Incorporation Of Iron Oxide Nanoparticles Research Articles

Fluorous-phase iron oxide nanoparticles as enhancers of acoustic droplet vaporization of perfluorocarbons with supra-physiologic boiling point

Perfluorocarbon emulsion nanodroplets containing iron oxide nanoparticles (IONPs) within their inner perfluorohexane (PFH) core were prepared to investigate potential use as an acoustically activatable ultrasound contrast agent, with the hypothesis that incorporation of IONPs into the fluorous phase of a liquid perfluorocarbon emulsion would potentiate acoustic vaporization. IONPs with an oleic acid (OA) hydrophobic coating were synthesized through chemical co-precipitation. To suspend IONP in PFH, OA was exchanged with perfluorononanoic acid (PFNA) via ligand exchange to yield fluorophilic PFNA-coated IONPs (PFNA-IONPs). Suspensions with various amounts of PFNA-IONPs (0–15% w/v) in PFH were emulsified in saline by sonication, using 5% (w/v) egg yolk phospholipid as an emulsifier. PFNA-IONPs were characterized with transmission electron microscopy (TEM), transmission electron cryomicroscopy (cryoTEM), and thermogravimetric analysis (TGA) with Fourier transform infrared spectroscopy (FTIR). IONP were between 5 and 10 nm in diameter as measured by electron microscopy, and hydrodynamic size of the PFH nanodroplets were 150 to 230 nm as measured by dynamic light scattering (DLS). Acoustic droplet vaporization of PFH nanodroplets (PFH-NDs) was induced using conversion pulses (100 cycle at 1.1 MHz and 50% duty cycle) provided by a focused ultrasound transducer, and formed microbubbles were imaged using a clinical ultrasound scanner. The acoustic pressure threshold needed for PFH-NDs vaporization decreased with increasing temperature and IONP content. PFH-NDs containing 5% w/v IONP converted to microbubbles at 42 °C at 2.18 MI, which is just above the exposure limits of 1.9 MI allowed by the FDA for clinical ultrasound scanners, whereas 10 and 15% emulsion vaporized at 1.87 and 1.24 MI, respectively. Furthermore, 5% IONP-loaded PFH-NDs injected intravenously into melanoma-bearing mice at a dose of 120 mg PFH/kg, converted into detectable microbubbles in vivo 5 h, but not shortly after injection, indicating that this technique detects NDs accumulated in tumors.

Electrochemical paper based cancer biosensor using iron oxide nanoparticles decorated PEDOT:PSS

We report results of the studies relating to the fabrication of a label-free, flexible, light weight and disposable conducting paper based immunosensing platform comprising of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) and nanostructured iron oxide (nFe2O3@PEDOT:PSS) nanocomposite for detection of carcinoembryonic antigen (CEA), a cancer biomarker. The effect of various solvents such as sorbitol, ethanol, propanol, n-methyl-2-pyrrolidone (NMP) and dimethyl sulfoxide (DMSO) on the electrical conductivity of Whatman filter paper (WP) modified with nFe2O3@PEDOT:PSS/WP was investigated. The electrical conductivity of the PEDOT:PSS/WP electrode was found to be enhanced by two orders of magnitude (from 6.8× 10−4 to 1.92 × 10−2 Scm−1) after its treatment with DMSO. Further, nFe2O3 doped PEDOT:PSS/WP electrode exhibited the electrical conductivity as 2.4 × 10−2 Scm−1. Besides this, the incorporation of iron oxide nanoparticles (nFe2O3) into PEDOT:PSS/WP resulted in improved electrochemical performance and signal stability. This nFe2O3@PEDOT:PSS/WP based platform was used for immobilization of the anti-carcinoembronic antigen (anti-CEA) protein for quantitative estimation of cancer biomarker (CEA). The results of electrochemical response studies revealed that this conducting paper based immunoelectrode had a sensitivity of 10.2 μAng−1mLcm−2 in the physiological range (4–25 ngmL−1) and shelf life of 34 days. Further, the proposed immunoelectrode was validated with conventional ELISA for the detection of CEA in serum samples of cancer patients.

