Cytotoxic effects and the mechanism of three types of magnetic nanoparticles on human hepatoma BEL-7402 cells

The evaluation of the toxicity of magnetic nanoparticles (MNPs) has attracted much attention in recent years. The current study aimed to investigate the cytotoxic effects of Fe3O4, oleic acid-coated Fe3O4 (OA-Fe3O4), and carbon-coated Fe (C-Fe) nanoparticles on human hepatoma BEL-7402 cells and the mechanisms. WST-1 assay demonstrated that the cytotoxicity of three types of MNPs was in a dose-dependent manner. G1 (Fe3O4 and OA-Fe3O4) phase and G2 (C-Fe) phase cell arrests and apoptosis induced by MNPs were detected by flow cytometry analysis. The increase in apoptosis was accompanied with the Bax over-expression, mitochondrial membrane potential decrease, and the release of cytochrome C from mitochondria into cytosol. Moreover, apoptosis was further confirmed by morphological and biochemical hallmarks, such as swollen mitochondria with lysing cristae and caspase-3 activation. Our results revealed that certain concentrations of the three types of MNPs affect BEL-7402 cells viability via cell arrest and inducing apoptosis, and the MNPs-induced apoptosis is mediated through the mitochondrial-dependent pathway. The influence potency of MNPs observed in all experiments would be: C-Fe > Fe3O4 > OA-Fe3O4

Preparation, properties and biomedical applications progress of 1D magnetic nanomaterials with iron

Abstract 1D magnetic nanomaterials with iron, with the special physical properties and biological behaviour, have been found to possess the great promising applications in many fields. In this review, the components, structure, physicochemical properties, biocompatibility and in vitro and in vivo biomedical functions of magnetic nanowires (MNWs), nanorods (MNRs) with iron are summarised, especially their anisotropy shape and magnetism result in their many applications in biodetections and medical treatment fields. The potential future functions of these 1D magnetic nanomaterials compared to magnetic nanoparticles also is discussed by highlighting the possibility of integration with other metal‐compositions or bio‐compositions and with existing biotechnology as well as by pointing out their specific properties. Current limitations in the property improvement and issues related with the outcome of the MNRs in the body are also summarised in order to address the remaining challenge for the extended biomedical functions of MNRs in the clinical application field

Futile Recanalization after Endovascular Therapy in Acute Ischemic Stroke

Early recanalization after endovascular treatment could improve the prognosis of acute ischemia stroke. Futile recanalization often occurred which was one of the main causes of failure. By now the mechanisms of futile recanalization were not clear. They are probably concerned with bad collateral circulation, subacute reocclusion, large hypoperfusion volumes, microvascular compromise, and impaired cerebral autoregulation. Previous research found that some of the image markers could be used as the accurate predictors for poor prognosis after successful treatment in order to identify the patients who were not suitable for recanalization and reduce some of the unnecessary cost. Predictors for futile recanalization mentioned in our article can be used for supplement to make decision for endovascular treatment

Biomimetic Mineralization of Magnetic Iron Oxide Nanoparticles Mediated by Bi-Functional Copolypeptides

Magnetite (Fe3O4) nanoparticles are widely used in multiple biomedical applications due to their magnetic properties depending on the size, shape and organization of the crystals. However, the crystal growth and morphology of Fe3O4 nanoparticles remain difficult to control without using organic solvent or a high temperature. Inspired by the natural biomineralization process, a 14-mer bi-functional copolypeptide, leveraging the affinity of binding Fe3O4 together with targeting ovarian cancer cell A2780, was used as a template in the biomimetic mineralization of magnetite. Alongside this, a ginger extract was applied as an antioxidant and a size-conditioning agent of Fe3O4 crystals. As a result of the cooperative effects of the peptide and the ginger extract, the size and dispersibility of Fe3O4 were controlled based on the interaction of the amino acid and the ginger extract. Our study also demonstrated that the obtained particles with superparamagnetism could selectively be taken up by A2780 cells. In summary, the Fe3O4-QY-G nanoparticles may have potential applications in targeting tumor therapy or angiography

Novel Bi-Functional 14-mer Peptides with Both Ovarian Carcinoma Cells Targeting and Magnetic Fe3O4 Nanoparticles Affinity

Fe3O4 magnetic nanoparticles (Fe3O4-MNPs) have attracted much interest for their potential medical applications due to their desirable magnetic properties. However, their potential cytotoxicity, high RES clearance in circulation, and nonspecific distribution in tissue might be the main obstacles in practice. In the present study, a novel bi-functional 14-mer peptide with both ovarian carcinoma cells targeting and magnetic Fe3O4 nanoparticles affinity was designed and synthesized, and then a facile and effective modification method was developed to bestow the Fe3O4-MNPs with tumor-targeting capability via modification, using the bi-functional peptides. First, on the basis of a tumor-targeting 7-mer peptide QQTNWSL (Q-L) and another Fe3O4-MNPs-targeting 7-mer peptide TVNFKLY (T-Y)—screened by phage-displayed peptide libraries—two bi-functional 14-mer peptides sequenced as LSWNTQQ-YLKFNVT (abbreviated as LQ-YT) and QQTNWSL-YLKFNVT (QL-YT) were synthesized through combining the Q-L peptide and T-Y peptide in predetermined configurations. Their specificity for bonding with A2780 tumor cells and affinity for Fe3O4-MNPs were verified. Then the bi-functional 14-mer peptides were applied to modify the Fe3O4-MNPs. Results showed that both bi-functional 14-mer peptides could be conjugated to the Fe3O4-MNPs surface with high affinity. Immunofluorescence and Prussian blue staining assays indicated that the LQ-YT-modified Fe3O4-MNPs could specifically bond to A2780 tumor cells. In addition to our findings suggesting that more β-turns and random coils are conducive to increasing polypeptide surface area for binding and exposing the target group and bonding sites on LQ-YT to external targets, we demonstrated that the bi-functional 14-mer peptide has affinity for Fe3O4-MNPs, and that Fe3O4-MNPs, which was modified with a 14-mer peptide, could be bestowed with a targeting affinity for ovarian carcinoma cells

