Optical coherence tomography (OCT) is standard-of-care retinal imaging technique used in the clinic to diagnose and monitor diseases such as age-related macular degeneration (AMD), glaucoma, and diabetic retinopathy. It is also widely employed to study retinal diseases in pre-clinical research in animal models where OCT is used to investigate new retinal therapies and understand disease progression. While the strength of OCT is its ability to visualize individual retinal layers, image contrast is hindered when the retinal layers are severely disturbed such as in neovascularization and in biological tissues with high reflectivity. Moreover, it is a poor candidate for imaging at the molecular level because its source of contrast, scattering from changes in the refractive index of materials, does not change significantly between molecules such as antibodies and proteins. While strong absorbing agents such as organic dyes have enhanced the OCT contrast there are still limitations particularly in tissue with neovascularization and very few are FDA approved. Recently, the potential of gold nanoparticles as exogenous contrast agents and drug carriers in the eye was assessed and the OCT signal was found to be very dependent on changes in the refractive index of the material and on the nanoparticle (absorber) concentration. Consequently, to fully assess the <i>in vivo</i> application of nanomaterials as contrast agents, we need to improve the gap in our understanding of the specific inherent nanoparticle features that drive nanoparticle stability, nanomaterial-biological interactions (NBI), biouptake, toxicity, and changes in the index of refraction or reflectivity in highly scattering environments. Here we will discuss the design biomimetic gold nanomaterials and the how their physicochemical features (shape, size, composition, surface coating and charge) affect cellular uptake efficiency. We expect that increased uptake in cells will lead to increase absorber concentration and significant changes in refractive index to enhance image contrast at the molecular level <i>in vivo</i> using OCT.

Nanomaterials for enhancing the resolution of optical coherence tomography in the retina

255th National Meeting (2018)

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