Peptides as capping ligands for in situ synthesis of water soluble Co nanoparticles for bioapplications (original) (raw)
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Applied Surface Science
Cobalt (Co) nanoparticles (NPs) were produced by a simple, one step hydrothermal method with the capping of oleic acid. Intrinsic structural, physiochemical and magnetic properties of Co NPs were investigated and demonstrated their applicability in biomedicine. X-ray diffraction, Raman spectroscopy and infrared (IR) spectroscopic studies confirm the single phase Co NPs with a high structural quality. The IR data revealed the capping of oleic acid via monodentate interaction. Small angle scattering studies suggest the existence of sticky hard sphere type of interaction among the Co NPs because of magnetic interaction which is further evidenced by electron microscopy imaging analyses. The Co NPs exhibit a ferromagnetic character over a wide range of temperature (20-300 K). The temperature dependence of magnetic parameters namely, saturation magnetization, remanent magnetization, coercivity and reduced remanent magnetization were determined and correlated with structure of Co NPs. The Cytotoxicity studies demonstrate that these Co NPs exhibit the mild anti-proliferative character against the cancer cells (cisplatin resistant ovarian cancer (A2780/CP70)) and safe nature towards the normal cells. Haemolytic behaviour of human red blood cells (RBC) revealed (<5%) haemolysis signifying the compatibility of Co NPs with human RBC which is an essential feature in vivo biomedical applications without creating any harmful effects in the human blood stream.
Cobalt magnetic nanoparticles embedded in carbon matrix: biofunctional validation
2012
Carbon nanostructures and nanocomposites display versatile allotropic morphologies, physico-chemical properties and have a wide range of applications in mechanics, electronics, biotechnology, structural material, chemical processing, and energy management. In this study we report the synthesis, characterization, and biotechnological application of cobalt magnetic nanoparticles, with diameter approximately 15-40 nm, embedded in carbon structure (Co/C-MN). A single-step chemical process was used in the synthesis of the Co/C-MN. The Co/C-MN has presented superparamagnetic behavior at room temperature an essential property for immunoseparation assays carried out here. To stimulate interactions between proteins and Co/C-MN, this nanocomposite was functionalized with acrylic acid (AA). We have showed the bonding of different proteins onto Co/C-AA surface using immunofluorescence assay. A Co/C-AA coated with monoclonal antibody antipathogenic Leptospira spp. was able to capture leptospires, suggesting that it could be useful in immunoseparation assays.
Size and shape control for water-soluble magnetic cobalt nanoparticles using polymer ligands
Journal of Materials Chemistry, 2008
We report a synthesis of monodisperse water-soluble magnetic Co nanoparticles using a facile reduction method in aqueous media in the presence of alkyl thioether end-functionalized poly(methacrylic acid) (PMAA-DDT) ligands. The size and shape of the nanoparticles are both tunable by varying synthesis conditions. The size of the spherical nanoparticles can be tuned between 2-7.5 nm by changing the concentration of the polymer. Our synthesis approach also provides a route for producing much larger spherical nanoparticles of 80 nm as well as anisotropic nanorods of 15 Â 36 nm. The spherical nanoparticles are superparamagnetic at room temperature. The nanoparticles can be stable in water for up to eight weeks when 0.12 mM PMAA-DTT with molecular weight of 13500 g mol À1 is used as ligand.
Faraday Discuss., 2014
All reactions were carried out in oven-dried glassware under an atmosphere of dry nitrogen unless stated otherwise. All commercially available reagents were used as received. Carbon coated cobalt nanoparticles were purchased from Turbobeads Llc (Co/C, 20.5 m 2 /g, mean particle size ≈25 nm). Prior to use, they were washed in a concentrated HCl (Merck, puriss)/deionized water (Millipore) mixture (1:1) 5 times for 24 h. Acid residuals were removed by washing with Millipore water (5x) and the particles were dried at 50 _C in a vacuum oven. Carbon coated cobalt nanoparticles were purchased from Turbobeads Llc (Co/C, 20.5 m 2 /g, mean particle size ≈25 nm). Prior to use, they were washed in a concentrated HCl (Merck, puriss)/deionized water (Millipore) mixture (1:1) 5 times for 24 h. Acid residuals were removed by washing with Millipore water (5x) and the particles were dried at 50 °C in a vacuum oven. Pent-4-ynoic acid andhydride, 1 azide functionalized Co/C nanoparticles (loading: 0.14 mmol/g), 2 propargyl-[G3]-(OH) 8 2, 3 propargyl-[G3]-(NH 3 + TFA_) 8 3, 4 Co/C-[G3]
Preparation of functionalized and gold-coated cobalt nanocrystals for biomedical applications
Journal of Magnetism and Magnetic Materials, 2005
We present the synthesis, structural and magnetic characterization of cobalt-based nanocrystals with controlled size (5-25 nm; 71 nm) and tailored morphologies (spheres, discs with specific aspect ratio of 5 Â 20 nm and core-shell structures). The reproducible synthesis route for Au-coated, high moment, cobalt nanocrystals presented here opens up possibilities for a number of biomedical applications and surface functionalities. r 2005 Published by Elsevier B.V.
