Precise Surgical Navigation of Endometriosis via NIR-II Fluorescence Imaging With a Semiconducting Polymeric Probe

Endometriosis is a prevalent gynecological disorder characterized by ectopic growth of endometrial-like tissue, often causing chronic pain, infertility, and systemic inflammation. Accurate detection and complete surgical resection remain challenging because lesions are frequently small, multifocal, and visually ambiguous. Fluorescence imaging in the second near-infrared window (NIR‑II, 1000-1700 nm) enables deeper tissue visualization with reduced scattering and autofluorescence, offering improved contrast and spatial resolution. Here, we developed P‑BPTI, a NIR‑II-emissive semiconducting polymer designed to mitigate aggregation-caused quenching (ACQ) and enhance in vivo bioimaging. P‑BPTI nanoparticles exhibit strong NIR‑II fluorescence, excellent photostability, and deep tissue penetration. In a multi-lesion mouse model of endometriosis, P‑BPTI enabled noninvasive lesion visualization and real-time image-guided resection, outperforming both its monomeric counterpart and indocyanine green (ICG). Importantly, repeated administration of P-BPTI NPs at 7-day intervals enabled periodic NIR-II imaging of lesion status for up to 49 days after surgery. Post-operative histological analyses further supported effective lesion removal and reduced pathological activity. Overall, this work demonstrates the potential of P‑BPTI for NIR‑II image-guided surgery and long-term monitoring in endometriosis, with promise for improving lesion localization and therapeutic outcomes.