Magnetic resonance imaging of glioma with novel APTS-coated superparamagnetic iron oxide nanoparticles

Pharmacokinetics of magnetic iron oxide nanoparticles for medical applications

Magnetic iron oxide nanoparticles (MNPs) have been under intense investigation for at least the last five decades as they show enormous potential for many biomedical applications, such as biomolecule separation, MRI imaging and hyperthermia. Moreover, a large area of research on these nanostructures is concerned with their use as carriers of drugs, nucleic acids, peptides and other biologically active compounds, often leading to the development of targeted therapies. The uniqueness of MNPs is due to their nanometric size and unique magnetic properties. In addition, iron ions, which, along with oxygen, are a part of the MNPs, belong to the trace elements in the body. Therefore, after digesting MNPs in lysosomes, iron ions are incorporated into the natural circulation of this element in the body, which reduces the risk of excessive storage of nanoparticles. Still, one of the key issues for the therapeutic applications of magnetic nanoparticles is their pharmacokinetics which is reflected in the circulation time of MNPs in the bloodstream. These characteristics depend on many factors, such as the size and charge of MNPs, the nature of the polymers and any molecules attached to their surface, and other. Since the pharmacokinetics depends on the resultant of the physicochemical properties of nanoparticles, research should be carried out individually for all the nanostructures designed. Almost every year there are new reports on the results of studies on the pharmacokinetics of specific magnetic nanoparticles, thus it is very important to follow the achievements on this matter. This paper reviews the latest findings in this field. The mechanism of action of the mononuclear phagocytic system and the half-lives of a wide range of nanostructures are presented. Moreover, factors affecting clearance such as hydrodynamic and core size, core morphology and coatings molecules, surface charge and technical aspects have been described.

A short review of graphene in the microbial electrosynthesis of biochemicals from carbon dioxide

Microbial electrosynthesis (MES) is a potential energy transformation technology for the reduction of the greenhouse gas carbon oxide (CO2) into commercial chemicals.

Construction of nanomaterials as contrast agents or probes for glioma imaging

Malignant glioma remains incurable largely due to the aggressive and infiltrative nature, as well as the existence of blood-brain-barrier (BBB). Precise diagnosis of glioma, which aims to accurately delineate the tumor boundary for guiding surgical resection and provide reliable feedback of the therapeutic outcomes, is the critical step for successful treatment. Numerous imaging modalities have been developed for the efficient diagnosis of tumors from structural or functional aspects. However, the presence of BBB largely hampers the entrance of contrast agents (Cas) or probes into the brain, rendering the imaging performance highly compromised. The development of nanomaterials provides promising strategies for constructing nano-sized Cas or probes for accurate imaging of glioma owing to the BBB crossing ability and other unique advantages of nanomaterials, such as high loading capacity and stimuli-responsive properties. In this review, the recent progress of nanomaterials applied in single modal imaging modality and multimodal imaging for a comprehensive diagnosis is thoroughly summarized. Finally, the prospects and challenges are offered with the hope for its better development.

Magnetite nanoparticle anchored graphene cathode enhances microbial electrosynthesis of polyhydroxybutyrate by Rhodopseudomonas palustris TIE-1

Microbial electrosynthesis (MES) is an emerging technology that can convert carbon dioxide (CO₂) into value-added organic carbon compounds using electrons supplied from a cathode. However, MES is affected by low product formation due to limited extracellular electron uptake by microbes. Herein, a novel cathode was developed from chemically synthesized magnetite nanoparticles and reduced graphene oxide nanocomposite (rGO-MNPs). This nanocomposite was electrochemically deposited on carbon felt (CF/rGO-MNPs), and the modified material was used as a cathode for MES production. The bioplastic, polyhydroxybutyrate (PHB) produced by Rhodopseudomonas palustris TIE-1 (TIE-1), was measured from reactors with modified and unmodified cathodes. Results demonstrate that the magnetite nanoparticle anchored graphene cathode (CF/rGO-MNPs) exhibited higher PHB production (91.31 ± 0.9 mg l^-1). This is ∼4.2 times higher than unmodified carbon felt (CF), and 20 times higher than previously reported using graphite. This modified cathode enhanced electron uptake to -11.7 ± 0.1 μA cm^-2, ∼5 times higher than CF cathode (-2.3 ± 0.08 μA cm^-2). The faradaic efficiency of the modified cathode was ∼2 times higher than the unmodified cathode. Electrochemical analysis and scanning electron microscopy suggest that rGO-MNPs facilitated electron uptake and improved PHB production by TIE-1. Overall, the nanocomposite (rGO-MNPs) cathode modification enhances MES efficiency.

