Surface enhanced fluorescence effect improves the in vivo detection of amyloid aggregates.

The β-amyloid (Aβ) peptide is one of the key etiological agents in Alzheimer's disease (AD). The in vivo detection of Aβ species is challenging in all stages of the illness. Currently, the development of fluorescent probes allows the detection of Aβ in animal models in the near-infrared region (NIR). However, considering future applications in biomedicine, it is relevant to develop strategies to improve detection of amyloid aggregates using NIR probes. An innovative approach to increase the fluorescence signal of these fluorophores is the use of plasmonic gold nanoparticles (surface-enhanced fluorescence effect). In this work, we improved the detection of Aβ aggregates in C. elegans and mouse models of AD by co-administering functionalized gold nanorods (GNRs-PEG-D1) with the fluorescent probes CRANAD-2 or CRANAD-58, which bind selectively to different amyloid species (soluble and insoluble). This work shows that GNRs improve the detection of Aβ using NIR probes in vivo.