Controlled cobalt doping in biogenic magnetite nanoparticles
Journal of The Royal Society Interface, 2013
Cobalt-doped magnetite (Co x Fe 3 − x O 4 ) nanoparticles have been produced through the microbial reduction of cobalt–iron oxyhydroxide by the bacterium Geobacter sulfurreducens . The materials produced, as measured by superconducting quantum interference device magnetometry, X-ray magnetic circular dichroism, Mössbauer spectroscopy, etc., show dramatic increases in coercivity with increasing cobalt content without a major decrease in overall saturation magnetization. Structural and magnetization analyses reveal a reduction in particle size to less than 4 nm at the highest Co content, combined with an increase in the effective anisotropy of the magnetic nanoparticles. The potential use of these biogenic nanoparticles in aqueous suspensions for magnetic hyperthermia applications is demonstrated. Further analysis of the distribution of cations within the ferrite spinel indicates that the cobalt is predominantly incorporated in octahedral coordination, achieved by the substitution of ...
Synthesis , characterization and antibacterial properties of nano-sized cobalt particles *
2016
Nano-sized particles exhibit unique and fascinating physical, chemical and biological properties owing to their large surface to volume ratio. The study of nanoparticles interaction with microorganisms is of great importance to consider them for various biomedical applications. The aim of the present study was to study the antibacterial behavior of cobalt oxide (Co2O4) nanoparticles against gram positive and gram negative bacterial strains. Solution based chemical reduction method was used to synthesize the Co2O4 nanoparticles taking cobalt chloride as precursor. The prepared Co2O4 nanoparticles were characterized by X-ray diffraction (XRD) and Variable Sample Magnetometer (VSM) techniques to study the structural and magnetic properties. Kirby-Bauer disk diffusion susceptibility method was used to investigate the in-vitro antimicrobial activity of cobalt nanoparticles. Escherichia coli (E.coli), Pseudomonas aeruginosa (P. aeruginosa) and Bacillus subtilis (B. subtilis) were used to ...
Engineered cobalt oxide nanoparticles readily enter cells
Toxicology Letters, 2009
Magnetic nanoparticles (NPs) have great potential for applications not only as catalysts or energy storage devices, but also in biomedicine, as contrast enhancement agents for magnetic resonance imaging, or for drug delivery. The same characteristics that make cobalt-based NPs so attractive raise serious questions about their safety. In this context, we investigated Co 3 O 4-NPs. Believing that the characterization of NPs is relevant for understanding their biological activity, we analyzed them by atomic force and electron microscopy to define size, shape, and aggregation. To clarify whether their biological effects could be due to a potential release of cobalt ions, we evaluated spontaneous dissolution in different media. To determine their potential toxicity to human cells, we measured cell viability and ROS formation in two human cell lines using CoCl 2 for comparison. Co 3 O 4-NPs induced a concentration-and time-dependent impairment of cellular viability, although cobalt ions were more toxic. We also demonstrated that cobalt causes a rapid induction of ROS if supplied in the form of Co 3 O 4-NPs rather than as ions. Moreover, we evaluated the cellular uptake of NPs. Interestingly, Co 3 O 4-NPs are able to enter the cell very rapidly, remaining confined in vesicles inside the cytoplasm. They were found also inside the cell nuclei, though less frequently.
Surface engineering of Co and FeCo nanoparticles for biomedical application
Journal of Physics: Condensed Matter, 2006
Monodisperse Co, Fe, and FeCo nanoparticles are prepared via thermal decomposition of metal carbonyls in the presence of aluminium alkyls, yielding air-stable magnetic metal nanoparticles after surface passivation. The particles are characterized by electron microscopy (SEM, TEM, ESI), electron spectroscopy (MIES, UPS, and XPS) and x-ray absorption spectroscopy (EXAFS). The particles are peptized by surfactants to form stable magnetic fluids in various organic media and water, exhibiting a high volume concentration and a high saturation magnetization. In view of potential biomedical applications of the particles, several procedures for surface modification are presented, including peptization by functional organic molecules, silanization, and in situ polymerization.