Abstract
Targeted imaging of the lymphatic system is essential for the early diagnosis and management of lymphatic disorders, such as lymphedema. In this study, we developed a lymphatic-targeted fluorescent nanoprobe by encapsulating indocyanine green (ICG) within poly(lactic-co-glycolic acid) (PLGA) nanoparticles, further surface-modified with hyaluronic acid-polyethylene glycol (HA-PEG) to enhance specificity (HA-PEG-ICG/PLGA NPs). The nanoparticles were synthesized via a microemulsion technique followed by surface cross-linking, and thoroughly characterized by ultraviolet-visible (UV-vis) spectroscopy, fluorescence emission analysis, Fourier transform infrared (FTIR) spectroscopy, and ζ-potential measurements, confirming their physicochemical stability and functionalization. In vitro cytotoxicity assays indicated excellent biocompatibility with both human keratinocytes (HaCaT) and mouse lymphatic endothelial cells (SVEC4-10). Confocal microscopy and quantitative fluorescence analyses revealed significantly enhanced uptake of HA-PEG-ICG/PLGA NPs in SVEC4-10 cells, which was attributed to HA-mediated binding to LYVE-1 receptors. In vivo imaging in C57BL/6JCrlBltw mice further demonstrated prolonged retention and selective fluorescence accumulation in lymphatic vessels following intraperitoneal administration, surpassing those of free ICG and ICG/PLGA controls. Collectively, these results confirm the potential of HA-PEG-ICG/PLGA NPs as a safe and effective nanoplatform for real-time lymphatic imaging. This targeted system holds promises for early lymphedema diagnosis, intraoperative lymphatic mapping, and future integration with theragnostic strategies for lymphatic-associated diseases.