Nearly monodispersed superparamagnetic maghemite nanoparticles (15-20nm) were prepared by a one-step thermal decomposition of iron(II) acetate in air at 400 degrees C. The presented synthetic route is simple, cost effective and allows to prepare the high-quality superparamagnetic particles in a large scale. The as-prepared particles were exploited for the development of magnetic nanocomposites with the possible applicability in medicine and biochemistry. For the purposes of the MRI diagnostics, the maghemite particles were simply dispersed in the bentonite matrix. The resulting nanocomposite represents very effective and cheap oral negative contrast agent for MRI of the gastrointestinal tract and reveals excellent contrast properties, fully comparable with those obtained for commercial contrast material. The results of the clinical research of this maghemite-bentonite contrast agent for imaging of the small bowel are discussed. For biochemical applications, the primary functionalization of the prepared maghemite nanoparticles with chitosan was performed. In this way, a highly efficient magnetic carrier for protein immobilization was obtained as demonstrated by conjugating thermostable raffinose-modified trypsin (RMT) using glutaraldehyde. The covalent conjugation resulted in a further increase in trypsin thermostability (T(50)=61 degrees C) and elimination of its autolysis. Consequently, the immobilization of RMT allowed fast in-solution digestion of proteins and their identification by MALDI-TOF mass spectrometry.
Magnetite (Fe3O4) nanoparticles with uniform sizes of 10, 20, and 31 nm were prepared by thermal decomposition of Fe(III) oleate or mandelate in a high-boiling point solvent (>320 °C). To render the particles with hydrophilic and antifouling properties, their surface was coated with a PEG-containing bisphosphonate anchoring group. The PEGylated particles were characterized by a range of physicochemical methods, including dynamic light scattering, transmission electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, and magnetization measurements. As the particle size increased from 10 to 31 nm, the amount of PEG coating decreased from 28.5 to 9 wt.%. The PEG formed a dense brush-like shell on the particle surface, which prevented particles from aggregating in water and PBS (pH 7.4) and maximized the circulation time in vivo. Magnetic resonance relaxometry confirmed that the PEG-modified Fe3O4 nanoparticles had high relaxivity, which increased with increasing particle size. In the in vivo experiments in a mouse model, the particles provided visible contrast enhancement in the magnetic resonance images. Almost 70% of administrated 20-nm magnetic nanoparticles still circulated in the blood stream after four hours; however, their retention in the tumor was rather low, which was likely due to the antifouling properties of PEG.
- MeSH
- Diphosphonates chemistry MeSH
- Magnetic Resonance Imaging MeSH
- Magnetite Nanoparticles chemistry ultrastructure MeSH
- Mice, Inbred C57BL MeSH
- Mice MeSH
- Polyethylene Glycols chemistry MeSH
- Tissue Distribution MeSH
- Microscopy, Electron, Transmission MeSH
- Particle Size MeSH
- Ferric Compounds MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Autori sa v práci zaoberaiú základnvmi parametrami zobrazovacích radiodiagnostických metód (ultrasonografia, počítačová tomografia, i, magnetická rezonancia) a porovnávajú ich hodnovernosť s výsledkami, ktoré získava patológ pitvou (autopsiou) alebo biopsiou chorobne zmenených ľudských tkanív a orgánov s možným využitím histochemických metód na dôkaz enzýmov, lipidov, sacharidov s osobitným diagnostickým významom imunohistochémie. Transmisná a rastrovacia elektrónová mikroskopia V diagnostickej praxi posúva možnosti morfologického skúmania na subcelulárnu až á úroveň. Autori poukazujú kriticky na možné problémy, ktoré môžu neinvazívne klinické zobrazovacie metódy a morfologické autoptické alebo bioptické vyšetrenia sprevádzať. Dochádzajú k záveru, že najbližšie k realite a hodnovernosti získaných výsledkov vedie vzájomná symbióza a súčasná kombinácia obidvoch prístupov.
