Biocompatible GdIII-functionalized fluorescent gold nanoclusters for optical and magnetic resonance imaging

Abstract

Fluorescent gold nanoclusters are ideal building blocks for the construction of multimodal imaging probes, but their use for optical and magnetic resonance imaging (MRI) has remained unexplored. Here we propose the use of bovine serum albumin stabilized gold nanoclusters as bimodal MRI/optical nanoprobes by covalently grafting Gd-DTPA onto the fluorescent gold nanoclusters. These nanoprobes show a higher relaxivity of 23.7 mM⁻¹ s⁻¹ per Gd³⁺ relative to clinical Gd-DTPA (4.3 mM⁻¹ s⁻¹), while their fluorescence emission intensity is preserved. Fluorescence imaging and T₁-weighted magnetic resonance imaging further reveal that these nanoprobes are highly suited for dual modality imaging application. This paves the way for investigating the gold nanocluster-based nanoprobes in a variety of imaging applications.