Bichromatic Imaging with Hemicyanine Fluorophores Enables Simultaneous Visualization of Non-alcoholic Fatty Liver Disease and Metastatic Intestinal Cancer

Abstract

Simultaneous detection of different diseases via a single fluorophore is challenging. We herein report a bichromatic fluorophore named Cy-914 for the simultaneous diagnosis of non-alcoholic fatty liver disease (NAFLD) and metastatic intestinal cancer by leveraging its NIR-I/NIR-II dualcolor imaging capability. Cy-914 with a pK a of 6.98 exhibits high sensitivity to pH and viscosity, showing turn-on NIR-I fluorescence at 795 nm in an acidic tumor microenvironment, meanwhile displaying intense NIR-II fluorescence at 914/1030 nm under neutral to slightly basic viscous conditions. Notably, Cy-914 could sensitively and noninvasively monitor viscosity variations in the progression of NAFLD. More importantly, it was able to simultaneously visualize NAFLD (ex/em = 808/1000−1700 nm) and intestinal metastases (ex/em = 570/810−875 nm) in two independent channels without spectral cross interference after topical spraying, further improving fluorescence-guided surgery of tiny metastases less than 3 mm. This strategy may provide an understanding for developing multi-color fluorophores for multidisease diagnosis.

“Dual‐Key‐and‐Lock” NIR‐II NSCyanines Enable High‐Contrast Activatable Phototheranostics in Extrahepatic Diseases

“…Unlike using synthesized diethylamino benzothiopyrylium and rhodamine‐based spirocyclic ring as pH recognition sites, [8a,b,11] commercially available 1,1,2‐trimethyl‐1H‐benzo[e]indole was exploited to regulate fluorescence emission under varied pH conditions due to the protonation or deprotonation. Besides, because of the flexible rotation feature, heptamethine chain was employed to adjust NSCyanines to sensitively respond to viscosity [14a,b] . The detailed synthesis procedure was described in Scheme S1 via one step Knoevenagel condensation reaction.…”

“…During the preparation of our manuscript, a pH/viscosity‐responsive NIR‐II dye (LET‐1052) with a p K a of 6.20 was reported, while the strongest NIR‐II fluorescence was observed in the liver of tumor‐bearing mice due to the complete lysosome activation [14c] . Recently, we also reported a pH/viscosity‐responsive dye (Cy‐914), which can visualize different diseases after topical spraying [14b] . Nevertheless, this probe is not suitable for i. v. injection, because it can easily accumulate and turn on its NIR‐I fluorescence in the normal liver due to the high p K a of 6.98.…”

BOIMPY-Based NIR-II Fluorophore with High Brightness and Long Absorption beyond 1000 nm for In Vivo Bioimaging: Synergistic Steric Regulation Strategy

“…Furthermore, significant bioluminescence signals were also observed in the belly and further verified the tumors (Figures b and S22). Next, the peritoneum was opened, and the visible tumors and suspected small metastatic tumors were all clearly visualized and precisely excised by harnessing high-resolution NIR-II fluorescence-guided surgery. ,, Meanwhile, no bioluminescence and NIR-II fluorescence signals were observed after the resection (Figures b, S21, and S22). Notably, several tiny metastatic tumors of less than 1 mm that were not visible by naked eyes were also visualized by NK1143-SC12-NPs and further identified by hematoxylin–eosin (H&E) staining (Figure c and d).…”

Near-Infrared Ratiometric Hemicyanine-Based pH Fluorescence Probe with Bone Targetability for Monitoring Bone Resorption

“…Intensity-based pH-responsive fluorescence probes with an ON/OFF switch use the enhancement or quenching of the probe fluorescence signal before and after exposure to H + to visualize the pH changes in a specific range. ,, Certainly, these probes have been widely used for the detection of bone resorption via implementing intravital imaging of osteoclasts activity on the surface of the bone tissue or in the deep bone matrix owing to their high sensitivity, good specificity, and in situ and real-time monitoring. ,, However, they have a few shortcomings such as susceptibility to interference from probe concentration, laser signal intensity, etc. , Diversely, the ratiometric pH-responsive fluorescence probe with dual absorption or emission wavelengths allows self-calibration of the two bands and excludes most environmental variables like probe concentration, instrumental parameters, photobleaching, etc., which can provide a quantitative analysis of the pH. − Thus, ratiometric pH fluorescence probes have greater advantages in the detection of bone resorption activity. As a ratiometric pH fluorescent probe molecule, hemicyanine (Hcy) dyes, due to their excellent optical properties such as high absorption coefficients, high fluorescence quantum yields, modifiability of terminal groups, and adjustable excitation and emission wavelengths, have attracted great interest from researchers and have been widely used to design near-infrared ratimetric pH fluorescence probes for monitoring of biological events in live cells or tissues. − Consequently, hemicyanine is highly anticipated to detect the bone resorption activity. In addition, as a probe for monitoring the bone resorption activity, its bone-binding ability is critical, as it may directly affect the efficiency and feasibility of the detection.…”