IR-1048  (Synonyms: S01448)

IR-1048 is a nitroreductase (NTR)-responsive near-infrared fluorescence (NIR)/photoacoustic (PA) imaging probe and photothermal agent. IR-1048 is coupled with a nitroimidazole group to form IR-1048-MZ. IR-1048-MZ is catalytically reduced by NTR in a hypoxic environment, restoring strong near-infrared absorption and fluorescence emission (NIR II window), while activating the photothermal effect. IR-1048 relies on NTR-mediated electron transfer to relieve intramolecular fluorescence quenching, achieving specific imaging and photothermal ablation of tumor hypoxic areas. IR-1048 is mainly used for high-contrast NIR II/photoacoustic imaging and photothermal therapy research and tumor diagnosis of the tumor hypoxic microenvironment^[1][2].

IR-1048 needs to be modified with the MZ group (nitro imidazole) to form IR-1048-MZ, which has cell activity and is suitable for in vivo or in vitro experiments.

In the in vitro enzyme response experiment, the near-infrared II (NIR II) fluorescence intensity of IR-1048-MZ (5 μg/mL; incubated with NTR for 30 min) was enhanced 106.9 times after NTR-catalyzed reduction, the photoacoustic (PA) signal intensity increased from 121 to 936, and the photothermal effect increased the solution temperature from 30.4°C to 57.6°C^[1].

Experimental methods and procedures for the in vitro assay of IR-1048-MZ^[1]:
1. Cell culture
A549 cells (human lung cancer cells) were seeded at a density of 1×10⁴ cells/well in 96-well plates and incubated overnight.
2. Probe preparation
Cells were treated with IR-1048-MZ (5-20?? μg/mL) for 2 hours under hypoxic conditions (0% O₂) or normoxic conditions (20% O₂) with 500 μM NADH as a coenzyme to mimic intracellular NTR activity.
3. Fluorescence detection
NIR II fluorescence intensity was measured using a microplate reader with an excitation wavelength of 980 nm and an emission wavelength of 1046 nm.
A calibration was performed against a standard curve of NTR concentrations (0-10 μg/mL) to quantify enzyme activity.
4. Photoacoustic (PA) imaging
The treated cells were transferred into a photoacoustic imaging chamber.
Irradiated with 880 nm laser (pulsed, 100 mJ/cm²), and the photoacoustic signals were recorded using a 3D photoacoustic tomography system.
The signal intensity was analyzed to evaluate probe activation.
5. Photothermal (PT) effect evaluation
Cells were incubated with IR-1048-MZ (5 μg/mL) for 30 min under hypoxic conditions.
Irradiated with 980 nm near-infrared laser (0.1 W/cm²) for 2 min, and the temperature change was measured using an infrared thermal imager.

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

In vivo experiments in A549 tumor-bearing mice, IR-1048-MZ (40 μg/mL; 14 h after intravenous injection) achieves high-contrast NIR II fluorescence imaging through NTR activation, with a tumor-to-background signal ratio of 30. Irradiation with a 980 nm laser (0.1 W/cm², 2 min) raises the tumor temperature to 58°C, completely inhibiting tumor growth and preventing recurrence^[1].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

739.91

C₄₀H₃₈BCl₃F₄N₂

155613-98-2

Solid

Brown to black

[F-][B+3]([F-])([F-])[F-].ClC1=CC=C2C3=C(/C(N2CCCC)=C\C=C4C(Cl)=C(CCC\4)/C=C/C5=[N+](CCCC)C6=CC=C(Cl)C7=CC=CC5=C67)C=CC=C31

Room temperature in continental US; may vary elsewhere.

-20°C, sealed storage, away from moisture and light

*In solvent : -80°C, 6 months; -20°C, 1 month (sealed storage, away from moisture and light)

• [1]. Xiaoqing Meng, et al. Hypoxia-triggered single molecule probe for high-contrast NIR II/PA tumor imaging and robust photothermal therapy. Theranostics. 2018 Nov 15;8(21):6025-6034.  [Content Brief]

  [2]. Xiaoxu Kang, et al. Dual-Cascade Responsive Nanoparticles Enhance Pancreatic Cancer Therapy by Eliminating Tumor-Resident Intracellular Bacteria. Adv Mater. 2022 Dec;34(49):e2206765.  [Content Brief]