Effect of surface charge of magnetite nanoparticles on their internalization into breast cancer and umbilical vein endothelial cells

Internalization of magnetite nanoparticles with diameter of approximately 40 nm into normal and cancer cells was examined by microscopic observation and flow cytometry. Magnetite nanoparticles were synthesized by hydrolysis in an aqueous solution containing ferrous chloride with organic amines as a base. It was demonstrated that the difference in surface charge of magnetite nanoparticles brought about the difference in uptake efficiency. The nanoparticles with positive charge showed higher internalization into human breast cancer cells than the nanoparticles with negative charge, while the degree of internalization of the positively- and negatively-charged nanoparticles into human umbilical vein endothelial cells (HUVEC) was almost the same.     

Characterization and analytical application of surface modified magnetic nanoparticles

Fe₃O₄ superparamagnetic nanoparticles with various functionalities were synthesized using a chemical co-precipitation method and used to demonstrate their analytical applications for protein separation of protein and metal ion extraction. The chemically inert silica layer coated with tetraethoxysilane (TEOS) protected the Fe₃O₄ core from a chemical attack and allowed the nanoparticles to be well dispersed in an aqueous solution. Particularly, the beads were resistant to an acidic solution with a pH ≥ 3. The amino (− NH₂) groups were covalently bonded to the silica coated Fe₃O₄, and then the carboxyl (− COOH) groups were functionalized to the nanoparticle surface through the reaction of − NH₂ and glutaric anhydride. The synthesized magnetic nanoparticles (MNP) were characterized using FT-IR, FE-TEM, XRD, and SQUID. The presence of functional groups on the nano beads was confirmed using molecular fluorescence spectrometry. For the presence of the amino (− NH₂) groups, FITC was tagged and monitored using an excitation laser with a wavelength of 473 nm and a fluorescence emission of 518 nm. Biotin was immobilized on the MNP and the fluorescent of FITC tagged on avidin was monitored to identify the carboxyl (− COOH) group.The proteins of Cytochrome C (12,000 Da), Rnase B (15,000 Da), and Myoglobin (17,000 Da) were separated using the MNP functionalized with the carboxyl (− COOH) group and identified using MALDI-TOF-MS. Amino benzyl EDTA (ethylenediaminetetraacetic acid) was immobilized on the MNP for metal–EDTA complexation to use the synthesized magnetic particles to extract metal ions for environmental and clinical application. Cu, Cd, Co, and Pb ions were extracted from ∼ 10 ng/mL solutions in the batch-type procedure and the extraction efficiency was > 90% at a pH of 4.     

Solid phase extraction-spectrophotometric determination of fluoride in water samples using magnetic iron oxide nanoparticles

A new, sensitive, fast and simple method using magnetic iron oxide nanoparticles (MIONs), as an adsorbent has been developed for extraction, preconcentration and determination of traces of fluoride ions. The determination method is based on the discoloration of Fe(III)-SCN complex with extracted fluoride ions which was subsequently monitored spectrophotometrically at λ_max = 458 nm. Various parameters affecting the adsorption of fluoride by the MIONs have been investigated, such as pH of the solution, type, volume and concentration of desorbing reagent, amount of adsorbent and interference effects. A linear response for the determination of fluoride was achieved in the concentration range of 0.040-1.250 μg mL⁻¹. The limit of detection (LOD) and limit of quantification (LOQ) for fluoride based on 3 times and 10 times the standard deviation of the blank (3S_b, 10S_b) were 0.015 and 0.042 μg mL⁻¹ (n = 20) for fluoride ion, respectively. A preconcentration factor of 50 was achieved in this method. The proposed procedure has been applied for determination of fluoride concentration in various water samples. The results obtained from this method were successfully compared with those provided by standard SPADNS method.     