Assessment of iron oxide nanoparticle ecotoxicity on regeneration and homeostasis in the replacement model system Schmidtea mediterranea_suppl

Iron oxide nanoparticles (IONs) are used in a number of applications from food to cosmetics and from medical applications to magnetic storage. In spite of the 550 tons produced each year in Europe alone, no effective dose limit recommendations are established and the overall risks connected to IONs are still debated. The incorporation of IONs in daily life raises a concern about their effects on the environment, on living organisms, and on human health. In this study, we used freshwater planarians to assess the nanoecotoxicity of IONs. Planarians are free-living invertebrates known for their astonishing regenerative ability. Because of their sensitivity to toxicants, they are often used to determine the effects of toxic, genotoxic, and carcinogenic environmental compounds with an approach in line with the 3Rs (Reduce, Refine, Replace) principle. Planarians were exposed to IONs at concentrations up to 1 mg/ml and their effects were evaluated at the behavioral, morphofunctional, and molecular levels, with a special emphasis on the regeneration process. Our results indicate that IONs did not affect the stem cell population dynamics, nor did they induce substantial changes in either homeostatic or regenerating planarians. As positive controls, gold nanoparticles coated with the pro-apoptotic anti-cancer drug hexadecylmethylammonium bromide and highly concentrated polystyrene nanoparticles were used; these all elicited toxic effects. Therefore, we conclude that IONs at environmental concen­trations are safe for planarians, and that the planarian is a powerful model system that can replace vertebrate animal models in nanoecotoxicology research and for nanoecotoxicology studies.

Assessment of iron oxide nanoparticle ecotoxicity on regeneration and homeostasis in the replacement model system Schmidtea mediterranea.

Iron oxide nanoparticles (IONs) are used in a number of applications, from food to cosmetics, from medical applications to magnetic storage. In spite of the 550 tons produced each year in Europe alone, no effective dose limit recommendations are established and the overall risks connected to IONs are still debated. The incorporation of IONs in daily life raises a concern about their effects on the environment, on living organisms, and on human health. In this study, we used freshwater planarians to assess the nanoecotoxicity of IONs. Planarians are free-living invertebrates known for their astonishing regenerative ability. Because of their sensitivity to toxicants, they are often used to determine the effects of toxic, genotoxic and carcinogenic environmental compounds with an approach in line with the 3Rs (Reduce, Refine, Replace) principle. Planarians were exposed to IONs at concentrations up to 1 mg/mL and their effects were evaluated at the behavioral, morphofunctional and molecular levels, with a special emphasis on the regeneration process. Our results indicate that IONs did not affect the stem cell population dynamics, nor did they induce substantial changes in either homeostatic or regenerating planarians. As positive controls, gold nanoparticles coated with the pro-apoptotic anti-cancer drug hexadecylmethylammonium bromide, silver nanoparticles and highly concentrated polystyrene nanoparticles were used. These all elicited toxic effects. Therefore, we conclude that IONs at environmental concentrations are safe for planarians, and that the planarian is a powerful model system that can replace vertebrate animal models in nanoecotoxicology research and for nanoecotoxicology studies.

Comparing Strategies for Magnetic Functionalization of Microbubbles.

The advancement of ultrasound-mediated therapy has stimulated the development of drug-loaded microbubble agents that can be targeted to a region of interest through an applied magnetic field prior to ultrasound activation. However, the need to incorporate therapeutic molecules while optimizing the responsiveness to both magnetic and acoustic fields and maintaining adequate stability poses a considerable challenge for microbubble synthesis. The aim of this study was to evaluate three different methods for incorporating iron oxide nanoparticles (IONPs) into phospholipid-coated microbubbles using (1) hydrophobic IONPs within an oil layer below the microbubble shell, (2) phospholipid-stabilized IONPs within the shell, or (3) hydrophilic IONPs noncovalently bound to the surface of the microbubble. All microbubbles exhibited similar acoustic response at both 1 and 7 MHz. The half-life of the microbubbles was more than doubled by the addition of IONPs by using both surface and phospholipid-mediated loading methods, provided the lipid used to coat the IONPs was the same as that constituting the microbubble shell. The highest loading of IONPs per microbubble was also achieved with the surface loading method, and these microbubbles were the most responsive to an applied magnetic field, showing a 3-fold increase in the number of retained microbubbles compared to other groups. For the purpose of drug delivery, surface loading of IONPs could restrict the attachment of hydrophilic drugs to the microbubble shell, but hydrophobic drugs could still be incorporated. In contrast, although the incorporation of phospholipid IONPs produced more weakly magnetic microbubbles, it would not interfere with hydrophilic drug loading on the surface of the microbubble.

