. # CY-SC022), Mito Flipper-TR™ (Cat. # CY-SC023), ER Flipper-TR™ (Cat. # CY-SC021), and Flipper-TR™ (Cat. # CY-SC020) are compatible with co-labeling experiments and all four probes are excited at the 488 nm wavelength with emission between 575 nm and 625 nm wavelengths. More information about the targeted Flipper-TR™ probes can be seen in the ACS publication.


Figure 1. A) FLIM images of HeLa cells labeled with Lyso Flipper-TR™ before and after osmotic shock. B) FLIM image of HeLa cells labeled with Mito Flipper-TR™ with profile showing lifetime & intensity vs. distance during mitochondrial constriction. C) FLIM and intensity images of a HeLa cell labeled with ER Flipper-TR™.

Flipper TR™’s mechanophore enables probes to exhibit two distinct fluorescence lifetimes depending upon their structural status giving investigators the ability to interrogate membrane tension with microscopy2 (Figure 2). Flipper TR™ probes integrated within a low-tension cell membrane assume semi-planarized states exhibiting relatively short fluorescence lifetimes. Conversely, when membrane tensions are high, membrane phospholipid pressures force Flipper TR™ probes to convert into planarized conformations, resulting in substantial increases in fluorescence lifetimes that can be quantitated and visualized using FLIM microscopy. Read more about the original Flipper-TR™ probe here and in the breakthrough publication.


Figure 2. Flipper-TR staining of cells. Left side: Image of cells stained with Flipper-TR®  before (top) and after (bottom) hyperosmotic shock. Greyscale represents fluorescence intensity, and color codes represent fluorescence lifetime. On the right the histogram shows the lifetime shift after osmotic shock. Images courtesy of Colom et al. 2018(1). Flipper-TR is a registered trademark of UNIGEM, Switzerland.

Interrogate plasma membrane tension with mechanosensing Flipper probes.

Flipper-TR Probes

Excitation (nm)
Emission (nm)
Lyso Flipper-TR™ (Cat. # CY-SC022)488575-625
Mito Flipper-TR™ (Cat. # CY-SC023)488575-625
ER Flipper-TR™ (Cat. # CY-SC021)488575-625
Flipper-TR™ (Cat. # CY-SC020)488575-625


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  1. Goujon, A. et al. Mechanosensitive Fluorescent Probes to Image Membrane Tension in Mitochondria, Endoplasmic Reticulum, and Lysosomes. J. Am. Chem. Soc. 141, 3380–3384 (2019).
  2. Colom, A. et al. A fluorescent membrane tension probe. Nat. Chem. 10, 1118–1125 (2018).