Ultrasmall T1-T2 Magnetic Resonance Multimodal Imaging Nanoprobes for the Detection of β-amyloid Aggregates in Alzheimer's Disease Mice

Alzheimer's disease (AD) is an irreversible brain disorder and imposes a severe burden upon patients and the public health system. Most research efforts have focused on the search for effective therapeutic drugs, but it is time to pursue efficient early diagnosis based on the reasonable assumption that AD may be easier to prevent than reverse. Recent studies have shown that there are several probes for detecting amyloid-beta (A beta) plaques, one of the neuropathological hallmarks found in AD brain. However, it is still a great challenge for nonradioactive, sensitive detection and location of A beta plaques by brain imaging with high spatial resolution. Herein, phenothiazine derivative (PZD)-conjugated sub-5 nm ultrasmall ferrite nanoprobes (UFNPs@PEG/PZD) are designed and prepared for efficient T-1 -T-2 magnetic resonance multimodal imaging of A beta plaques. UFNPs@PEG/PZD not only possess high binding affinity to A beta plaques but also exhibit excellent properties of r(1) and r(2) relaxivities. This study thus provides a promising ultrasmall nanoplatform as an A beta-targeting multimodal imaging probe for the application of early diagnosis of AD.