In-situ electrochemically deposited Fe3O4 nanoparticles onto graphene nanosheets as amperometric amplifier for electrochemical biosensing applications

A novel in-situ approach based on electrochemical techniques has been developed for incorporating iron oxide nanoparticles onto CVD-grown few-layered graphene nanosheets. The embedment of Fe3O4 nanoparticles within graphitic planes was realized by sweeping conductive Gr electrode in a diluted solution of ultrafast redox probe K3[Fe(CN)]6. The morphology and chemical composition of the modified graphene sheets were probed by Scanning Electron Microscopy and Energy Dispersive X-ray analysis, respectively. X-ray photoelectron spectroscopy technique was also employed to provide deeper insights on material structure. Electrochemical behavior of the material was then examined by Cyclic Voltammetry and Electrochemical Impedance Spectroscopy. The results clearly revealed that graphene sheets were evenly decorated by Fe3O4 particles with relatively uniform size of less than 50 nm. The presence of such ‘ceramic’ particles has provided active sites for promoting electron transfer from redox-active species in the solution. Meanwhile, the electrochemical reduction of imperfect graphene sheets has greatly restricted the oxygen moieties, thus improving the conductivity of the material. As a consequence, an increase in amperometric current response of at least 20-fold was recorded after the graphene sheets were electrochemically tailored with iron-based nanoparticles. The graphene-Fe3O4 nanocomposites were then applied for sensing H2O2 (non-enzymatic), glucose and acetylthiocholine (enzymatic). The developed sensors had excellent performances with detection limits of 4.4, 8.2 and 8.35 μM for H2O2, glucose and acetylthiocholine, respectively.

Preparation of Magnetic Polymers for the Elimination of 3-Isobutyl-2-Methoxypyrazine from Wine.

3-Isobutyl-2-methoxypyrazine (IBMP), the most prevalent grape-derived methoxypyrazine, can contribute green bell pepper, vegetative and herbaceous aromas and flavours to wines. At elevated concentrations, this potent odorant may mask desirable fruity and floral aromas in wine and may be considered as a fault. A new remediation method for wines with elevated IBMP levels has been trialled using magnetic polymers, prepared in the same way as ordinary polymers but with the incorporation of iron oxide nanoparticles as magnetic substrates. Characterisation by Fourier transform-infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) showed no difference between thermally synthesised and microwave synthesised polymers. Magnetic polymers were found to have removed over 40% of the IBMP present in spiked model wine and white wine within ten minutes. The addition of magnetic nanoparticles and microwave-induced polymerisation did not affect the adsorption properties of the polymer in model wine and the polymer could be regenerated at least five times. Both Langmuir and Freundlich isotherms were found to fit the data for both types of polymer. However, attempts to produce imprinted polymers were not achieved, as they were found not to be differentiated from non-imprinted counterparts via adsorption tests.

Hydrogel Composite Membranes Incorporating Iron Oxide Nanoparticles as Topographical Designers for Controlled Heteronucleation of Proteins

In this study, we exploited the possibility of tuning physical–chemical properties of hydrogel composite membranes (HCMs) surfaces, by using iron oxide nanoparticles (NPs) as topographical designers, with the aim of examining the effect of surface topography and wettability on the heterogeneous nucleation of protein crystals. On the basis of roughness and contact angle measurements, it was found that surface structural characteristics, in addition to chemical interactions between the surface and protein molecules, have influence on the heterogeneous nucleation of lysozyme and thermolysin crystals to different extents. We demonstrated that increasing the amount of NPs incorporated in the hydrogel matrix promotes protein nucleation to a higher extent, potentially due to the increase of local solute concentration, arising from the enhanced wetting tendency in the Wenzel regime, and physical confinement at rougher hydrophilic surfaces. An extensive crystallographic analysis suggested the tendency of the growi...

