Therapeutic response of experimental choroidal neovascularization in mice with photodynamic/photothermal therapy using ICG loaded gold nanorods as a photosensitizer

We examined the efficacy of Indocyanine Green (ICG) loaded plasmonic gold nanorods (AuNP) assisted combined photothermal and photodynamic therapy for laser induced choroidal neovascularization (CNV) in pigmented mice. Eight C57BL/6 wild type pigmented mice were divided into two treatment groups. Each mouse received multiple 532 nm laser induced CNV in both eyes. Control mice were untreated while treatment group received intravenous injection of ICG loaded gold nanorods on day 7 prior to single near-infrared (NIR 808 nm) laser treatment session. For assessing progression of CNV lesion volume, in-vivo ocular imaging was performed on each animal at day 1, 7, and 14 using optical coherence tomography volumetric imaging. Early and late phase fluorescence angiography was performed for CNV leakage analysis. Infrared reflectance imaging and were used to analyze in-vivo laser injury and healing assessment. ICG-AuNP assisted combined photothermal/photodynamic therapy resulted in significantly increased healing and decreased fluorescein leakage at the CNV site compared to control mice who did not receive NIR laser treatment. Enhanced permeability and retention of AuNP assists in localization of therapeutic agents to the CNV lesion, which allows for targeted therapy while minimizing laser induced damage to healthy tissues.