Multicomponent bioluminescence imaging in vivo requires an expanded collection of tissue-penetrant probes. Toward this end, we generated a new class of near-infrared (NIR) emitting coumarin luciferin analogues (CouLuc-3s). The scaffolds were easily accessed from commercially available dyes. Complementary mutant luciferases for the CouLuc-3 analogues were also identified. The brightest probes enabled sensitive imaging in vivo. The CouLuc-3 scaffolds are also orthogonal to popular bioluminescent reporters and can be used for multicomponent imaging applications. Collectively, this work showcases a new set of bioluminescent tools that can be readily implemented for multiplexed imaging in a variety of biological settings.
Alkyne-based Raman tags have proven
their utility for
biological
imaging. Although the alkynyl stretching mode is a relatively strong
Raman scatterer, the detection sensitivity of alkyne-tagged compounds
is ultimately limited by the magnitude of the probe’s Raman
response. In order to improve the performance of alkyne-based Raman
probes, we have designed several tags that benefit from π–π
conjugation as well as from additional n−π conjugation
with a sulfur linker. We show that the sulfur linker provides additional
enhancement and line width narrowing, offering a simple yet effective
strategy for improving alkyne-based Raman tags. We validate the utility
of various sulfur-linked alkyne tags for cellular imaging through
stimulated Raman scattering microscopy.
The cross-coupling of S-aryl and S-alkyl potassium thiomethyltrifluoroborates
with aryl and heteroaryl
bromides is reported via photoredox/nickel dual catalysis. The transformation
is achieved under mild conditions with commercially available or readily
prepared, air stable reagents and affords benzylthioether products
in moderate to good yields with good functional group tolerance. A
practical and improved synthesis of potassium thiomethyltrifluoroborates
is also reported that affords access to previously undescribed reagents.
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