Magnetically Assisted Electrodeposition of Aligned Collagen Coatings.

Well-aligned collagen nanofibers are crucial in engineering bioinspired regenerative strategies, such as bone, muscle and cornea. However, keeping the natural bioactive of collagen and controlling its orientation in a coating still remain a challenge. Here we present a novel magnetically assisted electrochemical technique to deposit type-I collagen nanofibers with high alignment onto titanium. The magnetic assistance involved mainly the incorporation of iron oxide nanoparticles (IOPs) and the application of an external magnetic field during the electrochemical deposition. The combination of IOPs with the collagen nanofibrils in electrolyte endowed the nanofibrils with magnetism, which forced the collagen nanofibrils to be straightened and assembled into aligned nanofibers under magnetic field during electrodeposition. The influence of the applied magnetic field on orientational order of the collagen nanofibers in the coatings extended to drying stage. The aligned collagen coatings demonstrated to favorably guide the bone marrow mesenchymal stem cells (BMSCs) grow in the form of elongated morphology, which promoted the cellular osteogenic differentiation dramatically. The present magnetically assisted electrodeposition could emerge as an attractive approach to fabrication of aligned nanofibers on substrates for subsequent uses such as bone tissue engineering.

Producing a magnetically anisotropic soft material: synthesis of iron oxide nanoparticles in a carrageenan/PVA matrix and stretching of the hybrid gelatinous bulk

We propose a method for preparing magnetically anisotropic soft materials that includes chemical loading (in situ synthesis) of iron oxide nanoparticles in a matrix composed of κ-carrageenan (Car) and poly(vinyl alcohol) (PVA) followed by mechanical stretching of the hybrid in a wet process. Anionic Car was used to accommodate the iron oxide nanoparticles and was blended in advance with PVA, which has the ability of high orientation. Scanning electron microscopy revealed that the loaded granular iron oxide nanoparticles (50–100 nm) formed elliptical clusters upon stretching of the hybrid composite. Wide-angle X-ray diffraction measurements indicated that the PVA constituent was oriented in the draw direction. With the orientation of the composite matrix, the incorporated iron oxide nanoparticles gathered to form elliptical clusters. The drawn samples showed different amplitudes in the magnetization (M|| > M⊥) when measured in two setups in which the applied field was parallel (||) or perpendicular (⊥) to the draw direction. The specific responses of the drawn sheets to an external magnetic stimulus were visualized and were reasonably attributed to an effect of the magnetic anisotropy created by the preferred orientation of the nanoparticle aggregates. We prepared magnetically anisotropic soft materials by in situ synthesis of iron oxide nanoparticles in a matrix composed of κ-carrageenan and PVA followed by mechanical stretching of the hybrid in a wet process. With the orientation of the composite matrix, the incorporated iron oxide nanoparticles gathered to form elliptical clusters. The drawn samples showed different magnetizations depending on the direction of magnetic field application. The specific responses were macroscopically visualized and were attributed to the magnetic anisotropy created by the preferred orientation of the nanoparticle aggregates.

Fluorescent Magnetopolymersomes: A Theranostic Platform to Track Intracellular Delivery.

