A Near-Infrared Fluorogenic Spray Probe for Rapid and Wash-Free Intraoperative Nerve Imaging

Area of Science:

• Biomedical Engineering
• Surgical Innovation
• Fluorescence Imaging

Background:

• Intraoperative nerve injury is a significant surgical complication.
• Current nerve visualization methods for fluorescence image-guided surgery (FIGS) lack spray compatibility and sufficient brightness.
• There is a need for rapid, wash-free nerve probes for enhanced surgical guidance.

Purpose of the Study:

• To develop and evaluate N4, a novel near-infrared fluorogenic spray probe for intraoperative nerve visualization.
• To assess N4's performance in terms of speed, wash-free application, and imaging quality.
• To demonstrate N4's utility in FIGS for peripheral nerve mapping.

Main Methods:

• Engineered N4 as a spirocyclic probe that becomes fluorescent upon enzymatic activation (MBP-triggered spiro-opening).
• Evaluated N4's turn-on fluorescence (6.3-fold increase) under physiological conditions.
• Applied N4 topically as a spray for visualizing sciatic and vagus nerves in surgical models, assessing nerve-to-muscle contrast and visualization of small nerve branches.

Main Results:

• N4 provides rapid (∼10 s), wash-free visualization of peripheral nerves.
• Achieved high nerve-to-muscle contrast (up to 6.4) for sciatic and vagus nerves.
• Successfully visualized nerve branches as small as 0.12 mm, even in blood-contaminated surgical fields.

Conclusions:

• N4 is a robust near-infrared fluorogenic spray probe enabling real-time FIGS nerve mapping.
• This probe significantly advances the development of next-generation surgical imaging tools.
• N4 offers a promising solution for reducing intraoperative nerve injury.