In vivo photothermal optical coherence tomography in the mouse eye (Conference Presentation)

Abstract

OCT has become a standard in retina imaging at the pre-clinical and clinical level by allowing non-invasive, three-dimensional imaging of the tissue structure. However, OCT lacks specificity to contrast agents that could be used for in vivo molecular imaging. We have performed in vivo photothermal optical coherence tomography (PTOCT) of gold nanorods in the mouse retina after the mice were injected intravenously with the contrast agent. To our knowledge, we are the first team to perform PTOCT in the eye. Four lesions were induced by laser photocoagulation in each mouse retina (n=6 mice) and gold nanorods (untargeted and targeted with anti-mouse CD102 antibody, which labels neovasculature, peak absorption λ=750nm) were injected intravenously by tail-vein injection five days later in four mice (two mice are controls). The mice were imaged with PTOCT the same day. Our instrument is a spectral domain OCT system (λ=860nm) with a Titanium:Sapphire laser (λ=750nm) added to the beam path using a 50:50 splitter to target the gold nanorods. We acquired PTOCT B-scans over one lesion per mouse eye. There was a significant increase in photothermal intensity at the center of the lesion in the gold nanorod group versus the control group. This experiment demonstrates the feasibility of PTOCT to image the distribution of contrast agents in the mouse retina. In the future we will use this method to optimize drug delivery to the retina in pre-clinical models.