We present a potential theranostic delivery platform based on the amphiphilic diblock copolymer polybutadiene-block-poly (ethylene oxide) combining covalent fluorescent labeling and membrane incorporation of superparamagnetic iron oxide nanoparticles for multimodal imaging. A simple self-assembly and labeling approach to create the fluorescent and magnetic vesicles is described. Cell uptake of the densely PEGylated polymer vesicles could be altered by surface modifications that vary surface charge and accessibility of the membrane active species. Cell uptake and cytotoxicity were evaluated by confocal microscopy, transmission electron microscopy, iron content and metabolic assays, utilizing multimodal tracking of membrane fluorophores and nanoparticles. Cationic functionalization of vesicles promoted endocytotic uptake. In particular, incorporation of cationic lipids in the polymersome membrane yielded tremendously increased uptake of polymersomes and magnetopolymersomes without increase in cytotoxicity. Ultrastructure investigations showed that cationic magnetopolymersomes disintegrated upon hydrolysis, including the dissolution of incorporated iron oxide nanoparticles. The presented platform could find future use in theranostic multimodal imaging in vivo and magnetically triggered delivery by incorporation of thermorepsonsive amphiphiles that can break the membrane integrity upon magnetic heating via the embedded superparamagnetic nanoparticles.

Recent advances in the development of magnetic catalysts for the Suzuki reaction

Suzuki reactions are one of the most important carbon-carbon bond forming reactions found in organic chemistry, with current methodologies offering excellent yields for a wide range of substrates. Further optimisation of such reactions involves incorporation of iron oxide nanoparticles into the catalytic system leading to the formation of highly efficient, recyclable catalysts. This review will focus on the recent development of magnetic palladium catalysts (palladium on magnetite with carbon-based supports and silicon coatings, and palladium on maghemite). Their application and recyclability in Suzuki coupling reactions will also be presented.

Study on the iron oxide/glass nanocomposite materials: fabrication, microstructure and ultrafast nonlinear optical properties

Herein, novel composite glass materials are synthesized by a facile sol–gel approach accompanied with a controlled atmosphere, in which inexpensive iron oxide nanoparticles (NPs) are introduced into sodium borosilicate glasses host. By defining temperature and time limits, two iron oxide NPs with different chemical valence (Fe2O3 NPs and Fe3O4 NPs) were produced in the glass host. The incorporation of iron oxide NPs in a sodium borosilicate glasses matrix vouchsafe the obtained glasses excellent nonlinear optical response. Thus, the Z-scan method using a ultrafast femtosecond laser pulse as fast as 190 fs was employed to evaluate the nonlinear optical feature of as-derived glasses, exhibiting self-focusing effect with reverse saturable absorption. In addition, we have added the new physics analysis of the mechanism on the nonlinear effects in the paper. The obtained results imply that these glass materials are promising candidates for the future development of ultrafast nonlinear devices.

Laser-Fabricated, Self-Forming Swimmers With Catalytic Propulsion and Magnetic Navigation

We have developed an inexpensive rapid process for creating soft, mm-scale self-forming catalytic swimmers for biomedical and environmental applications. The swimmers contain a catalyst such that when exposed to H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> they self-propel. With the additional incorporation of iron oxide nanoparticles (deposited as ferrofluid), we successfully control the navigation of the swimmers using a magnetic field. Unlike the previous reports of catalytic actuators, which use expensive materials (e.g., platinum) and hard substrates (e.g., titanium), our process makes an exclusive use of techniques, which are scalable, economical, and adaptable for large-volume manufacturing (e.g., roll-to-roll), along with materials that are non-toxic and eco-friendly. The devices are created using a planar design, but upon immersion in an aqueous environment, they fold up to create a 3-D architecture, specifically, a tapered cylinder. Tapering is achieved by a range of ablation levels during fabrication, thus creating a gradient of curvatures along the longitudinal axis of the cylinder for improved propulsion efficiency (compared with cylinders or rods). A maximum swimming speed of 7.2 mm/s was observed at 20% H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> .

Quantitative Nanomechanical Properties of Multilayer Films Made of Polysaccharides through Spray Assisted Layer-by-Layer Assembly.

