Cell apoptosis detection based on the functionality changes of cellular organelles, such as mitochondria, offers a quantitative method compared to morphology-based detection. However, the conventional detection methods for potential variation of the mitochondrial membrane based on fluorescence spectrum changes cannot offer a precise quantification of the degree of apoptosis. Here, a mitochondria-targeted two-photon viscosity probe (TPA-Mit), which sensitively responds to viscosity variations with fluorescence lifetime changes, is designed to detect the viscosity of mitochondria. Noteworthily, the proposed phasor fluorescence lifetime imaging microscopy (phasor-FLIM) allows for more precise quantification (in terms of smaller uncertainty) when estimating the degree of apoptosis with a microviscosity probe. The experimental results of SKOV-3 cells show that the fluorescence lifetime of mitochondria-targeted TPA-Mit increased from 550 ps to 800 ps after 24 hours of paclitaxel (PTX)-induced apoptosis. We believe that our method provides a new means for the measurement of cellular microviscosity and apoptosis monitoring at early stages.
Keyphrases
- fluorescent probe
- living cells
- induced apoptosis
- endoplasmic reticulum stress
- cell cycle arrest
- cell death
- single molecule
- oxidative stress
- high resolution
- label free
- energy transfer
- reactive oxygen species
- endoplasmic reticulum
- pi k akt
- cancer therapy
- signaling pathway
- real time pcr
- loop mediated isothermal amplification
- quantum dots
- cell proliferation
- high speed
- sensitive detection