Direct monophasic replacement of fatty acid by DMSA on SPION surface

Gogoi, Madhulekha; Deb, Pritam; Vasan, Ganesh; Keil, P.; Kostka, Aleksander; Erbe, Andreas

doi:10.1016/j.apsusc.2012.06.011

Cited by 19 publications

(5 citation statements)

References 34 publications

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“…Hence, as for the case of Fe 3 O 4 @OA, it is likely that one of the carboxylate groups of DMSA molecules is capping the magnetite surface through the formation of a bridging bidentate complex with the available orbitals of the iron ions at the surface of the iron oxide, while the other one remains free pointing outward. Similar results were postulated by Mejías et al However, some other coexistent possibilities for coordination are not ruled out, like carboxylic groups either forming carboxylates at the surface, or pointing outward due to the coordination of sulfur atoms at the surface, as suggested in a previous report . Regarding this issue, further insights will be presented and discussed below from XPS data.…”

Section: Resultssupporting

confidence: 66%

Sorption of Gold by Naked and Thiol-Capped Magnetite Nanoparticles: An XPS Approach

et al. 2014

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Iron oxide nanoparticles are promising materials for many technological and environmental applications due to their versatile functionalization and magnetic properties that allow a facile remote control, separation and analyte recovery. In this contribution, the results of gold(III) sorption by naked and DMSA-capped (DMSA = m-2,3,dimercapto succinic acid) magnetite nanoparticles are discussed. Magnetite nanoparticles of 8 nm diameter were first synthesized by thermal decomposition of iron(III) oleate followed by a ligand exchange reaction to substitute oleic acid (OA) molecules by DMSA. Such systems of coated magnetite nanoparticles were characterized with Fourier transform infrared (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and magnetic measurements. FT-IR spectroscopy suggests that in Fe 3 O 4 @DMSA the organic coating is not homogeneous and it interacts with surface iron cations either through the carboxylate groups (by forming bridging bidentate complexes) or through disulfide bonds after oxidation of thiol groups. The magnetic measurements show that the nanoparticles are in the superparamagnetic range at room temperature despite the presence of dipolar interactions. The gold(III) adsorption isotherms for both bare Fe 3 O 4 and Fe 3 O 4 @DMSA nanoparticles were fitted with the Langmuir and Freundlich models. The better fit for the second model suggests the heterogeneous nature of the surface and the multilayer nature of gold adsorption. XPS spectra reveal that the adsorption of Au(III) ions comprises mostly its reduction to Au 0 by disulfide groups, although there is a fraction of these gold ions that is reduced directly onto the bare surface of the iron oxide leading to Fe(II) oxidation. According to the recorded optical absorption spectra, gold clusters of metallic character are also formed at the nanoparticle surface, a fraction of them forming subnanometer aggregates. The magnetic recovery of gold by this nanosystem could be extendable to other heavy metals.

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Section: Resultssupporting

confidence: 66%

Sorption of Gold by Naked and Thiol-Capped Magnetite Nanoparticles: An XPS Approach

et al. 2014

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“…6b shows the high resolution Fe2p, O1s and C1s spectra of both the samples. carboxylate oxygen atoms respectively [22]. However, there is clear variation in the relative intensities of these three peaks for the two samples, which could be due to the passivation effect of silica in the assembly sample and also the possibility of changing oleic acid binding configuration to the NPs surface.…”

Section: Surface Analysismentioning

confidence: 96%

Solvent evaporation driven entrapment of magnetic nanoparticles in mesoporous frame for designing a highly efficient MRI contrast probe