Nanomechanical properties of alginate/chitosan (Alg/Chi) multilayer films, obtained through spray assisted layer-by-layer assembly, were studied by means of PeakForce quantitative nanomechanical mapping atomic force microscopy (PF-QNM AFM). Prepared at two different alginate concentrations (1.0 and 2.5 mg/mL) and a fixed chitosan concentration (1.0 mg/mL), Alg/Chi films have an exponential growth in thickness with a transition to a linear growth toward a plateau by increasing the number of deposited bilayers. Height, elastic modulus, deformation, and adhesion maps were simultaneously recorded depending on the number of deposited bilayers. The elastic modulus of Alg/Chi films was found to be related to the mechanism of growth in contrast to the adhesion and deformation. A comparison of the nanomechanical properties obtained for non-cross-linked and thermally cross-linked Alg/Chi films revealed an increase of the elastic modulus after cross-linking regardless alginate concentration. The incorporation of iron oxide nanoparticles (NPs), during the spray preparation of the films, gave rise to nanocomposite Alg/Chi films with increased elastic moduli with the number of incorporated NPs layers. Deformation maps of the films strongly suggested the presence of empty spaces associated with the method of preparation. Finally, adhesion measurements point out to a significant role of NPs on the increase of the adhesion values found for nanocomposite films.

Controlling Hydrogel Mechanics via Bio-Inspired Polymer-Nanoparticle Bond Dynamics.

Interactions between polymer molecules and inorganic nanoparticles can play a dominant role in nanocomposite material mechanics, yet control of such interfacial interaction dynamics remains a significant challenge particularly in water. This study presents insights on how to engineer hydrogel material mechanics via nanoparticle interface-controlled cross-link dynamics. Inspired by the adhesive chemistry in mussel threads, we have incorporated iron oxide nanoparticles (Fe3O4 NPs) into a catechol-modified polymer network to obtain hydrogels cross-linked via reversible metal-coordination bonds at Fe3O4 NP surfaces. Unique material mechanics result from the supra-molecular cross-link structure dynamics in the gels; in contrast to the previously reported fluid-like dynamics of transient catechol-Fe(3+) cross-links, the catechol-Fe3O4 NP structures provide solid-like yet reversible hydrogel mechanics. The structurally controlled hierarchical mechanics presented here suggest how to develop hydrogels with remote-controlled self-healing dynamics.

Magnetic Bacterial Nanocellulose for neurovascular reconstruction in cerebral aneurysm treatment applications

