Mitochondrial
Imaging with Combined Fluorescence and
Stimulated Raman Scattering Microscopy Using a Probe of the Aggregation-Induced
Emission Characteristic
posted on 2017-11-07, 00:00authored byXuesong Li, Meijuan Jiang, Jacky W. Y. Lam, Ben Zhong Tang, Jianan Y. Qu
In vivo quantitative
measurement of biodistribution
plays a critical role in the drug/probe development and diagnosis/treatment
process monitoring. In this work, we report a probe, named AIE-SRS-Mito,
for imaging mitochondria in live cells via fluorescence (FL) and stimulated
Raman scattering (SRS) imaging. The probe features an aggregation-induced
emission (AIE) characteristic and possesses an enhanced alkyne Raman
peak at 2223 cm–1. The dual-mode imaging of AIE-SRS-Mito
for selective mitochondrion-targeting was examined on a homemade FL–SRS
microscope system. The detection limit of the probe in the SRS imaging
was estimated to be 8.5 μM. Due to the linear concentration
dependence of SRS and inertness of the alkyne Raman signal to environmental
changes, the intracellular distribution of the probe was studied,
showing a local concentration of >2.0 mM in the mitochondria matrix,
which was >100-fold higher than the incubation concentration. To
the
best of our knowledge, this is the first time that the local concentration
of AIE molecules inside cells has been measured noninvasively and
directly. Also, the nonquenching effect of such AIE molecules in cell
imaging has been verified by the positive correlation of FL and SRS
signals. Our work will encourage the utilization of SRS microscopy
for quantitative characterization of FL probes or other nonfluorescent
compounds in living biological systems and the development of FL–SRS
dual-mode probes for specific biotargets.