In this study the authors deal with general parameters of imaging radiodiagnostic methods (ultrasonography, computerized tomography and magnetic resonance) and they compare their reliability with the results gained at autopsy or biopsy of pathologically changed human tissues and organs with possible applicability of histochemical methods for the proof of enzymes, lipids and sugars, with special diagnostic importance of immunohistochemistry. Scanning and transmission electron microscopy in diagnostic practice shifts the possibiUties of morphological research to subcellular and even to molecular level. The authors show the possible problems which the non inva¬ sivé clinical imaging methods and morphological examinations can accompany. They come to the conclusion that the mutual symbiosis and combination of both approaches provide the most real and trustful results.
Maghemite (gamma-Fe2O3) nanoparticles were obtained by the coprecipitation of Fe(II) and Fe (III) salts with ammonium hydroxide followed by oxidation with sodium hypochlorite. Solution radical polymerization of N,N-dimethylacrylamide(DMAAm) in the presence of maghemite nanoparticles yielded poly(N,N-dimethylacrylamide)(PDMAAm)-coated maghemite nanoparticles. The presence of PDMAAm on the maghemite particle surface was confirmed by elemental analysis and ATR FTIR spectroscopy. Other methods of nanoparticle characterization involved scanning and transmission electron microscopy, atomic adsorption spectroscopy (AAS), and dynamic light scattering (DLS). The conversion of DMAAm during polymerization and the molecular weight of PDMAAmbound to maghemite were determined by using gas and size-exclusion chromatography, respectively. The effect of ionic 4,4'-azobis(4-cyanovaleric acid) (ACVA) initiator on nanoparticle morphology was elucidated. The nanoparticles exhibited long-term colloidal stability in water or physiological buffer. Rat and human bone marrow mesenchymal stem cells (MSCs) were labeled with uncoated and PDMAAm-coated maghemite nanoparticles and with Endorem as a control. Uptake of the nanoparticles was evaluated by Prussian Blue staining, transmission electron microscopy, T(2)-MR relaxometry, and iron content analysis. Significant differences in labeling efficiency were found for human and rat cells. PDMAAm-modified nanoparticles demonstrated a higher efficiency of intracellular uptake into human cells in comparison with that of dextran-modified (Endorem) and unmodified nanoparticles. In gelatin, even a small number of labeled cells changed the contrast in MR images. PDMAAmcoatednanoparticles provided the highest T(2) relaxivity of all the investigated particles. In vivo MR imaging ofPDMAAm-modified iron oxide-labeled rMSCs implanted in a rat brain confirmed their better resolution compared with Endorem-labeled cells.
- MeSH
- Acrylamides chemistry MeSH
- Staining and Labeling methods MeSH
- Financing, Organized MeSH
- Rats MeSH
- Humans MeSH
- Magnetic Resonance Spectroscopy MeSH
- Magnetic Resonance Imaging MeSH
- Mesenchymal Stem Cells cytology metabolism ultrastructure MeSH
- Nanoparticles chemistry MeSH
- Scattering, Radiation MeSH
- Spectroscopy, Fourier Transform Infrared MeSH
- Microscopy, Electron, Transmission MeSH
- Cell Survival MeSH
- Gelatin metabolism MeSH
- Ferric Compounds chemical synthesis chemistry metabolism MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Humans MeSH
- Animals MeSH
INTRODUCTION: Magnetic resonance (MR) imaging is suitable for noninvasive long-term tracking. We labeled human induced pluripotent stem cell-derived neural precursors (iPSC-NPs) with two types of iron-based nanoparticles, silica-coated cobalt zinc ferrite nanoparticles (CZF) and poly-l-lysine-coated iron oxide superparamagnetic nanoparticles (PLL-coated γ-Fe2O3) and studied their effect on proliferation and neuronal differentiation. MATERIALS AND METHODS: We investigated the effect of these two contrast agents on neural precursor cell proliferation and differentiation capability. We further defined the intracellular localization and labeling efficiency and analyzed labeled cells by MR. RESULTS: Cell proliferation was not affected by PLL-coated γ-Fe2O3 but was slowed down in cells labeled with CZF. Labeling efficiency, iron content and relaxation rates measured by MR were lower in cells labeled with CZF when compared to PLL-coated γ-Fe2O3. Cytoplasmic localization of both types of nanoparticles was confirmed by transmission electron microscopy. Flow cytometry and immunocytochemical analysis of specific markers expressed during neuronal differentiation did not show any significant differences between unlabeled cells or cells labeled with both magnetic nanoparticles. CONCLUSION: Our results show that cells labeled with PLL-coated γ-Fe2O3 are suitable for MR detection, did not affect the differentiation potential of iPSC-NPs and are suitable for in vivo cell therapies in experimental models of central nervous system disorders.
