Synthesis and Growth Mechanism of Iron Oxide Nanowhiskers

Palchoudhury, Soubantika; An, Wei; Xu, Yaolin; Qin, Ying; Zhang, Zhongtao; Chopra, Nitin; Holler, Robert A.; Turner, C. Heath; Bao, Yuping

doi:10.1021/nl200136j

Cited by 93 publications

(115 citation statements)

References 53 publications

(95 reference statements)

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“…Iron oxide NPs were synthesized using our previously published method by decomposing the iron-oleate complex over 300°C in the presence of oleic acid and trioctylphosphine oxide (Palchoudhury et al, 2011a(Palchoudhury et al, , 2011b(Palchoudhury et al, , 2011cXu et al, 2011Xu et al, , 2012. The as-synthesized NPs were transferred from organic solvents to aqueous solution using a ligand exchange method (Xu et al, 2011(Xu et al, , 2014, where original hydrophobic coatings were replaced with hydrophilic ligands.…”

Section: Discussionmentioning

confidence: 99%

“…Iron oxide NPs were synthesized by heating up the iron oleate precursor (2.5 g, 2.8 mmol) in 1-octadecene (10 ml, 90%) in the presence of TOPO/OA (TOPO 0.2 g, 0.5 mmol, OA 0.22 ml, 0.7 mmol) following previously published procedures (Palchoudhury et al, 2011a(Palchoudhury et al, , 2011bXu et al, 2011). After a 2½ h reaction at 320°C, the NPs were washed with ethanol and hexane and collected for surface modification.…”

Section: Synthesis Of Iron Oxide Nanoparticlesmentioning

confidence: 99%

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The responses of immune cells to iron oxide nanoparticles

Sherwood

Lackey

et al. 2016

J of Applied Toxicology

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Immune cells play an important role in recognizing and removing foreign objects, such as nanoparticles. Among various parameters, surface coatings of nanoparticles are the first contact with biological system, which critically affect nanoparticle interactions. Here, surface coating effects on nanoparticle cellular uptake, toxicity and ability to trigger immune response were evaluated on a human monocyte cell line using iron oxide nanoparticles. The cells were treated with nanoparticles of three types of coatings (negatively charged polyacrylic acid, positively charged polyethylenimine and neutral polyethylene glycol). The cells were treated at various nanoparticle concentrations (5, 10, 20, 30, 50 μg ml À1 or 2, 4, 8, 12, 20 μg cm À2 ) with 6 h incubation or treated at a nanoparticle concentration of 50 μg ml À1 (20 μg cm À2 ) at different incubation times (6, 12, 24, 48 or 72 h). Cell viability over 80% was observed for all nanoparticle treatment experiments, regardless of surface coatings, nanoparticle concentrations and incubation times. The much lower cell viability for cells treated with free ligands (e.g.~10% for polyethylenimine) suggested that the surface coatings were tightly attached to the nanoparticle surfaces. The immune responses of cells to nanoparticles were evaluated by quantifying the expression of toll-like receptor 2 and tumor necrosis factor-α. The expression of tumor necrosis factor-α and toll-like receptor 2 were not significant in any case of the surface coatings, nanoparticle concentrations and incubation times. These results provide useful information to select nanoparticle surface coatings for biological and biomedical applications.

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Section: Discussionmentioning

confidence: 99%

Section: Synthesis Of Iron Oxide Nanoparticlesmentioning

confidence: 99%

The responses of immune cells to iron oxide nanoparticles

Sherwood

Lackey

et al. 2016

J of Applied Toxicology

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“…3a, region a) is due to the dissociation of two oleate ligands from ferric oleate, and the mass loss at 292-354°C (Fig. 3a, region b) is due to the dissociation of the remaining one oleate ligand, and the DTG curve peak areas ratio of the two mass loss region is close to 2:1 (Palchoudhury et al 2011). The mass loss at * 354°C is due to desorption of decomposed oleic acid ligands and evaporation of remaining organic components ( Fig.…”

