Journal Article

Silicon-RosIndolizine fluorophores with shortwave infrared absorption and emission profiles enable in vivo fluorescence imaging

Shaik, Abdul K., Delcamp, Jared H., Caram, Justin R., Lin, Eric Y., Friedman, Hannah C., Meador, William E., Hammer, Nathan I., Lim, Irene, Yang, Boqian, Ndaleh, David, Sletten, Ellen M.

2024

Overview

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. Accessing longer-wavelength emitting organic fluorophores is critical for diagnostic imaging. Here a series of silicon-RosIndolizine fluorophores with emission maxima at 1,300 nm, 1,550 nm and 1,700 nm were synthesized. The fluorophores generate high-resolution in vivo fluorescence images in mice and establish design principles for future shortwave-infrared fluorophore designs.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 639/638/298/398 / 639/638/440/527/1819 / 639/638/440/527/1989 / 639/925/930/2735 / Analytical Chemistry / Animals / Biochemistry / Cardiovascular system / Chemical compounds / Chemistry / Chemistry and Materials Science / Chemistry/Food Science / Circulatory system / Density Functional Theory / Design / Diagnostic systems / Dyes / Emission / Emissions / Fluorescence / Fluorescent Dyes - chemical synthesis / Fluorescent Dyes - chemistry / Fluorophores / High resolution / Image contrast / Image resolution / Indolizines - chemical synthesis / Indolizines - chemistry / Infrared absorption / Infrared Rays / Inorganic Chemistry / Mice / Nanoemulsions / Optical Imaging / Organic Chemistry / Physical Chemistry / Principles / Quantum dots / Radiation / Short wave radiation / Silicon / Silicon - chemistry / Synthesis / Time dependence / Wavelength / Wavelengths