Gold Nanorod Enhanced Photoacoustic Microscopy and Optical Coherence Tomography of Choroidal Neovascularization

Visualization and
evaluation of choroidal neovascularization (CNV)
are major challenges to improve treatment outcomes for patients with
age-related macular degeneration (AMD). Limitations of current imaging
techniques include the limited penetration depth, spatial resolution,
and sensitivity and difficulty visualizing CNV from the healthy microvasculature.
In this study, a custom-built multimodal photoacoustic microscopy
(PAM) and optical coherence tomography (OCT) system was developed
to distinguish the margin of CNV in living rabbits with the assistance
of functionalized gold nanorods conjugating with RGD ligands (GNR-RGD).
Intravenous administration of GNR-RGD into rabbits in a CNV model
resulted in signal enhancements of 27.2-fold in PAM and 171.4% in
OCT. This molecular imaging technique of contrast-enhanced PAM and
OCT is a promising tool for the precise imaging of CNV as well as
the evaluation of the pathophysiology in vivo without
destruction of tissue.