磁性铁氧化物纳米粒子制备及其体内应用研究

磁性铁氧化物纳米粒子由于其生物相容性和低毒性而广泛的应用于生物医学领域。本文总结了近年来制备各种磁性铁氧化物纳米粒子的方法,比较了它们在粒径、结晶度以及制备条件等方面的优缺点,概括了对其进行表面修饰改性材料的种类,阐述近年来磁性铁氧化物纳米粒子在体内应用中药物运输、磁共振成像、磁热疗方面的进展,并指出当前应用中的主要方向和亟待解决的问题。     

Effects of surface modifications on the physicochemical properties of iron oxide nanoparticles and their performance as anticancer drug carriers

Surface of iron oxide nanoparticles were modified with citric acid (CA), chitosan (CS) and folic acid conjugated chitosan (FA-g-CS), respectively. Their physicochemical properties, doxorubicin loading capacity, drug release patterns and in vitro cytotoxicity were comparatively studied.     

Synthesis of magnetic nanoparticles and their application to bioassays

Magnetic nanoparticles have been attracting much interest as a labeling material in the fields of advanced biological and medical applications such as drug delivery, magnetic resonance imaging, and array-based assaying. In this review, synthesis of iron oxide magnetic nanoparticles via a reverse micelle system and modification of their surface by an organosilane agent are discussed. Furthermore, as a practical biological assay system, the magnetic detection of biomolecular interactions is demonstrated by using the combination of a patterned substrate modified with a self-assembled monolayer and the magnetic nanoparticles.     

Enhanced modulation of magnetic field on surface plasmon coupled emission (SPCE) by magnetic nanoparticles

This article demonstrates the enhancement of magnetic nanoparticles on magnetic field modulation of surface plasmon coupled emission (SPCE), and this method is designed as a biosensor to prove the feasibility of magnetic field modulated SPCE to be employed in the field of biosensing and biodetection.     

Electrochemical study of the effect of functionalized nickel nanoparticles on cellular uptake of leukemia cancer cells in vitro

In this study, we have fabricated the functionalized nickel nanoparticles and investigated their effects on cellular uptake of quercetin in leukemia K562 cancer cells by using electrochemical assay. The results indicate that nickel nanoparticles could efficiently enhance the quercetin uptake and increase the intracellular accumulation in cancer cells, implying the great potential of functionalized nickel nanoparticles in target cancer therapy.     

Enhanced modulation of magnetic field on surface plasmon coupled emission (SPCE) by magnetic nanoparticles

The obvious enhancement effect of magnetic nanoparticles (MNPs) introduced in Cr/Co/Cr/Au substrate on the pulsed magnetic field-modulated surface plasmon coupled emission (SPCE) was investigated, and the observed enhancement factor was 4 comparing with the magnetic field modulated SPCE without MNPs. This is the new observation for the magnetic field modulated SPCE, and this method was designed as a biosensor, which to our knowledge, is the first application of magnetic field-modulated SPCE in biosensing and detection field. This strategy is a universal approach to increase the fluorescence signal and helps to build the new SPCE based stimulus-response system.     

Cu immobilized on chitosan-modified iron oxide magnetic nanoparticles: Preparation,characterization and investigation of its anti-lung cancer effects

Chitosan is a linear polysaccharide and non-toxic bioactive polymer with a wide variety of applications due to its functional properties such as ease of modification, and biodegradability. In this study, a green protocol for supporting of Cu(II) on chitosan-encapsulated magnetic Fe₃O₄ nanoparticles is described. The morphological and physicochemical features of the material were determined using several advanced techniques like fourier transformed infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), inductively coupled plasma (ICP), vibrating sample magnetometer (VSM) and X-ray photoelectron spectroscopy (XPS). The average diameter of the NPs was approximately 15–25 nm. In addition, the Fe₃O_/CS/Cu(II) nanocomposite was engaged in biological assays like study of anti-oxidant properties by DPPH mediated free radical scavenging test using BHT as a reference molecule. Thereafter, on having a significant IC₅₀ value in radical scavenging assay, we extended the bio-application of the desired nanocomposite in anticancer study of lung well-differentiated bronchogenic adenocarcinoma, lung moderately differentiated adenocarcinoma, and lung poorly differentiated adenocarcinoma of human lung in-vitro conditions. In the cytotoxicity and anti-human lung studies, the nanocomposite was treated to lung cancer lung well-differentiated bronchogenic adenocarcinoma (HLC-1), lung moderately differentiated adenocarcinoma (LC-2/ad), and lung poorly differentiated adenocarcinoma (PC-14) cell line following MTT assay. The cell viability of malignant lung cell line reduced dose-dependently in the presence of Fe₃O_/CS/Cu(II) nanocomposite. The recent results suggest that Fe₃O_/CS/Cu(II) nanocomposite have a suitable anticancer activity against lung cell lines.     