Surface Modification of Magnetic Iron Oxide Nanoparticles

Functionalized iron oxide nanoparticles (IONPs) are of great interest due to wide range applications, especially in nanomedicine. However, they face challenges preventing their further applications such as rapid agglomeration, oxidation, etc. Appropriate surface modification of IONPs can conquer these barriers with improved physicochemical properties. This review summarizes recent advances in the surface modification of IONPs with small organic molecules, polymers and inorganic materials. The preparation methods, mechanisms and applications of surface-modified IONPs with different materials are discussed. Finally, the technical barriers of IONPs and their limitations in practical applications are pointed out, and the development trends and prospects are discussed.

Preparation and characterization of superparamagnetic iron oxide nanoparticles for magnetically guided drug delivery

Iron oxide nanoparticles have unique magnetic properties and therefore readily respond to applied magnetic fields. Moreover, their surfaces can be used to attach active molecules via various covalent or noncovalent interactions. Thus, they can be used as drug carriers for magnetically controlled delivery to specific biological sites of interest. In the present study, we have synthesized aqueous dispersed samples of citric acid-capped iron oxide nanoparticles, and the anticancer drug doxorubicin was then linked with these superparamagnetic iron oxide nanoparticles via a simple noncovalent interaction. Our results show that the conjugated drug releases from the nanoparticles in a sustained manner. The cellular uptake of these nanoparticles was found to be substantial, although it can be further enhanced using magnetic guidance. These nanoparticles (drug free) were found to be nontoxic to cells; however, upon drug conjugation, drug-induced toxicity was observed, owing to the slow release of drug from the nanoparticles.

Facile Synthesis of Folic Acid-Modified Iron Oxide Nanoparticles for Targeted MR Imaging in Pulmonary Tumor Xenografts

PURPOSE

The purpose of this study was to develop folic acid (FA)-modified iron oxide (Fe3O4) nanoparticles (NPs) for targeted magnetic resonance imaging (MRI) of H460 lung carcinoma cells.

PROCEDURES

Water-dispersible Fe3O4 NPs synthesized via a mild reduction method were conjugated with FA to generate FA-targeted Fe3O4 NPs. The specificity of FA-targeted Fe3O4 NPs to bind FA receptor was investigated in vitro by cellular uptake and cell MRI and in vivo by MRI of H460 tumors.

RESULTS

The formed NPs displayed good biocompatibility and ultrahigh r 2 relaxivity (440.01/mM/s). The targeting effect of the NPs to H460 cells was confirmed by in vitro cellular uptake and cell MRI. H460 tumors showed a significant reduction in T2 signal intensity at 0.85 h, which then recovered and returned to control at 2.35 h.

CONCLUSIONS

The results indicate that the prepared FA-targeted Fe3O4 NPs have potential to be used as T2 negative contrast agents in targeted MRI.

In-Vitro Assessment of Magnetic Dextran-Spermine Nanoparticles for Capecitabine Delivery to Cancerous Cells

Cationic polymeric nanoparticles have great potential for developing drug delivery systems with limited side effects for tumor medication. The goal of this research is investigation of cationic dextran-spermine polymer (DS) efficacy for improvement of hydrophilic drug delivery to negatively charged cancerous cells. Capecitabine (as a hydrophilic antineoplastic drug) was loaded into the magnetic dextran-spermine nanoparticles (DS-NPs) via ionic gelation. Design of experiments was applied to specify how the significant factors affect size, surface charge and capecitabine entrapment efficiency of the DS-NPs. Physicochemical properties, in-vitro release profile and cellular studies of the optimized DS-NPs were evaluated. The experimental results indicated that DS-NPs with favorable properties can be achieved at an optimized condition of 2 mg/mL DS and 0.75 mg/mL tri-polyphosphate (TPP) concentrations, TPP addition rate of 35 mL/min, pH 3 of DS solution and super paramagnetic iron oxide nanoparticles (SPION)/DS mass ratio of 0.5. The entrapment efficiency of capecitabine was 26.1% at optimum condition and drug release at neutral pH after 24 h and acidic pH within 3 h was 56 and 98%, respectively. The cytotoxicity assessment exhibited that capecitabine loaded DS-NPs was more toxic than corresponding free drug as control. Significant cellular uptake of capecitabine loaded DS-NPs by U87MG glioblastoma cells were proved by Prussian blue staining and TEM, qualitatively. DS-NPs are suitable candidates for delivery of the hydrophilic drugs in cancer treatment and due to positive charge of the dextran-spermine, the uptake of the hydrophilic drugs by the cancerous cells was improved.

