Direct correlation of PNIPAM thermal transition and magnetic resonance relaxation of iron oxide nanoparticles

This review discusses several aspects regarding ultrasmall magnetic nanoparticles asT1contrast agents, including synthesis, parameters affectingT1, and applications.

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Preparation and Characterisation of Highly Stable Iron Oxide Nanoparticles for Magnetic Resonance Imaging

Journal of Nanomaterials ◽

10.1155/2017/7859289 ◽

2017 ◽

Vol 2017 ◽

pp. 1-8 ◽

Cited By ~ 13

Author(s):

David Kovář ◽

Aneta Malá ◽

Jitka Mlčochová ◽

Michal Kalina ◽

Zdenka Fohlerová ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Iron Oxide ◽

Magnetic Nanoparticles ◽

Magnetic Resonance ◽

Iron Oxide Nanoparticles ◽

Superparamagnetic Iron Oxide ◽

Injection Rate ◽

Oxide Nanoparticles ◽

Resonance Imaging ◽

Average Size

Magnetic nanoparticles produced using aqueous coprecipitation usually exhibit wide particle size distribution. Synthesis of small and uniform magnetic nanoparticles has been the subject of extensive research over recent years. Sufficiently small superparamagnetic iron oxide nanoparticles easily permeate tissues and may enhance the contrast in magnetic resonance imaging. Furthermore, their unique small size also allows them to migrate into cells and other body compartments. To better control their synthesis, a chemical coprecipitation protocol was carefully optimised regarding the influence of the injection rate of base and incubation times. The citrate-stabilised particles were produced with a narrow average size range below 2 nm and excellent stability. The stability of nanoparticles was monitored by long-term measurement of zeta potentials and relaxivity. Biocompatibility was tested on the Caki-2 cells with good tolerance. The application of nanoparticles for magnetic resonance imaging (MRI) was then evaluated. The relaxivities (r1,r2) and r2/r1 ratio calculated from MR images of prepared phantoms indicate the nanoparticles as a promising T2-contrast probe.

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Efficient Synthesis of Water-Soluble Magnetic Nanoparticles and Its Application in MRI in the Detection of Intracranial Aneurysm

Science of Advanced Materials ◽

10.1166/sam.2021.4108 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1699-1707

Author(s):

Boya Li ◽

Aihua Xiong ◽

Xiaotong Yang ◽

Qiong Yang ◽

Jing Liu

Keyword(s):

Iron Oxide ◽

Magnetic Nanoparticles ◽

Magnetic Resonance ◽

High Resolution ◽

Intracranial Aneurysm ◽

Iron Oxide Nanoparticles ◽

Water Soluble ◽

Oxide Nanoparticles ◽

Aneurysm Wall ◽

The Impact

Magnetic nanoparticles were used in medical images, which could further improve image clarity, while watersoluble nanoparticles put forward more new requirements for the biocompatibility of nanoparticles. This research adopted a simple and novel method to prepare water-soluble iron oxide nanoparticles. First, transmission electron microscope (TEM) was used to analyze the size distribution of the prepared product; X-ray diffraction (XRD) was used to test the crystal structure of the prepared sample; the fast Fourier transform (FFT) spectrum was introduced to analyze the structural properties of the nanoparticles; the nanoparticle aqueous solutions of different concentrations were designed, and the impact of water-soluble nanoparticles on magnetic resonance imaging (MRI) was examined with the nuclear magnetic resonance spectrometer. At the same time, the prepared water-soluble nanoparticle solution was used for high-resolution tumor wall imaging of patients with unruptured intracranial aneurysm (IA) to compare the imaging effect of the aneurysm wall before and after the introduction of nanoparticles. In the material characterization test of nanoparticles, the prepared samples did not have certain iron oxide characteristic peaks, which means the synthesized iron oxide nanoparticles did not have a fixed crystal morphology. The samples tested by energy dispersive spectrometer (EDS) also contained Fe, O, C and Na. The average particle size was 5.8 nm. It was found under high-resolution TEM that the particle mirror spacing was 0.48 nm, which was consistent with the 111-crystal plane of Fe3O4; The magnetic hysteresis loop test confirmed that when the concentration of nanoparticles increased, the solution would form a magnetic fluid. When the concentration of aqueous solution of nanoparticles increased, the corresponding MRI signal would be significantly enhanced. It was used in the MR scan of patients with unruptured IA. Nanoparticle solution could increase the visibility of the aneurysm, and the image quality of the aneurysm wall could be significantly enhanced.