Synthesis and electrocatalytic activity of haemin-functionalised iron(II,III) oxide nanoparticles

Haemin-functionalised magnetic iron(II, III) oxide (Fe₃O₄) nanoparticles (Fe₃O₄/haemin) were synthesised by changing the acidity of a solution of the two compounds. The nanoparticles were characterised by transmission electron microscopy, UV–vis absorption spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, measurement of magnetisation, and electrochemical techniques. The properties of both haemin and Fe₃O₄ were retained. Thus, Fe₃O₄/haemin nanoparticles exhibited pronounced electrocatalytic activity towards trichloroacetic acid (TCA) like haemin itself. Interestingly, electrocatalytic activity towards TCA was affected by detection temperature, which was controlled via electrically heated carbon paste electrodes. The maximal catalytic current was 5.8 times higher at 60 °C than at room temperature (25 °C). This proposed electrochemical sensor for TCA possessed a linear detection range of 5–80 μM and a detection limit of 0.3 μM at 60 °C.     

Green and one‐pot surface coating of iron oxide magnetic nanoparticles with natural amino acids and biocompatibility investigation

We report the synthesis of iron oxide magnetic nanoparticles (IONPs) coated with various natural amino acids (AAs) using a one‐pot reaction in an aqueous medium. Several AAs, which contained hydrophilic and hydrophobic groups, were selected to study their effects on size, morphology and toxicity of IONPs. Functionalized IONPs were characterized using X‐ray diffraction, differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared spectroscopy, and scanning and transmission electron microscopies. Furthermore, vibrating sample magnetometry analysis shows these nanoparticles have excellent magnetic properties. Cellular toxicity of IONPs was also investigated on HFF2 cell lines. The AA‐coated IONPs are non‐toxic and biocompatible. Natural AA‐coated IONPs show a potential for their development in in vitro and in vivo biomedical fields due to their non‐toxicity, good ζ‐potential and related small size and narrow size distribution.     

Synthesis and characterization of a new magnetic bromochromate hybrid nanomaterial with triethylamine surface modified iron oxide nanoparticles

We describe a novel method for the synthesis a new magnetic bromochromate hybrid nanomaterial, Fe3O4@SiO2@TEA@[CrO3Br], as a catalyst. The physical properties, morphology and magnetic investigations of magnetic bromochromate hybrid nanomaterials are identified by transmission electron microscopy （TEM）, scanning electron microscopy （SEM） and vibrating sample magnetometer （VSM） techniques. Fourier transform infrared （FT-IR）, elemental analysis, X-ray fluorescence （XRF）, X-ray diffraction （XRD） were also used for structural identification. The quantity of chromium is approximately 0.38%, which confirms to the immobilization amount of [CrO3Br]- and is equal to 0.007 mol/100 g.     

Catalytic conversions of chloroolefins over iron oxide nanoparticles 2. Isomerization of dichlorobutenes over iron oxide nanoparticles stabilized on the surface of ultradispersed poly(tetrafluoroethylene)

Nanosized iron oxides stabilized on the surface of ultradispersed poly(tetrafluoroethylene) (UPTFE) granules were synthesized by the thermal destruction of iron formate in boiling bed of UPTFE on the surface of heated mineral oil. The particle size of nanoparticles (∼6 nm) containing 5, 10, and 16 wt.% Fe depends weakly on the temperature of synthesis and iron to polymer ratio. The metal state is determined by the synthesis conditions. The nanoparticles synthesized at 280 °C consist mainly of the Fe₃O₄ and Fe₂O₃ phases. The samples obtained at 320 °C also contain iron(II) oxide. The catalytic properties of the obtained samples were tested in dichlorobutene isomerization. Unlike isomerization on the iron oxide nanoparticles supported on silica gel, reaction over the UPTFE supports proceeds without an induction period. The sample with 10 wt.% Fe containing magnetically ordered γ-Fe₂O₃ nanoparticles possesses the highest catalytic activity. Fast electron exchange between the iron ions in different oxidation states and high defectiveness of the nanoparticles contribute, most likely, to the catalytic activity. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1383–1390, June, 2005.     

