The aggregation of amyloid-β peptide (Aβ) is implicated in the pathology of Alzheimer's disease (AD), and Aβ oligomers are considered the most toxic species. Therefore, the detection and clearance of Aβ oligomers are crucial for the theranostic strategies for AD. However, effective methods for the detection of Aβ oligomers are rare, and only few of the oligomer-specific sensors have therapeutic functions as well. Recent studies have demonstrated that the toxicity of Aβ oligomers is related to the number of exposed hydrophobic residues. In this study, an oligomer-specific fluorescent probe, which was based on the hydrophobic regions that are exposed on Aβ oligomer surfaces was designed and synthesized. For improving the ability to recognize Aβ oligomers, the in situ treatment of AD symptoms and the ability to penetrate the blood-brain barrier, the probe and KLVFF peptide (an Aβ-target peptide) were modified on the surfaces of magnetic nanoparticles (MNP@NFP-pep). This complex could detect Aβ oligomers specifically, and achieve the wireless deep magnetothermally mediated disaggregation of Aβ aggregates with an alternating magnetic field. This work provides new insights into the development of a "sense and treat" system for AD therapy.

Recent clinical and epidemiological research has shown that insulin is associated with the pathological mechanisms of Alzheimer's disease (AD) and can protect against the oxidative stress triggered by amyloid-β peptide (Aβ). Herein, we present a systematic study on how the cross-fibrillation of insulin and Aβ is influenced by the surface chirality of an interface designed to mimic their aggregation on the cytomembrane. Intriguingly, the surface chirality strongly affected the aggregation kinetics, structure, morphology, and cellular responses of the cross-aggregates of insulin and Aβ. On a D-phenylalanine-modified surface, Aβ induced insulin to co-aggregate into β-sheet-rich fibrils and cross-fibrils that showed a pronounced cellular toxicity. However, on an L-phenylalanine-modified surface, insulin and Aβ formed non-toxic amorphous aggregates. Our work indicates that surface chirality can influence the cross-fibrillation of Aβ and insulin as well as the cytotoxicity of their aggregates.