Event Abstract Back to Event Magnetic Bacterial Nanocellulose for neurovascular reconstruction in cerebral aneurysm treatment applications Sandra L Arias1, 2*, Akshath Shetty2, 3, Angana Senpan2, Monica Echeverry-Rendon4 and Jean Paul Allain2, 3 1 University of Illinois at Urbana-Champaign, Department of Bioengineering, United States 2 University of Illinois at Urbana-Champaign, Micro and Nanotechnology Laboratory, United States 3 University of Illinois at Urbana-Champaign, Department of Nuclear, Plasma and Radiological Engineering, United States 4 University of Antioquia, Department of Materials Engineering, Colombia Introduction: Cerebral aneurysms are abnormal blood pockets that form outside of the arterial wall in the brain. The main obstacle in aneurysmal neuroendovascular reconstruction approaches is the delayed closure of the aneurysm due to poor cell retention[1]. We hypothesized that a magnetic bacterial nanocellulose (MBNC) can improve local cell retention at the site of the aneurysmal neck defect via focal magnetic attractive forces. Bacterial nanocellulose (BNC) is a natural hydrogel produced by A. Xylinum, which has high mechanical properties (114 GPa for a single filament of BNC)[2], and is biocompatible[3]. To test the feasibility of our approach, we precipitated iron oxide nanoparticles (IONPs) in BNC pellicles to yield a magnetic hydrogel, and characterized the resulting material via XPS, SEM and vibrating sample magnetometer (VSM). We additionally introduced cell adhesion sites (collagen) on the MBNC via 1-cyano-4-dimethylaminopyridinium tetrafluoroborate (CDAP) activation of the cellulose fibrils. A cytotoxicity test based on intracellular esterase activity was used to test the biocompatibility of the MBNC pellicles. Materials and Methods: Magnetic functionalization: The MBNC was prepared by in-situ precipitation of Fe2+ and Fe3+ ferrous ions in never-dried BNC[4]. Collagen bio-conjugation: 100 ul of CDAP solution was added on top of BNC and MBNC pellicles and allow to react for 1 min. Subsequently, 0.1 N of HCl was added per sample to stop the activation. The pellicles were washed with PBS and 200 ul of collagen was added on top per sample. The biocompatibility of the samples was tested via calcein/ethidium homodiamer-1 to mark healthy and apoptotic human smooth muscle cells (HSMCs) respectively. MBNC characterization: XPS was employed to reveal the chemical composition both of MBNC and collagen-bioconjugated MBNC pellicles. Magnetic strength via VSM was used to measure the magnetic strength of the MBNC. SEM was used to examine the morphology of the MBNC. Results and Discussion: Fig. 1A shows the set-up used in the fabrication of MBNC. The BNC acquires a black color after incorporation of IONPs, which are dispersed along the BNC fibers or forming aggregates (Fig. 1B-D). Compared with the XPS of BNC (Fig. 2), the spectrum of MBNC shows a significant new signal at a binding energy (BE) of 722 and 709 eV, which is the characteristic peak of Fe 2p1/2 and Fe 2p3/2. The XPS on collagen-conjugated MBNC resulted on the detection of nitrogen, which can be interpreted as an indirect measure of the protein content. Fig. 3 shows the esterase activity measured via calcein (green) of HSMCs culture on MBNC for 24 hours. Both samples show a high HSMC viability and confluence, indicanting that the MBNC and collagen-bioconjugated MBNC did not have negative detrimental effects on HSMCs under these experimental conditions. . The VSM plot of MBNC provide evidence that IONPS are superparamagnetic at room temperature. Conclusion: Our results show that we successfully incorporated Fe3O4 nanoparticles and cell-adhesion sites on the BNC. The VSM data showed that MBNC had a magnetic saturation of (0.054), which is above of the value considered to have satisfactory magnetic strength for tissue engineering purposes (0.049 emu/g). This work was funded by Department of Defense under contract No. W81XWH-11-2-0067

NewTumor-environment biomimetics delay peritoneal metastasis formation by deceiving and redirecting disseminated cancer cells abstract created on Monday June 29, 2015

Event Abstract Back to Event NewTumor-environment biomimetics delay peritoneal metastasis formation by deceiving and redirecting disseminated cancer cells abstract created on Monday June 29, 2015 Elly De Vlieghere1, Marc Bracke1, Pieter Demetter2, Wim Ceelen3, Christain Vanhove4, Bruno G. De Geest5 and Olivier De Wever1 1 Ghent University, Laboratory of Experimental Cancer Research, Belgium 2 Erasme University Hospital, Department of Pathology, Belgium 3 Ghent University Hospital, Department of Surgery, Belgium 4 Ghent University, INFINITY, Belgium 5 Ghent University, Laboratory of Pharmaceutical Technology, Belgium Introduction: Biomimetics of the tumor-environment, an ecosystem, can be applied to create an ecological trap. An ecological trap is an environment of low quality for survival that is preferred by an organism over a better available environment. Carcinoma associated cancer cells (CAFs) produce an extracellular matrix (ECM) that exerts a high attraction to disseminated cancer cells, and is the perfect bait for an ecological trap. Microparticle encapsulated CAFs (MP[CAF]) can redirect adhesion of disseminated cancer cells from the peritoneal wall to the MP[CAF] surface to prevent peritoneal metastasis formation. Materials and Methods: Encapsulation: CAFs cells are encapsulated into microparticles (MP[CAF] 500-700µm) by dripping a mixture of alginate (1.5%), gelatin (0.5%) and CAFs (2.106/ml) in to a CaCl2 bath (1.3%) though a needle (260µm inner diameter) surrounded by an airflow. MP[CAF] where layer-by-layer coated with poly-styrene sulfonate and poly-allyamine (PSS/PAH), with or without the incorporation of iron-oxide nanoparticles between the layers. In vitro confrontation assay: MP[CAF] and MPs without CAFs where confronted with luciferase positive cancer cells (1.105) while shaking. After 48h adhesion the two types of MPs are magnetically separated and the adhesion of SK-OV-3 Luc on the MPs is measured through bioluminescence. In vivo: MP[CAF] (200) are inserted through a small incision in to the abdominal cavity of nude mice. 1.105 ovarian cancer cells (SK-OV-3 Luc IP1) are injected. 24h later MPs with captured cancer cells are removed with a magnet. Sham threated mice underwent the same procedure but now MPs where inserted. Results and Discussion: MP[CAF] are stable and encapsulated CAFs are viable and metabolic active for over 4 weeks. CAF-derived ECM proteins are retained by the PSS/PAH coating. In vitro confrontation show that cancer cells have a higher affinity for MP[CAF] compared to empty MP (fig 1A-B). Small animal MRI imaging shows distribution of MP throughout the abdominal cavity without attachment to intestinal organs and without signs of inflammatory reaction. MP[CAF] trap cancer cells and redirect adhesion away from the wound site. Removal of the MP[CAF] results in a delay peritoneal metastasis formation and a prolonged survival in mice (fig 2A-D). Conclusion: Biomimetics of the tumor-environment by encapsulating CAFs creates an ecological trap for disseminated cancer cells. The present results demonstrate the potential of ecological traps to prevent cancer metastasis. Vlaamse Liga tegen Kanker; Stichting tegen Kanker; IWT

