Core–shell superparamagnetic nanoparticles with interesting properties as contrast agents for MRI

Abstract

h i g h l i g h t sCoreeshell nanoparticles with iron oxide cores and different coatings were obtained. The new nanosystems are efficient as negative contrast agent for MRI. The efficiency is discussed relating to the different coatings properties. Contrast enhancement is quantified in phantoms MRI and validated in an animal model. The potentiality of these new coreeshell NPs as negative CA for MRI is demonstrated and quantified. The longitudinal and transverse relaxivities of NPs with three different coating compositions were studied at a 7 T magnetic field: silica (TEOS), (3-aminopropyl) triethoxysilane (APTES) and (3-glycidoxypropyl) methyldiethoxysilane (GPTMS).Clearly, it was found that the coreeshell NPs efficiency as CA was strongly depend on the SPIONs coating.All the three coreeshell NPs studied presented a very small effect on the longitudinal relaxation time but a pronounced one on the transverse relaxation time, leading to a very high transverse longitudinal relaxivities ratio, decisive for their efficiency as negative CA for MRI.The effect of the coreeshell NPs on the MRI contrast enhancement is obtained and quantified in a set of MRI of agar phantoms obtained at 7 T magnetic field and with a imaging gradient field of 1.6 T/m. The coreeshell NPs were tested in Zebra-fish (Danio rerio) animal model. Zebra-fish MRI were obtained with animals injected with the three coreeshell NPs and the contrast enhancement validated.

Synthesis, characterization and luminescence of europium perchlorate with MABA‐Si complex and coating structure SiO2@Eu(MABA‐Si) luminescence nanoparticles

“…They have wide application in the manufacture of functional fluorescent materials, and in magnetic materials, electronics, medicine, etc. Research has concentrated on the methods of synthesizing coated NPs and new methods of fabricating coated materials with a nanostructure have gained considerable attention over the last few decades because of their unique properties and potential applications …”

Energetic electron processes fluorescence effects for structured nanoparticles X-ray analysis and nuclear medicine applications

“…Let us now consider Ormosil coated SPIO nanoparticles with a 6 nm diameter core nucleus of mostly Fe 2 O 3 and a silica/ORMOSIL coating, which has a rough average composition of Si 2 O 3 C 3 H 12 according to data from Peña Alonso et al [29], resulting in particles with a total radius of 66 nm with interesting characteristics as contrast agents for magnetic resonance imaging (MRI) [30]. If irradiated with a proton beam (either 3.0 MeV for analytical purposes or, say, 68 MeV for medical treatment purposes) or activated to contain a small amount of 57 Co, the core will emit Fe X-rays and Auger electrons in a ratio close to 1-2, since the K shell fluorescence coefficient of iron is x Fe K ¼ 0:34, while the outer shell will emit primary Si X-rays and Auger electrons in a ratio close to 1-20, since the silicon K shell fluorescence coefficient is x Si K ¼ 0:05 [12].…”

“…As mentioned earlier, the efficiency of the ideal target-specific radionuclide, or, in fact, any photon and/or electron emitting particle, depends largely on the number of electrons emitted, while taking care on the ratio of the emitted penetrating radiation and non-penetrating radiation [25]. The obtained analytical approximations, being [30] coated SPIO nanoparticles, having a Fe 2 O 3 6 nm diameter core nucleus and a 60 nm coating of silica/ORMOSIL (Si 2 O 3 C 3 H 12 according to Ref. [29]).…”

Liposil Nanocarriers for Pharmaceutical Applications: Synthesis Innovations

“…The first liposomes set are silica-coated by Stöber [7] methodology while the second set is silica-coated by a modified LaMer [13] protocol. LaMer optimization is performed within silica NPs model.…”

“…Finally the silica growth is carried out by a novel modified timesaving LaMer protocol, which stands on a sharp nucleation process, induced by a strong liquid supersaturation [13]. Only 2 hours are needed for the silica-coating step.…”