BBB-Permeable Near-Infrared Oxazine Fluorophores for White Matter Tract Imaging

Preserving critical functional tissue remains a major challenge in fluorescence-guided surgery (FGS), particularly in neurosurgery where injury to white matter tracts can lead to lasting neurological deficits. Probes for preventing iatrogenic injury of the peripheral nervous system have highlighted the potential of real-time intraoperative guidance for nerve-sparing surgery, supporting improved preservation of critical functional tissue, but analogous tools for the central nervous system remain limited. While there are some awake mapping and MRI based techniques that try to minimize the resection of white matter tracts (WMTs), they do not provide surgeons with real-time visualization. To address this gap, we rationally translated a peripheral nerve targeted oxazine fluorophore platform into a library of novel oxazine dyes that can penetrate the blood-brain barrier (BBB), exhibit specificity for white matter tissue and maintain spectral compatibility with clinically relevant imaging systems. Guided by our fluorophore medicinal chemistry platform, this work includes library design, photophysical property characterization, in vivo WMTs specificity screening, and in vivo imaging window assessment of the lead candidates to evaluate neurosurgical workflow compatibility. The lead candidate identified from this library demonstrated strong in vivo WMTs-specific fluorescence intensity, contrast and imaging window compatible with neurosurgical workflows, establishing BBB-permeable oxazine fluorophores as a promising scaffold for future structure-sparing neurosurgical FGS.