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In vivo fluorescence imaging in the shortwave infrared (SWIR, 1,000–1,700 nm) and extended SWIR (ESWIR, 1,700–2,700 nm) regions has tremendous potential for diagnostic imaging. Although image contrast has been shown to improve as longer wavelengths are accessed, the design and synthesis of organic fluorophores that emit in these regions is challenging. Here we synthesize a series of silicon-RosIndolizine (SiRos) fluorophores that exhibit peak emission wavelengths from 1,300–1,700 nm and emission onsets of 1,800–2,200 nm. We characterize the fluorophores photophysically (both steady-state and time- resolved), electrochemically and computationally using time-dependent density functional theory. Using two of the fluorophores (SiRos1300 and SiRos1550), we formulate nanoemulsions and use them for general systemic circulatory SWIR fluorescence imaging of the cardiovascular system in mice. These studies resulted in high-resolution SWIR images with well-defined vasculature visible throughout the entire circulatory system. This SiRos scaffold establishes design principles for generating long-wavelength emitting SWIR and ESWIR fluorophores.
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Silicon incorporation in polymethine dyes
Methods to red-shift fluorophores have garnered considerable interest due to the broad utility of low energy light. The incorporation of silicon into xanthene and coumarin scaffolds has resulted in an array of visible and near-infrared fluorophores. Here, we extend this approach to polymethine dyes, another popular fluorophore class, performing experimental and computational analyses. We found that when oxygen was replaced with SiMe 2 , bathochromic shifts of up to 121 nm and fluorophores with emission above 900 nm were achieved.
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- Award ID(s):
- 1940307
- PAR ID:
- 10182783
- Date Published:
- Journal Name:
- Chemical Communications
- Volume:
- 56
- Issue:
- 45
- ISSN:
- 1359-7345
- Page Range / eLocation ID:
- 6110 to 6113
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/c9cc09671j