Cobalt Incorporated Pyramidal Shaped &amp;lt;i&amp;gt;α&amp;lt;/i&amp;gt;-Fe&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt; Nanoparticles from Poly-vinyl Alcohol Based Precursor

Precursor foam based Co incorporated α-Fe2O3 (AFC) was successfully synthesized at 600℃ calcination temperature by simple solution method using PVA. The formation of α-Fe2O3 nanoparticles was confirmed by X-ray diffraction measurement and reduction in crystallite size was found after cobalt incorporation. Field emission scanning electron microscopy revealed the existence of pyramidal shaped iron oxide in AFC. FTIR and Raman spectra also confirmed the presence of α-Fe2O3. Photocatalytic activity study showed that the cobalt incorporated α-Fe2O3 was better photocatalyst than pure α-Fe2O3. The cobalt incorporated iron oxide nanoparticles could be used for drug delivery application and this simple preparation method could be adopted for the synthesis of other transition metal oxides.

Incorporation of iron oxide nanoparticles into temperature-responsive poly (N-isopropylacrylamide-co-acrylic acid) P (NIPAAm-AA) polymer hydrogel

Magnetic polymer particles have attracted much attention because of their ubiquitous use in biomedical field such as biomolecule separation, drug carriers, imaging and etc. Iron oxide magnetic nanoparticles were incorporated into temperature responsive poly (N-isopropylacrylamide) (PNIPAAm) polymer hydrogel by a seed polymerization following a surface modification step. Iron oxide magnetic nanoparticles (50–100 nm) prepared by co-precipitation method were modified with silica (SiO2) and 3-(trimethoxysilyl) propyl methacrylate (MPS) to introduce polymerizable vinyl group (−CH = CH2) at the surface of the nanoparticles. Then, the Fe3O4/SiO2/MPS particles were used as seed in polymerization of N-isopropylacrylamide (NIPAAm) and acrylic acid (AA). Here N, N’-methylenebisacrylamide (MBA) and potassium persulphate (KPS) were used as a cross-linker and initiator respectively. Dynamic Light scattering (DLS) results indicated a decrease of hydrodynamic diameter of magnetic Fe3O4/SiO2/MPS/poly (NIPAAm-AA) polymer particles with increasing temperature. Surface functionality and polymer coating, morphology, chemical composition and presence of iron oxide in the magnetic polymer particles were evaluated by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and X-ray diffraction (XRD) respectively. The content of magnetic part was more than 50 wt.% determined by TGA, satisfactory for separation of the final particles from a dispersed media by external magnet. Therefore, the magnetic polymer particles prepared here could be a potential candidate for separation technology.