"Interfacial Activation" High-Fidelity Sensing Strategy: Two-Photon Fluorescence Imaging of Transmembrane H₂S Release

Area of Science:

• Cell Biology
• Biochemistry
• Chemical Biology

Background:

• Accurate imaging of cell membrane events is crucial for understanding biological processes.
• Existing fluorescent tools lack specificity, causing background noise and reduced imaging quality.
• A novel strategy is needed to enhance signal localization at the cell membrane.

Purpose of the Study:

• To develop a novel "Interfacial Activation" strategy for high-fidelity cell membrane imaging.
• To engineer a specific probe for detecting transmembrane hydrogen sulfide (H2S).
• To demonstrate the probe's utility in live biological systems.

Main Methods:

• Designed NACP, an amphiphilic two-photon fluorophore utilizing aggregation-caused quenching (ACQ) for signal activation.
• Engineered NACP-DBS, a dual-gated probe for targeted outer-membrane localization.
• Utilized two-photon microscopy for imaging H2S dynamics in vitro and in vivo.

Main Results:

• NACP-DBS exhibited strong fluorescence enhancement upon insertion into the lipid bilayer.
• The probe demonstrated high sensitivity (LOD = 6.7 nM) and near-infrared emission (643 nm).
• Successfully monitored endogenous H2S in living cells, mouse models, and deep tissue with high contrast.

Conclusions:

• The "Interfacial Activation" strategy provides a robust platform for developing advanced membrane-sensing tools.
• NACP-DBS enables high-fidelity, wash-free imaging of transmembrane H2S.
• This approach facilitates deeper understanding of transmembrane signal transduction pathways.