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Magnetic resonance imaging quantification and biodistribution of magnetic nanoparticles using T1-enhanced contrast

Journal of Materials Chemistry B ◽

10.1039/c7tb03129g ◽

2018 ◽

Vol 6 (10) ◽

pp. 1470-1478 ◽

Cited By ~ 3

Author(s):

Y. B. Lv ◽

P. Chandrasekharan ◽

Y. Li ◽

X. L. Liu ◽

J. P. Avila ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Iron Oxide ◽

Magnetic Nanoparticles ◽

Magnetic Resonance ◽

Contrast Agents ◽

Iron Oxide Nanoparticles ◽

Relaxation Times ◽

Oxide Nanoparticles ◽

Resonance Imaging

Monodispersed 4 nm Gd-doped iron oxide nanoparticles (GdIONPs) were fabricated, and were as T1-weighted contrast agents to confirm the feasibility of non-invasively quantify and monitor IONPs in vivo based on MRI longitudinal relaxation times.

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Evaluation of Surface-modified Superparamagnetic Iron Oxide Nanoparticles to Optimize Bacterial Immobilization for Bio-separation with the Least Inhibitory Effect on Microorganism Activity

Nanoscience &Nanotechnology-Asia ◽

10.2174/2210681208666181015120346 ◽

2020 ◽

Vol 10 (2) ◽

pp. 166-174

Author(s):

Mehdi Khoshneviszadeh ◽

Sarah Zargarnezhad ◽

Younes Ghasemi ◽

Ahmad Gholami

Keyword(s):

Iron Oxide ◽

Amino Acid ◽

Magnetic Nanoparticles ◽

Iron Oxide Nanoparticles ◽

Surface Coating ◽

Superparamagnetic Iron Oxide ◽

Superparamagnetic Iron Oxide Nanoparticles ◽

Oxide Nanoparticles ◽

Surface Charges ◽

Surface Modified

Background: Magnetic cell immobilization has been introduced as a novel, facile and highly efficient approach for cell separation. A stable attachment between bacterial cell wall with superparamagnetic iron oxide nanoparticles (SPIONs) would enable the microorganisms to be affected by an outer magnetic field. At high concentrations, SPIONs produce reactive oxygen species in cytoplasm, which induce apoptosis or necrosis in microorganisms. Choosing a proper surface coating could cover the defects and increase the efficiency. Methods: In this study, asparagine, APTES, lipo-amino acid and PEG surface modified SPIONs was synthesized by co-precipitation method and characterized by FTIR, TEM, VSM, XRD, DLS techniques. Then, their protective effects against four Gram-positive and Gram-negative bacterial strains including Enterococcus faecalis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were examined through microdilution broth and compared to naked SPION. Results: The evaluation of characterization results showed that functionalization of magnetic nanoparticles could change their MS value, size and surface charges. Also, the microbial analysis revealed that lipo-amino acid coated magnetic nanoparticles has the least adverse effect on microbial strain among tested SPIONs. Conclusion: This study showed lipo-amino acid could be considered as the most protective and even promotive surface coating, which is explained by its optimizing effect on cell penetration and negligible reductive effects on magnetic properties of SPIONs. lipo-amino acid coated magnetic nanoparticles could be used in microbial biotechnology and industrial microbiology.

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