Controllable delivery of peptides by superparamagnetic Fe3O4/slica nanoparticle vehicles

Superparamagnetic core/shell nanoparticles, composed of Fe3O4 cores and biocompatible slica shells, have been utilized as a nano-vehicle for the delivery of peptides. The silica shells with amine groups were functionalized with 1,2-cyclohexanedicarboxylic anhydride as click linkers, forming pH-sensitive amides and terminal carboxylic groups for the conjugation and release of bradykinin B1 receptor antagonist (R-954) peptides. The results show that the loading capacity of R-954 can reach up to 19.8 wt.% of the total mass of Fe3O4/silica/R-954 nanoparticles, which is far higher than non-chemical binding adsorption (1.2 wt.%). In this case, ∼92.3% peptides could be released at pH 5.0 for about 5 h, while only 10.2% occured at pH 7.4. Meanwhile such nanovehicles present a monodispersibility in aqueous solution and thus have a great potential for their use as delivery systems.