A Dual-Imaging Fluorescent and Iodinated Thermosensitive Hydrogel for Image-Guided Surgery of Pulmonary Nodules

The clinical demand for precise and minimally invasive pulmonary nodule localization continues to grow with the widespread adoption of minimally invasive surgery. To address the limitations of existing localization techniques, we develop a thermoresponsive hydrogel based on Pluronic F127, which undergoes a sol-gel transition at physiological temperature. This injectable formulation-termed ICG-Lipiodol thermosensitive hydrogel (ILTG)-is co-loaded with iodinated oil for computed tomography (CT) imaging and indocyanine green (ICG) for near-infrared (NIR) fluorescence imaging, enabling preoperative localization and dual-modal image-guided surgery. In addition to CT-guided localization, the iodinated oil enables deep-tissue imaging by compensating for the low penetration depth of ICG. Upon injection, the sol rapidly gels in situ, ensuring spatial confinement and prolonged retention of imaging signals at the tumor site. We evaluate the gelation temperature, mechanical properties, signal stability, and overall performance of the platform for preoperative localization and intraoperative imaging utilizing both rabbit and porcine lung models. The injectable dual-imaging marker, therefore, can serve as a powerful tool for surgical guidance beyond thoracic procedures.