High-sensitivity contrast-enhanced in vivo imaging with optical coherence tomography (OCT)

We developed custom spectral detection algorithms and highly-scattering large gold nanorods for sub-nanomolar sensitivity contrast-enhanced optical coherence tomography (OCT). We used this approach for noninvasive 3D imaging of blood and lymph vessels in living mice.

1. Introduction

Optical Coherence Tomography (OCT) [1] uses low-coherence interferometry to provide micron-scale spatial resolution and millimeter-scale depth of penetration, making it a potential candidate for functional and molecular imaging of living animals with cellular resolution. Several studies have attempted to adapt OCT as a molecular imaging modality by using a variety of nanoparticles, most commonly gold nanorods (GNRs) [2]. However, the total optical extinction of these particles is dominated by absorption rather than scattering [3], leading to poor OCT contrast and decreased sensitivity. Larger GNRs (LGNRs) with enhanced scattering cross-sections could potentially achieve the signal-to-background ratio necessary to realize the advantages of OCT with molecular contrast.