Abstract
Fluorescence imaging in the second near-infrared window (NIR-II) allows visualization of deep anatomical features with an unprecedented degree of clarity. NIR-II fluorophores draw from a broad spectrum of materials spanning semiconducting nanomaterials to organic molecular dyes, yet unfortunately all water-soluble organic molecules with >1,000 nm emission suffer from low quantum yields that have limited temporal resolution and penetration depth. Here, we report tailoring the supramolecular assemblies of protein complexes with a sulfonated NIR-II organic dye (CH-4T) to produce a brilliant 110-fold increase in fluorescence, resulting in the highest quantum yield molecular fluorophore thus far. The bright molecular complex allowed for the fastest video-rate imaging in the second NIR window with ∼50-fold reduced exposure times at a fast 50 frames-per-second (FPS) capable of resolving mouse cardiac cycles. In addition, we demonstrate that the NIR-II molecular complexes are superior to clinically approved ICG for lymph node imaging deep within the mouse body.
Highlights
Fluorescence imaging in the second near-infrared window (NIR-II) allows visualization of deep anatomical features with an unprecedented degree of clarity
CH-4T was purified with high-performance liquid chromatography (HPLC) and the eluted fractions analysed by matrix-assisted laser desorption ionizing time-of-flight mass spectrometry (MALDI-TOF-MS) to collect CH1055 conjugated to four taurine moieties (Supplementary Fig. 1)
The relative fluorescent brightness of CH-4T was investigated by matching the absorbance at 808 nm (optical density (OD) 0.1) in deionized water (DI), phosphatebuffered solution (PBS) and fetal bovine serum (FBS) and imaging the vials on an indium-gallium-arsenide (InGaAs) camera under 808 nm excitation
Summary
Fluorescence imaging in the second near-infrared window (NIR-II) allows visualization of deep anatomical features with an unprecedented degree of clarity. We report tailoring the supramolecular assemblies of protein complexes with a sulfonated NIR-II organic dye (CH-4T) to produce a brilliant 110-fold increase in fluorescence, resulting in the highest quantum yield molecular fluorophore far. The bright molecular complex allowed for the fastest video-rate imaging in the second NIR window with B50-fold reduced exposure times at a fast 50 frames-per-second (FPS) capable of resolving mouse cardiac cycles. We demonstrate that changing the functional groups from carboxylic to sulfonic acid results in a completely watersoluble organic NIR-II dye (CH-4T) that readily forms supramolecular assemblies with plasma proteins to produce a brilliant increase in fluorescent brightness[18]. Optimizing the brightness of CH-4T through protein complexation prior to injection allowed for the fastest video-rate imaging in the NIR-II with B1.5–2 ms exposure times and ultra-fast 50 frames-per-second (FPS) dynamic imaging capable of resolving cardiac cycles with unprecedented temporal resolution. We demonstrate that lymph nodes deep within the mouse (B5–8 mm) are clearly imaged in the NIR-II using the CH-4T complex with imaging performance superior to indocyanine green (ICG)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