Section: Characterization Of Ferric Oleatementioning

confidence: 89%

“…The peak at 1711 cm -1 is assigned either to the symmetric stretching vibration of free oleic acid or to the asymmetrical stretching vibration of unidentate carboxylate. The absorption peak at 733-723 cm -1 is assigned to the -(CH 2 ) n -(n C 4) of the long-alkyl side chain of the catalyst (Bronstein et al 2007;Palchoudhury et al 2011). Moreover, the coordination modes of the metal carboxylate can be deduced by the frequency difference between the antisymmetric and symmetric stretching vibration of m(COO -), D, in the range of 1300-1700 cm -1 .…”

Section: Characterization Of Ferric Oleatementioning

confidence: 99%

Aquathermolysis of heavy crude oil with ferric oleate catalyst

Wang

et al. 2018

Pet. Sci.

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Oil-soluble catalysts could be of special significance for reducing the viscosity of heavy crude oil, because of their good dispersion in crude oil and high catalytic efficiency toward aquathermolysis. Ferric oleate was synthesized and applied as catalyst in the aquathermolysis reaction of Shengli heavy oil. It was found that ferric oleate was more efficient for heavy oil cracking than Co and Ni oleates. Besides, it was superior to oleic acid and inorganic ferric nitrate and achieved the highest viscosity reduction rate of up to 86.1%. In addition, the changes in the components of Shengli heavy oil before and after aquathermolysis were investigated by elemental analysis, Fourier transform infrared spectrometry, and 1 H nuclear magnetic resonance spectroscopy. Results indicated that ferric oleate contributed to a significant increase in the content of light components and decrease in the content of resin, N and S. The as-prepared ferric oleate showed good activity for reducing the viscosity and improving the quality of the heavy crude oil, showing promising application potential in aquathermolysis of heavy crude oil.

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“…8 Recently, IONPs, by tuning their size and shape, have been used for positive (T 1 ) MRI contrast effects. 9,10 For biomedical applications, knowing the iron concentration is essential because of its toxicity. Knowing iron concentrations is also important because of the direct correlation of NP relaxivity and iron concentration when used as MRI contrast agents.…”

Section: Introductionmentioning

confidence: 99%

Development of an iron quantification method using nuclear magnetic resonance relaxometry

2017

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Biocompatibility has prompted a great amount of research in iron oxide nanoparticles (IONPs) as alternative magnetic resonance imaging (MRI) contrast agents. Iron concentration analysis is a key parameter to determine the relaxivities of IONPs as MRI contrast agents. Currently available methods for iron quantification are mainly inductively coupled plasma mass spectrometry (ICP-MS) and ferrozine-based iron assays. ICP spectrometry may not be easily accessible for routine analysis while iron assays are highly sensitive to sample preparation. In this paper, we present an alternative method for quantifying iron concentration using nuclear magnetic resonance (NMR) relaxometry, a technique commonly used for developing MRI contrast agents. To quantify iron concentration with NMR, a standard curve of relaxation rate versus iron concentrations was created to obtain the relaxivity of Fe3+ iron in solution. After dissolving IONPs in an acid, the iron concentration of the solution can be obtained using the relaxation times and the relaxivity of Fe3+ iron from the standard curve. The accuracy and sensitivity of this NMR method were verified by comparing with ICP analysis and ferrozine-based iron assays. Results indicate that this NMR method for iron concentration analysis was accurate for concentrations as low as 0.005 mM. In addition, the relaxivity of Fe3+ iron was sensitive to the type of acids to dissolve the IONPs, indicating that the same acid should be used for sample dissolution and the standard curve.

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Synthesis and Growth Mechanism of Iron Oxide Nanowhiskers

Cited by 93 publications

References 53 publications

The responses of immune cells to iron oxide nanoparticles

The responses of immune cells to iron oxide nanoparticles

Aquathermolysis of heavy crude oil with ferric oleate catalyst

Development of an iron quantification method using nuclear magnetic resonance relaxometry

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