Biphasic calcium phosphate macroporous scaffolds derived from oyster shells for bone tissue engineering

National Natural Science Foundation of China [90923042]; Research Fund for the Doctoral Program of Higher Education [20101106110042]; National Key Technologies R & D Program of China [2007BAD07B05]; Fujian Provincial Department of Ocean and Fisheries of CThe aim of this work was to fabricate a macroporous scaffold from oyster shell by using an innovative combination of techniques. Crassostrea angulata shell characterized by a natural microporous structure (2-10 mu m) was used as raw material. Firstly, plate-like nanocrystals of AB-type carbonated hydroxyapatite (HA) were produced by hydrothermal conversion of fine-milled oyster shell powders. Secondly, interconnected macroporous scaffolds were prepared with the polymer replication method. The obtained scaffolds presented a biphasic structure of hydroxyapatite/beta-tricalcium phosphate (HA/beta-TCP) with a porosity of 91.4 +/- 1.2%, and showed an excellent permeability due to the open macropores (200-500 mu m) and interconnected micropores (100-500 nm) in macropore walls. The synthetic scaffolds were found to be non-cytotoxic and displayed better biocompatibility than pure HA scaffolds when seeded with pre-osteoblasts cells (MC3T3-E1). Therefore, the macroporous scaffolds derived from oyster shells would offer promising alternatives for bone tissue engineering applications. (C) 2011 Elsevier B.V. All rights reserved

Synthesis of Macroporous Magnetic Fe3O4 Microparticles Via a Novel Organic Matter Assisted Open-Cell Hollow Sphere Assembly Method

Macroporous magnetic Fe3O4 microparticles, which might act as both drug carriers and magnetocaloric media, were expected to have broad application prospects on magnetocaloric-responsively controlled drug release systems. A kind of macroporous magnetic Fe3O4 microparticle was prepared by an organic matter assisted open-cell hollow sphere (hollow sphere with holes on shell) assembly method in this study. 1-vinyl-2-pyrrolidinone (NVP) and 2-acrylamido-2-methyl propane sulfonic acid (AMPS) were selected as the template and the binder, respectively. Ferrous ions were specifically bound to carbonyl groups on NVP and were then reduced by NaBH4. The reduced irons underwent heterogeneous nucleation and grain growth to form Fe0/Fe3O4 microspheres consisting of a lot of nano-Fe0 grains, and were then assembled into Fe0/Fe3O4 microparticles wrapped by AMPS. Results indicate that NVP binding with ferrous ions can promote a self-polymerization process and the formation of Fe0/Fe3O4 microspheres, while AMPS enwrapping around the resultant microspheres can facilitate their assembly into larger aggregates. As a result, macroporous Fe3O4 microparticles composed of several open-cell hollow Fe3O4 microspheres can be obtained under a Kirkendall-controlled oxidation. Moreover, these as-prepared macroporous Fe3O4 microparticles possess a narrow particle size distribution and exhibit ferromagnetism (Ms = 66.14 emu/g, Mr = 6.33 emu/g, and Hc = 105.32 Oe). Our work, described here, would open up a novel synthesis method to assemble macroporous magnetic Fe3O4 microparticles for potential application in magnetocaloric-responsively controlled drug release systems

Injectable Multicomponent Biomimetic Gel Composed of Inter-Crosslinked Dendrimeric and Mesoporous Silica Nanoparticles Exhibits Highly Tunable Elasticity and Dual Drug Release Capacity

There is a growing need for cartilage defect grafts that are structurally adaptable to possess multifaceted functions to promote bone regeneration, sustain medication efficacy, and preferably remain injectable but solidify quickly upon injection. In this work, we developed an injectable multicomponent biomimetic gel (MBG) by integrating polyamidoamine dendrimer G3 (G3), mesoporous silica nanoparticles (MSNs), and dendrimer-templated silver nanoparticles (G3-Ag) into a well-defined cross-linked network. MBGs composed of one particulate component (G3 alone), i.e., MBG-1, two particulate components (G3 and MSN-NH2), i.e., MBG-2, and three particulate components (G3, MSN-NH2, and G3-Ag), i.e., MBG-3, were prepared by inter-cross-linking dendrimeric and mesoporous silica nanoparticles with poly(ethylene glycol) diglycidyl ether (PEG-DGE, Mn = 2000 g/mol) via the facile amine-epoxy click reaction. The water-soluble antibiotic isoniazid was loaded to the cross-linked PEG network, whereas the hydrophobic antibiotic rifampicin was encapsulated into mesoporous MSNs. Our studies revealed that elasticity and mechanical strengths could be modulated and enhanced significantly with the inclusion of MSNs and silver nanoparticles. Isoniazid was released rapidly while rifampicin was released over an extended period of time. In addition, MBGs showed injectability, high swelling capacity, structural stability, and cytocompatibility. Taken together, MBGs have shown structural features that allow for the development of injectable gel grafts with the ability to promote cartilage defect repair and offer antibiotic medication benefits