Amyloid-β (Aβ) fibrillization is described as a central event in the pathogenesis of Alzheimer’s disease (AD). Amyloid imaging is expected to play a pivotal role in early and differential diagnosis of dementias, and in the evaluation of anti-Aβ treatments. Luminescent conjugated oligothiophenes (LCO) have been proposed as optical biomarkers of protein fibrillation [1]. In this paper, we evaluated a fluorescent magnetic hybrid nanoprobe (HNP5011), based on gadolinium fluoride nanoparticles functionalized with luminescent conjugated polythiophenes moieties (Fig. 1). The aim of this study was to investigate its potential for molecular imaging in a rat model bearing intracerebral pre-aggregated Aβ peptides.