Impact and mechanism of TiO2 nanoparticles on DNA synthesis in vitro

The impact of TiO₂ nanoparticles on DNA synthesis in vitro in the dark and the molecular mechanism of such impact were studied. The impact of TiO₂ nanoparticles on DNA synthesis was investigated by adding TiO₂ nanoparticles in different sizes and at various concentrations into the polymerase chain reaction (PCR) system. TiO₂ nanoparticles were premixed with the DNA polymerase, the primer or the template, respectively and then the supernatant and the precipitation of each mixture were added into the PCR system separately to observe the impact on DNA synthesis. Sequentially the interaction between TiO₂ nanoparticles and the DNA polymerase, the primer or the template was further analyzed by using UV-visible spectroscopy and polyacrylamide gel electrophoresis (PAGE). The results suggest that TiO₂ nanoparticles inhibit DNA synthesis in the PCR system in the dark more severely than microscale TiO₂ particles at the equivalent concentration and the inhibition effect of TiO₂ nanoparticles is concentration dependent. The molecular mechanism of such inhibition is that in the dark, TiO₂ nanoparticles interact with the DNA polymerase through physical adsorption while TiO₂ nanoparticles do with the primer or the template in a chemical adsorption manner. The disfunction levels of the bio-molecules under the impact of TiO₂ nanoparticles are in the following order: the primer > the template > the DNA polymerase. Supported by the National Natural Science Foundation of China (Grant Nos. 50572074 & 50673078), the Shanghai Key Fundamental Project (Grant No. 06JC14068) and the Innovation Program of Shanghai Municipal Education Commission (Grant No. 08ZZ21)     

苯并噻唑和铁氧化物纳米粒子修饰的磁性棒碳糊电极上肼的电催化氧化反应：同时检测肼和苯酚

开发了一种磁性Fe3O4纳米粒子和2-(3,4-二羟苯基)苯并噻唑(DPB)修饰的磁性棒碳糊电极(MBCPE)用于电化学检测肼.首先将DPB自组装在Fe3O4纳米粒子上,然后将此复合物吸附于设计的MBCPE上. MBCPE电极将磁性纳米粒子吸引到电极表面.所得新型电极具有高的导电性和大的有效比表面积,因而对肼的电催化氧化反应有非常大的电流响应.采用伏安法、扫描电镜、电化学阻抗谱、红外光谱和紫外-可见光谱对修饰电极进行了表征.采用伏安法研究了在磷酸盐缓冲溶液(pH=7.0)中MBCPE/Fe3O4NPs/DPB电极上肼的电化学行为.作为电化学传感器, MBCPE/Fe3O4NPs/DPB电极对肼氧化反应表现出极高的电催化活性.在DPB存在下,肼的氧化电势下降,但其催化电流增加.电催化电流与肼浓度在0.1–0.4和0.7–12.0μmol/L二个区间内表现出线性关系,检测限为18.0 nmol/L.另外,研究了MBCPE/Fe3O4NPs/DPB电极同时检测肼和苯酚的性能.伏安实验结果显示,苯酚的线性区域为100–470μmol/L,检测限为24.3μmol/L.采用此电极检测了水样品中的肼和苯酚.     

Synthesis,physico‐chemical and biological study of trialkylsiloxyalkyl amine coated iron oxide/oleic acid magnetic nanoparticles for the treatment of cancer

New original water‐soluble magnetic nanoparticles based on natural components, magnetite–oleic acid–biologically active silyl modified alkanolamine, were synthesized. Physico‐chemical characterization, i.e. magnetic properties, concentration of magnetite, size of iron oxide core, of the nanoparticles synthesized and the corresponding magnetic fluids obtained, was carried out. Magnetic fluids were screened for in vitro cytotoxicity concerning human fibrosarcoma (HT‐1080), mouse hepatoma (MG‐22A) monolayer tumour cell lines and normal mouse fibroblasts (NIH 3T3). They possess low or moderate cytotoxic effects, are non‐toxic, exhibit high NO‐induction ability and strongly change tumour cell morphology. Copyright © 2008 John Wiley & Sons, Ltd.     

