Nanomagnets based on Peptides-decorated Cyclodextrin for Amyloid-? targeting

Magnetic nanoparticles (MNPs) are widely utilized in magnetic-field-assisted bio-separation, bio- interaction, imaging and drug delivery, due to their large surface area and easy manipulation by an external magnetic force. Nanomagnets constituted by polymers, dendrimers and cyclodextrins functionalizing magnetite have been widely developed for therapy and diagnosis.1-2 Amphiphilic cyclodextrin (aCD) are largely employed to deliver different types of therapeutic and diagnostic molecules.3-4 Here we propose novel nanomagnets based on non ionic amphiphilic cyclodextrin heptakis (2-oligo(ethyleneoxide)-6-hexadecylthio-)-?-CD (SC16OH) -capping Fe3O4 NPs and decorated with Adamantanil-(PEG)4-KLVFF, (Ada-Pep), as nanoconstructs based on the self-recognizing sequence of the Amyloid-? (A?) peptides. Fe3O4@SC16OH was prepared by mixing Fe3O4 NPs with an aqueous dispersion of SC16OH and then isolated by settling down with a magnet. Fe3O4@SC16OH/Ada-Pep was prepared by hydration of an organic film of Ada-Pep, and isolated by centrifugation. In order to assess the recognition properties of the KLVFF active peptide, a magnetic cyclodextrin decorated with the scrambled units adamantanil-(PEG)4VFLKF (Ada-PepSCR) was fabricated. Peptide-tailored nanomagnets were characterized at solid state by TGA, STEM, AFM, X-Ray Diffraction, XPS and magnetization mass measurements. In aqueous physiological solutions, DLS and Z-potential measurements, point out a size of @200 nm and a negative surface potential ( -30 mV) dependently by the co-presence of aCD olygoethylenglycol chains and peptide units on the external fringe. The ability of these novel nanomagnets to target the A? peptides was studied either in A? containing aqueous samples by means of Maldi-Tof-Ms or in the medium of cultured cells over-expressing the A? peptides, by using an ELISA based assay. Our results indicate that in both the experimental conditions the nanomagnets can perform an unbiased A?-targeted fishing, thereby suggesting their potential use as efficient diagnostic agents.