Near-Infrared II Nanohybrid Enables Single-Excitation, Fully Ratiometric Imaging of Hydrogen Sulfide In Vivo

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Analytical Chemistry

Background:

• Hydrogen sulfide (H₂S) is a vital gasotransmitter involved in numerous physiological and pathological processes.
• Accurate in vivo monitoring of H₂S is essential for understanding its biological roles.
• Existing fluorescence imaging methods for H₂S often lack ratiometric probes operating in the second near-infrared (NIR-II) window.

Purpose of the Study:

• To develop a novel NIR-II ratiometric nanohybrid probe for precise in vivo H₂S detection.
• To overcome the limitations of current H₂S imaging systems.
• To establish a robust platform for advanced biosensing and diagnostics.

Main Methods:

• Synthesis of a NIR-II ratiometric nanohybrid (ErNPs@mSiO₂-Cy-NO₂) integrating Er³⁺-doped nanoparticles and a NIR-II cyanine dye.
• Utilizing a single 980 nm excitation wavelength for probe activation.
• Exploiting an intramolecular photoinduced electron-transfer (PET) process modulated by H₂S.
• Employing Er³⁺ emission at 1550 nm as an internal reference for ratiometric readout.

Main Results:

• The nanohybrid probe exhibited selective response to H₂S, converting Cy-NO₂ to Cy-NH₂.
• The probe enabled ratiometric detection within the NIR-II window (1026 nm/1550 nm).
• Real-time visualization of H₂S was achieved both in vitro and in vivo.

Conclusions:

• ErNPs@mSiO₂-Cy-NO₂ provides a robust platform for H₂S monitoring.
• The developed probe overcomes limitations of existing H₂S imaging techniques.
• This technology holds significant potential for future biosensing and diagnostic applications.