title: Superparamagnetic iron oxide nanoparticles stabilized by a poly(amidoamine)-rhenium complex as potential theranostic probe.
abstract: Three-component nanocomposites, constituted by a superparamagnetic iron oxide core coated with a polymeric surfactant bearing tightly bound Re(CO)3 moieties, were prepared and fully characterized. The water soluble and biocompatible surfactant was a linear poly(amidoamine) copolymer (PAA), containing cysteamine pendants in the minority part (ISA23SH), able to coordinate Re(CO)3 fragments. For the synthesis of the nanocomposites two methods were compared, involving either (i) peptization of bare magnetite nanoparticles by interaction with the preformed ISA23SH-Re(CO)3 complex, or (ii) "one-pot" synthesis of iron oxide nanoparticles in the presence of the ISA23SH copolymer, followed by complexation of Re to the SPIO@ISA23SH nanocomposite. Full characterization by TEM, DLS, TGA, SQUID, and relaxometry showed that the second method gave better results. The magnetic cores had a roundish shape, with low dispersion (mean diameter ca. 6 nm) and a tendency to form larger aggregates (detected both by TEM and DLS), arising from multiple interactions of the polymeric coils. Aggregation did not affect the stability of the nano-suspension, found to be stable for many months without precipitate formation. The SPIO@PAA-Re nanoparticles (NPs) showed superparamagnetic behaviour and nuclear relaxivities similar or superior to commercial MRI contrast agents (CAs), which make them promising as MRI "negative" CAs. The possibility to encapsulate (186/188)Re isotopes (γ and β emitters) gives these novel NPs the potential to behave as bimodal nanostructures devoted to theranostic applications.
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133, Milano, Italy. daniela.maggioni@unimi.it.
authors.forename: Daniela
authors.initials: D
authors.lastname: Maggioni
authors.forename: Paolo
authors.initials: P
authors.lastname: Arosio
authors.forename: Francesco
authors.initials: F
authors.lastname: Orsini
authors.forename: Anna M
authors.initials: AM
authors.lastname: Ferretti
authors.forename: Tomas
authors.initials: T
authors.lastname: Orlando
authors.forename: Amedea
authors.initials: A
authors.lastname: Manfredi
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Ranucci
authors.forename: Paolo
authors.initials: P
authors.lastname: Ferruti
authors.forename: Giuseppe
authors.initials: G
authors.lastname: D'Alfonso
authors.forename: Alessandro
authors.initials: A
authors.lastname: Lascialfari
mesh_terms: D001610:Beta Particles; D003287:Contrast Media / Q000138:chemical synthesis / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry*; D052203:Ferrosoferric Oxide / Q000737:chemistry*; D005720:Gamma Rays; D008279:Magnetic Resonance Imaging; D058185:Magnetite Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D011073:Polyamines / Q000737:chemistry*; D011868:Radioisotopes; D012211:Rhenium / Q000737:chemistry*
chemical_list: D003287:Contrast Media; D056831:Coordination Complexes; D058185:Magnetite Nanoparticles; C531249:Poly(amidoamine); D011073:Polyamines; D011868:Radioisotopes; D012211:Rhenium; D052203:Ferrosoferric Oxide