Cytotoxicity and oxidative stress responses of silica-coated iron oxide nanoparticles in CHSE-214 cells

The present study aimed at investigating cytotoxicity and oxidative stress induced by silica-coated iron oxide nanoparticles functionalized with dithiocarbamate (Fe₃O₄ NPs) in Chinook salmon cells (CHSE-214) derived from Oncorhynchus tshawytscha embryos. A significant reduction in cell viability was evident in response to Fe₃O₄ NPs as revealed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay after 24 h of exposure. Out of the tested concentrations (10, 20, and 30 μg/ml), the highest concentration has shown significant decrease in the viability of cells after 24 h of exposure. Alterations in the morphology of CHSE-214 cells was also evident at 10 μg/ml concentration of Fe₃O₄ NPs after 24 h. Fe₃O₄ NPs elicited a significant dose-dependent reduction in total glutathione content (TGSH), catalase (CAT), glutathione reductase (GR) with a concomitant increase in lipid peroxidation (LPO), and protein carbonyl (PC) at highest concentration (30 μg/ml) after 24 h of exposure. In conclusion, our data demonstrated that Fe₃O₄ NPs have potential to induce cytotoxicity in CHSE-214 cells, which is likely to be mediated through reactive oxygen species generation and oxidative stress.

Conjugation Magnetic PAEEP-PLLA Nanoparticles with Lactoferrin as a Specific Targeting MRI Contrast Agent for Detection of Brain Glioma in Rats

The diagnosis of malignant brain gliomas is largely based on magnetic resonance imaging (MRI) with contrast agents. In recent years, nano-sized contrast agents have been developed for improved MRI diagnosis. In this study, oleylamine-coated Fe3O4 magnetic nanoparticles (OAM-MNPs) were synthesized with thermal decomposition method and encapsulated in novel amphiphilic poly(aminoethyl ethylene phosphate)/poly(L-lactide) (PAEEP-PLLA) copolymer nanoparticles. The OAM-MNP-loaded PAEEP-PLLA nanoparticles (M-PAEEP-PLLA-NPs) were further conjugated with lactoferrin (Lf) for glioma tumor targeting. The Lf-conjugated M-PAEEP-PLLA-NPs (Lf-M-PAEEP-PLLA-NPs) were characterized by photon correlation spectroscopy (PCS), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), thermo-gravimetric analysis (TGA), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). The average size of OAM-MNPs, M-PAEEP-PLLA-NPs, and Lf-M-PAEEP-PLLA-NPs were 8.6 ± 0.3, 165.7 ± 0.6, and 218.2 ± 0.4 nm, with polydispersity index (PDI) of 0.185 ± 0.023, 0.192 ± 0.021, and 0.224 ± 0.036, respectively. TEM imaging showed that OAM-MNPs were monodisperse and encapsulated in Lf-M-PAEEP-PLLA-NPs. TGA analysis showed that the content of iron oxide nanoparticles was 92.8 % in OAM-MNPs and 45.2 % in Lf-M-PAEEP-PLLA-NPs. VSM results indicated that both OAM-MNPs and Lf-M-PAEEP-PLLA-NPs were superparamagnetic, and the saturated magnetic intensity were 77.1 and 74.8 emu/g Fe. Lf-M-PAEEP-PLLA-NPs exhibited good biocompatibility in cytotoxicity assay. The high cellular uptake of Lf-M-PAEEP-PLLA-NPs in C6 cells indicated that Lf provided effective targeting for the brain tumor cells. The T 2 relaxation rate (r 2) of M-PAEEP-PLLA-NPs and Lf-M-PAEEP-PLLA-NPs were calculated to be 167.2 and 151.3 mM(-1) s(-1). In MRI on Wistar rat-bearing glioma tumor, significant contrast enhancement could clearly appear at 4 h after injection and last 48 h. Prussian blue staining of the section clearly showed the retention of Lf-M-PAEEP-PLLA-NPs in tumor tissues. The results from the in vitro and in vivo MRI indicated that Lf-M-PAEEP-PLLA-NPs possessed strong, long-lasting, tumor targeting, and enhanced tumor MRI contrast ability. Lf-M-PAEEP-PLLA-NPs represent a promising nano-sized MRI contrast agent for brain glioma targeting MRI.

