KLVFF oligopeptide-decorated amphiphilic cyclodextrin nanomagnets for selective amyloid beta recognition and fishing

Recognition and capture of amyloid beta (Ab) is a challenging task for the early diagnosis of neurodegenerative
disorders, such as Alzheimer’s disease. Here, we report a novel KLVFF-modified nanomagnet
based on magnetic nanoparticles (MNP) covered with a non-ionic amphiphilic b-cyclodextrin (SC16OH) and decorated with KLVFF oligopeptide for the self-recognition of the homologous amino-acids sequence of AB to collect AB (1-42) peptide from aqueous samples. MNP@SC16OH and MNP@SC16OH/Ada-Pep nanoassemblies were fully characterized by complementary techniques both as solid powders and in aqueous dispersions. Single domain MNP@SC16OH/AdaPep nanomagnets of 20-40 nm were observed by TEM analysis. DLS and -potential measurements revealed that MNP@SC16OH nanoassemblies owned in aqueous dispersion a hydrodynamic radius of about 150 nm, which was unaffected by Ada-Pep decoration, while the negative -potential of MNP@SC16OH (-40 mV) became less negative (-30 mV) in MNP@SC16OH/Ada-Pep, confirming the exposition of positively charged KLVFF on nanomagnets surface. The ability of MNP@SC16OH/Ada-Pep to recruit AB (1-42) in aqueous solution was evaluated by MALDI-TOF and compared with the ineffectiveness of undecorated MNP@SC16OH and VFLKF scrambled peptide-decorated nanoassemblies (MNP@SC16OH/Ada-scPep), pointing out the selectivity of KLVFFdecorated nanohybrid towards AB (1-42). Finally, the property of nanomagnets to extract AB in conditioned medium of cells over-producing AB peptides was investigated as proof of concept of effectiveness of these nanomaterials as potential diagnostic tools.