- MeSH
- Cell Differentiation * MeSH
- Fibroblasts cytology MeSH
- Immunoenzyme Techniques MeSH
- Induced Pluripotent Stem Cells cytology MeSH
- Contrast Media chemistry MeSH
- Cells, Cultured MeSH
- Real-Time Polymerase Chain Reaction MeSH
- Humans MeSH
- Lysine chemistry MeSH
- Magnetic Resonance Imaging methods MeSH
- Magnetite Nanoparticles chemistry MeSH
- Neurons cytology MeSH
- Lung cytology MeSH
- Fetus cytology MeSH
- Cell Proliferation MeSH
- Flow Cytometry MeSH
- Microscopy, Electron, Transmission MeSH
- Check Tag
- Humans MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
Nanomaterials are currently the subject of intense research due to their wide variety of potential applications in the biomedical, optical and electronic fields. We prepared and tested cobalt zinc ferrite nanoparticles (Co0.5Zn0.5Fe2O4+γ [CZF-NPs]) encapsulated by amorphous silica in order to find a safe contrast agent and magnetic label for tracking transplanted cells within an organism using magnetic resonance imaging (MRI). Rat mesenchymal stem cells (rMSCs) were labeled for 48 h with a low, medium or high dose of CZF-NPs (0.05; 0.11 or 0.55 mM); silica NPs (Si-NPs; 0.11 mM) served as a positive control. The internalization of NPs into cells was verified by transmission electron microscopy. Biological effects were analyzed at the end of exposure and after an additional 72 h of cell growth without NPs. Compared to untreated cells, Annexin V/Propidium Iodide labeling revealed no significant cytotoxicity for any group of treated cells and only a high dose of CZF-NPs slowed down cell proliferation and induced DNA damage, manifested as a significant increase of DNA-strand breaks and oxidized DNA bases. This was accompanied by high concentrations of 15-F2t-isoprostane and carbonyl groups, demonstrating oxidative injury to lipids and proteins, respectively. No harmful effects were detected in cells exposed to the low dose of CZF-NPs. Nevertheless, the labeled cells still exhibited an adequate relaxation rate for MRI in repeated experiments and ICP-MS confirmed sufficient magnetic label concentrations inside the cells. The results suggest that the silica-coated CZF-NPs, when applied at a non-toxic dose, represent a promising contrast agent for cell labeling.
- MeSH
- Staining and Labeling MeSH
- Cell Culture Techniques MeSH
- Isoprostanes metabolism MeSH
- Protein Carbonylation drug effects MeSH
- Cobalt chemistry toxicity MeSH
- Contrast Media chemistry toxicity MeSH
- Rats MeSH
- Cells, Cultured MeSH
- Magnetic Resonance Imaging MeSH
- Lipid Metabolism drug effects MeSH
- Mesenchymal Stem Cells drug effects metabolism ultrastructure MeSH
- Nanoparticles chemistry toxicity MeSH
- Silicon Dioxide chemistry toxicity MeSH
- DNA Damage * MeSH
- Surface Properties MeSH
- Cell Proliferation drug effects MeSH
- Zinc Compounds chemistry toxicity MeSH
- Microscopy, Electron, Transmission MeSH
- Cell Survival drug effects MeSH
- Dose-Response Relationship, Drug MeSH
- Ferric Compounds chemistry toxicity MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Iron oxide nanoparticles obtained by the coprecipitation of Fe(II) and Fe(III) salts and oxidation were coated with a novel poly(vinyl acetate-co-5-tert-(butylperoxy)-5-methylhex-1-en-3-yne-co-butyl acrylate-co-maleic anhydride) (PVBM) oligomer to ensure colloidal stability. The magnetic nanoparticles were thoroughly characterized by a range of physico-chemical methods, which proved the presence of the coating on the particles. Experiments with rat mesenchymal stem cells (rMSCs) confirmed that PVBM-coated gamma-Fe2O3 nanoparticles were not cytotoxic and that the average efficiency of stem cell labeling was good and comparable to that obtained with commercial agents. The cells labeled with PVBM-coated gamma-Fe2O3 nanoparticles displayed excellent contrast on magnetic resonance (MR) images. Such particles are thus promising for in vivo MR imaging of transplanted cells. Moreover, PVBM offers the possibility of additional modification by grafting compounds that reduce non-specific protein adsorption.