Application of iron oxide nanoparticles in glioma imaging and therapy: from bench to bedside

Gliomas are the most common primary brain tumors and have a very dismal prognosis. However, recent advancements in nanomedicine and nanotechnology provide opportunities for personalized treatment regimens to improve the poor prognosis of patients suffering from glioma. This comprehensive review starts with an outline of the current status facing glioma. It then provides an overview of the state-of-the-art applications of iron oxide nanoparticles (IONPs) to glioma diagnostics and therapeutics, including MR contrast enhancement, drug delivery, cell labeling and tracking, magnetic hyperthermia treatment and magnetic particle imaging. It also addresses current challenges associated with the biological barriers and IONP design with an emphasis on recent advances and innovative approaches for glioma targeting strategies. Opportunities for future development are highlighted.

Recombinant interleukin-1 receptor antagonist conjugated to superparamagnetic iron oxide nanoparticles for theranostic targeting of experimental glioblastoma

Cerebral edema commonly accompanies brain tumors and contributes to neurologic symptoms. The role of the interleukin-1 receptor antagonist conjugated to superparamagnetic iron oxide nanoparticles (SPION-IL-1Ra) was assessed to analyze its anti-edemal effect and its possible application as a negative contrast enhancing agent for magnetic resonance imaging (MRI). Rats with intracranial C6 glioma were intravenously administered at various concentrations of IL-1Ra or SPION-IL-1Ra. Brain peritumoral edema following treatment with receptor antagonist was assessed with high-field MRI. IL-1Ra administered at later stages of tumor progression significantly reduced peritumoral edema (as measured by MRI) and prolonged two-fold the life span of comorbid animals in a dose-dependent manner in comparison to control and corticosteroid-treated animals (P < .001). Synthesized SPION-IL-1Ra conjugates had the properties of negative contrast agent with high coefficients of relaxation efficiency. In vitro studies of SPION-IL-1Ra nanoparticles demonstrated high intracellular incorporation and absence of toxic influence on C6 cells and lymphocyte viability and proliferation. Retention of the nanoparticles in the tumor resulted in enhanced hypotensive T2-weighted images of glioma, proving the application of the conjugates as negative magnetic resonance contrast agents. Moreover, nanoparticles reduced the peritumoral edema confirming the therapeutic potency of synthesized conjugates. SPION-IL-1Ra nanoparticles have an anti-edemal effect when administered through a clinically relevant route in animals with glioma. The SPION-IL-1Ra could be a candidate for theranostic approach in neuro-oncology both for diagnosis of brain tumors and management of peritumoral edema.

Facile synthesis of RGD peptide-modified iron oxide nanoparticles with ultrahigh relaxivity for targeted MR imaging of tumors

We report the facile synthesis of arginine-glycine-aspartic acid (RGD) peptide-targeted iron oxide (Fe3O4) nanoparticles (NPs) with ultrahigh relaxivity for in vivo tumor magnetic resonance (MR) imaging. In this study, stable polyethyleneimine (PEI)-coated Fe3O4 NPs were first prepared by a mild reduction route. The formed aminated Fe3O4 NPs with PEI coating were sequentially conjugated with fluorescein isothiocyanate (FI) and polyethylene glycol (PEG)-RGD segment, followed by acetylation of the remaining PEI surface amines. The thus-formed Fe3O4@PEI·NHAc-FI-PEG-RGD NPs were characterized via different techniques. We show that the multifunctional RGD-targeted Fe3O4 NPs with a mean size of 9.1 nm are water-dispersible, colloidally stable, and hemocompatible and cytocompatible in the given concentration range. With the displayed ultrahigh r2 relaxivity (550.04 mM(-1) s(-1)) and RGD-mediated targeting specificity to αvβ3 integrin-overexpressing cancer cells as confirmed by flow cytometry and confocal microscopy, the developed multifunctional Fe3O4@PEI·NHAc-FI-PEG-RGD NPs are able to be used as a highly efficient nanoprobe for targeted MR imaging of αvβ3 integrin-overexpressing cancer cells in vitro and the xenografted tumor model in vivo. Given the versatile PEI amine-enabled conjugation chemistry, the developed PEI-coated Fe3O4 NPs may be functionalized with other biological ligands or drugs for various biomedical applications, in particular, the diagnosis and therapy of different types of cancer.