Saikia

Bhattacharya

Sen

et al. 2019

Applied Surface Science

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The present work reports a novel strategy of assembling maghemite (γ-Fe 2 O 3 ) nanoparticles (NPs) in mesoporous silica host for developing a highly efficient MRI contrast probe. Shrinkage of hydrophobic environment due to the continuous evaporation of chloroform fromChloroform-in-Water emulsions pushes the hydrophobic γ-Fe 2 O 3 NPs towards the hydrophobic pores of silica spheres resulting in a water soluble dense assembly structure.Mesoporous silica only with straight pores is found to be suitable for this particular entrapment process, while with curved and twisted pores, NPs are found to be seated on the surface only. So-developed assembly system has retained the superparamagnetic behaviour of its comprising NPs and exhibited high colloidal stability and biocompatibility. A significant 2 enhancement in MRI transverse relaxivity to 386.2 mM -1 s -1 from 191.8 mM -1 s -1 of isolated primary γ-Fe 2 O 3 NPs, has been obtained due to the strong magnetic field generated by the large number of NPs packed in the porous channels and consequent faster relaxation process.The fabrication strategy can be extended for the development of designed secondary nanostructures with new magnetic effects and physical properties.

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“…On the other hand, the replacement of the long‐chain molecules on the surface of the MNPs by the small and labile DMSA molecules brought the opposite result by decreasing the hydrodynamic size. The MNPs dispersed in aqueous medium owing to the free carboxylic groups (COO – ) of DMSA; additionally, the anchored carboxyl groups created a stable layer that was further stabilized through disulfide (S–S) cross‐linking amongst DMSA molecules 57. However, if excessive S–S bridging occurs, this modification entails the risk of the formation of a thick layer around the MNPs,58 which would cause relaxivity reduction.…”

Section: Resultsmentioning

confidence: 99%

Impact of the Presence of Octadecylamine on the Properties of Hydrothermally Prepared CoFe₂O₄ Nanoparticles

Georgiadou

Dendrinou‐Samara

2014

Eur J Inorg Chem

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CoFe 2 O 4 magnetic nanoparticles (MNPs) were synthesized in a new synthetic system from metal acetylacetonates in the presence of octadecylamine (ODA) in autoclaves with subcritical water. By altering the water extent and ratio of the precursors, four samples were isolated. High crystallinity MNPs of various sizes (26, 15, 18, 9 nm) and saturation magnetization (71, 87, 93, 64 emu g -1 ) were formed. The organic coating was characterized by FTIR spectroscopy, 1 H NMR and 13 C NMR spectroscopy, and thermogravimetric analysis (TGA), and the free amine groups were detected by a ninhy- [a]3645 drin assay. Under the present conditions, the CoFe 2 O 4 MNPs were covered by a bilayer consisting of N-octadecylamide and ODA. The MNPs were converted into fluorescence probes through the formation of a sulfonamide bond between ODA and sulforhodamine B (SRB). NMR relaxometric measurements were performed for MNPs modified with SRB, cetyltrimethylammonium bromide, and by 2,3-dimercaptosuccinic acid. The bimodal magnetic fluorescent MNPs showed relaxivity values of up to r 2 = 219.5 mM -1 s -1 , which renders them promising as dual agents.

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Direct monophasic replacement of fatty acid by DMSA on SPION surface

Cited by 19 publications

References 34 publications

Sorption of Gold by Naked and Thiol-Capped Magnetite Nanoparticles: An XPS Approach

Sorption of Gold by Naked and Thiol-Capped Magnetite Nanoparticles: An XPS Approach

Solvent evaporation driven entrapment of magnetic nanoparticles in mesoporous frame for designing a highly efficient MRI contrast probe

Impact of the Presence of Octadecylamine on the Properties of Hydrothermally Prepared CoFe₂O₄ Nanoparticles

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Direct monophasic replacement of fatty acid by DMSA on SPION surface

Cited by 19 publications

References 34 publications

Sorption of Gold by Naked and Thiol-Capped Magnetite Nanoparticles: An XPS Approach

Sorption of Gold by Naked and Thiol-Capped Magnetite Nanoparticles: An XPS Approach

Solvent evaporation driven entrapment of magnetic nanoparticles in mesoporous frame for designing a highly efficient MRI contrast probe

Impact of the Presence of Octadecylamine on the Properties of Hydrothermally Prepared CoFe2O4 Nanoparticles

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Impact of the Presence of Octadecylamine on the Properties of Hydrothermally Prepared CoFe₂O₄ Nanoparticles