- MeSH
- Staining and Labeling methods MeSH
- Femur cytology MeSH
- Metal Nanoparticles chemistry MeSH
- Rats MeSH
- Magnetic Resonance Spectroscopy MeSH
- Magnetic Resonance Imaging MeSH
- Magnetics MeSH
- Mesenchymal Stem Cells chemistry MeSH
- Molecular Structure MeSH
- Surface Properties MeSH
- Microscopy, Electron, Transmission MeSH
- Cell Survival MeSH
- Ferric Compounds chemistry MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
New surface-modified iron oxide nanoparticles were developed by precipitation of Fe(II) and Fe(III) salts with ammonium hydroxide and oxidation of the resulting magnetite with sodium hypochlorite, followed by the addition of poly( L-lysine) (PLL) solution. PLL of several molecular weights ranging from 146 ( L-lysine) to 579 000 was tested as a coating to boost the intracellular uptake of the nanoparticles. The nanoparticles were characterized by TEM, dynamic light scattering, FTIR, and ultrasonic spectrometry. TEM revealed that the particles were ca. 6 nm in diameter, while FTIR showed that their surfaces were well-coated with PLL. The interaction of PLL-modified iron oxide nanoparticles with DMEM culture medium was verified by UV-vis spectroscopy. Rat bone marrow stromal cells (rMSCs) and human mesenchymal stem cells (hMSC) were labeled with PLL-modified iron oxide nanoparticles or with Endorem (control). Optical microscopy and TEM confirmed the presence of PLL-modified iron oxide nanoparticles inside the cells. Cellular uptake was very high (more than 92%) for PLL-modified nanoparticles that were coated with PLL (molecular weight 388 00) at a concentration of 0.02 mg PLL per milliliter of colloid. The cellular uptake of PLL-modified iron oxide was facilitated by its interaction with the negatively charged cell surface and subsequent endosomolytic uptake. The relaxivity of rMSCs labeled with PLL-modified iron oxide and the amount of iron in the cells were determined. PLL-modified iron oxide-labeled rMSCs were imaged in vitro and in vivo after intracerebral grafting into the contralateral hemisphere of the adult rat brain. The implanted cells were visible on magnetic resonance (MR) images as a hypointense area at the injection site and in the lesion. In comparison with Endorem, nanoparticles modified with PLL of an optimum molecular weight demonstrated a higher efficiency of intracellular uptake by MSC cells.
- MeSH
- Adsorption MeSH
- Chemical Phenomena MeSH
- Endocytosis drug effects MeSH
- Financing, Organized MeSH
- Chemistry, Physical MeSH
- Rats MeSH
- Culture Media MeSH
- Cells, Cultured MeSH
- Humans MeSH
- Lysine chemistry MeSH
- Magnetic Resonance Imaging MeSH
- Magnetics MeSH
- Mesenchymal Stem Cells drug effects ultrastructure MeSH
- Microscopy, Electron, Scanning MeSH
- Molecular Weight MeSH
- Nanoparticles MeSH
- Ferrosoferric Oxide MeSH
- Oxides chemistry MeSH
- Polylysine chemistry MeSH
- Proteins MeSH
- Spectroscopy, Fourier Transform Infrared MeSH
- Microscopy, Electron, Transmission MeSH
- Stem Cell Transplantation MeSH
- Ultrasonics MeSH
- Particle Size MeSH
- Ferric Compounds chemistry MeSH
- Iron chemistry MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Humans MeSH
- Animals MeSH
Sodium hyaluronate (HA) was associated with dopamine (DPA) and introduced as a coating for maghemite (γ-Fe(2)O(3)) nanoparticles obtained by the coprecipitation of iron(II) and iron(III) chlorides and oxidation with sodium hypochlorite. The effects of the DPA anchorage of HA on the γ-Fe(2)O(3) surface on the physicochemical properties of the resulting colloids were investigated. Nanoparticles coated at three different DPA-HA/γ-Fe(2)O(3) and DPA/HA ratios were chosen for experiments with rat bone marrow mesenchymal stem cells and human chondrocytes. The nanoparticles were internalized into rat bone marrow mesenchymal stem cells via endocytosis as confirmed by Prussian Blue staining. The efficiency of mesenchymal stem cell labeling was analyzed. From among the investigated samples, efficient cell labeling was achieved by using DPA-HA-γ-Fe(2)O(3) nanoparticles with DPA-HA/γ-Fe(2)O(3) = 0.45 (weight/ weight) and DPA/HA = 0.038 (weight/weight) ratios. The particles were used as a contrast agent in magnetic resonance imaging for the labeling and visualization of cells.