Conducting and magnetic behaviors of monodispersed iron oxide/polypyrrole nanocomposites synthesized by in situ chemical oxidative polymerization

This study describes the preparation of nanocomposites fabricated from monodispersed iron oxide (Fe₃O₄) and polypyrrole (PPy) by in situ chemical oxidative polymerization. The monodispersed 4 nm Fe₃O₄ nanoparticles which served as cores were synthesized using the thermal decomposition of a mixture of Iron (III) acetylacetonate and oleic acid in the presence of high boiling point solvents. The resulting nanoparticles were further dispersed in an aqueous solution with anionic surfactant sodium bis(2‐ethylhexyl) sulfosuccinate to form micelle/Fe₃O₄ spherical templates that avoid the aggregation of Fe₃O₄ nanoparticles during the further preparation of the nanocomposites. The Fe₃O₄/PPy nanocomposites were then synthesized via in situ chemical oxidative polymerization on the surface of the spherical templates. Both field‐emission scanning electron microscopy (FESEM) and high‐resolution transmission electron microscopy (HRTEM) images indicate that the resulting Fe₃O₄ nanoparticles are close to spherical dots with a particle size of about 4 nm and a standard deviation of less than 5% (4 ± 0.2 nm). Structural and morphological analysis using FESEM and HRTEM showed that the fabricated Fe₃O₄/PPy nanocomposites are core (Fe₃O₄)‐shell (PPy) structures. Morphology of the nanocomposites shows a remarkable change from spherical to tube‐like structures as the content of monodispersed Fe₃O₄ nanoparticles increases from 9% up to 24 wt %. The conductivities of these Fe₃O₄/PPy nanocomposites are about six times higher than those of PPy without Fe₃O₄. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4647–4655, 2007     

Effect of chirality on conformation and cellular uptake of poly(S-(o-nitrobenzyl)-L,D-cysteine)polypeptides

A series of poly(S-(o-nitrobenzyl)-L,D-cysteine)polypeptides with different chirality was synthesized and their molecular structures,secondary conformations,drug release and biological properties were thoroughly investigated.The chirality of the polypeptides had effect on secondary conformations and the cellular uptake behavior of the related nanoparticles.     

In vitro macrophage uptake and in vivo biodistribution of long-circulation nanoparticles with poly(ethylene-glycol)-modified PLA (BAB type) triblock copolymer

The effect of the PEG-grafted degree in the range of 0–30% on the in vitro macrophage uptake and in vivo biodistribution of poly(ethylene glycol)–poly(lactic acid)–poly(ethylene glycol) (PELE) nanoparticles (NPs) were investigated in this paper. The prepared NPs were characterized in terms of size, zeta potential, hydrophilicity, poly(vinyl alcohol) (PVA) residual on nanoparticles surfaces as well as drug loading. The macrophage uptake and biodistribution including plasma clearance kinetics following intravenous administration in mice of the NPs labeled by 6-coumarin were evaluated. The results showed that, except for the particles size, the hydrophilicity, superficial charges and in vitro phagocytosis amount of NPs are dependent on the PEG content in the copolymers greatly. The higher of the PEG content, the more hydrophilicity and the nearer to neutral surface charge was observed. And the prolonged circulation half-life (t_1/2) of the PELE NPs in plasma was also strongly depended on the PEG content with the similar trend. In particular for PELE30 (containing 30% of PEG content) NPs, with the lowest phagocytosis uptake accompanied the highest hydrophilicity and approximately neutral charge, it had the longest half-life in vivo with almost 12-fold longer and accumulation in the reticuloendothelial system organs close to 1/2-fold lower than those of reference PLA. These results demonstrated that the PELE30 NPs with neutral charge and suitable size has a promising potential as a long-circulating oxygen carrier system with desirable biocompatibility and biofunctionality.