X-ray µ-CT contrast agents employing highly-concentrated low-viscosity layered double hydroxide nanoparticles for high-resolution imaging of vasculature.

Contrast agents capable of being injected and cured in situ within the vasculature are required for angiography based on X-ray microcomputed tomography (µ-CT) for pathophysiology of biopsies or postmortem. In this study, we developed a contrast agent based on highly-concentrated methanolic dispersion of NiAl-type layered double hydroxide nanoparticles (NiAl-LDH NPs) for X-ray µ-CT imaging of vasculature. We optimized the synthesis conditions of the constituent NiAl-LDH NPs, with particular attention to drying conditions and dispersion media selection. The formulated contrast agent achieved a particle concentration >30 wt%, a curing time of ∼30 min, and low viscosity (<100 mPa s). These properties enabled successful perfusion into small vessels and capillaries giving excellent X-ray attenuation following setting without tissue maceration. Consequently, this enabled reliable vessel identification and segmentation using simple intensity-based approaches giving a robust approach to accelerated tissue screening.