- MeSH
- Coated Materials, Biocompatible chemistry MeSH
- Cell Differentiation MeSH
- Chondrocytes cytology MeSH
- Dopamine chemistry MeSH
- Endocytosis MeSH
- Ferrocyanides MeSH
- Contrast Media diagnostic use MeSH
- Rats MeSH
- Cells, Cultured MeSH
- Hyaluronic Acid chemistry MeSH
- Humans MeSH
- Magnetic Resonance Imaging MeSH
- Magnetite Nanoparticles chemistry diagnostic use ultrastructure MeSH
- Mesenchymal Stem Cells cytology drug effects MeSH
- Nanomedicine MeSH
- Microscopy, Electron, Transmission MeSH
- Particle Size MeSH
- Cell Survival MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
BACKGROUND: Nanoparticle-based systems are promising for the development of imaging and therapeutic agents. The main advantage of nanoparticles over traditional systems lies in the possibility of loading multiple functionalities onto a single molecule, which are useful for therapeutic and/or diagnostic purposes. These functionalities include targeting moieties which are able to recognize receptors overexpressed by specific cells and tissues. However, targeted delivery of nanoparticles requires an accurate system design. We present here a rationally designed, genetically engineered, and chemically modified protein-based nanoplatform for cell/tissue-specific targeting. METHODS: Our nanoparticle constructs were based on the heavy chain of the human protein ferritin (HFt), a highly symmetrical assembly of 24 subunits enclosing a hollow cavity. HFt-based nanoparticles were produced using both genetic engineering and chemical functionalization methods to impart several functionalities, ie, the α-melanocyte-stimulating hormone peptide as a melanoma-targeting moiety, stabilizing and HFt-masking polyethylene glycol molecules, rhodamine fluorophores, and magnetic resonance imaging agents. The constructs produced were extensively characterized by a number of physicochemical techniques, and assayed for selective melanoma-targeting in vitro and in vivo. RESULTS: Our HFt-based nanoparticle constructs functionalized with the α-melanocyte-stimulating hormone peptide moiety and polyethylene glycol molecules were specifically taken up by melanoma cells but not by other cancer cell types in vitro. Moreover, experiments in melanoma-bearing mice indicate that these constructs have an excellent tumor-targeting profile and a long circulation time in vivo. CONCLUSION: By masking human HFt with polyethylene glycol and targeting it with an α-melanocyte-stimulating hormone peptide, we developed an HFt-based melanoma-targeting nanoplatform for application in melanoma diagnosis and treatment. These results could be of general interest, because the same strategy can be exploited to develop ad hoc nanoplatforms for specific delivery towards any cell/tissue type for which a suitable targeting moiety is available.
- MeSH
- alpha-MSH chemistry diagnostic use MeSH
- Apoferritins chemistry MeSH
- HT29 Cells MeSH
- Fluorescent Dyes chemistry diagnostic use MeSH
- Microscopy, Confocal MeSH
- Drug Delivery Systems MeSH
- Humans MeSH
- Magnetic Resonance Imaging MeSH
- Magnetite Nanoparticles chemistry diagnostic use ultrastructure MeSH
- Melanoma, Experimental diagnosis MeSH
- Mice, Inbred C57BL MeSH
- Mice MeSH
- Nanomedicine MeSH
- Nanotechnology MeSH
- Polyethylene Glycols chemistry MeSH
- Recombinant Proteins chemistry MeSH
- Protein Stability MeSH
- Microscopy, Electron, Transmission MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Male MeSH
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
