132 research outputs found
The Nature of Regulatory Autoantibody Changes Among Pregnant Women with Intrauterine Growth Restriction
© 2016, Springer Science+Business Media New York.Anenzyme-linked immunosorbent assay known as ELI-TEST was applied in 388 pregnant women in the gestational complication risk group who were 11– 4 weeks into pregnancy for the purpose of determining the serum content of Ig G class/that bind to double-stranded DNA, β2-glycoprotein I (β2 GP), total phospholipids (TFL), HCG vasculopathy markers (ANCA), collagen (Coll), PAPP-A, and insulin (Ins). After standardizing groups, 80 pregnant women with intrauterine growth restriction (IUGR) were selected for analysis. Characteristic changes in the levels of autoantibodies accompanying IUGR of varying severity were identified which not only gives a more accurate understanding of the pathogenesis of the disease but also enables one to define IUGR risk groups in the early stages of pregnancy
Layer-by-layer coating of bacteria with noble metal nanoparticles for surface-enhanced Raman scattering
A simple layer-by-layer method to coat the bacterial cells with gold and silver nanoparticles (AuNPs and AgNPs) for the acquisition of surface-enhanced Raman scattering (SERS) spectra is reported. First, the bacteria cell wall is coated with poly (allylamine hydrochloride) (PAH), a positively charged polymer, and then with citrate reduced Au or AgNPs. In order to increase the stability of the coating, another layer of PAH is prepared on the surface. The SEM and AFM images indicate that the nanoparticles are in the form of both isolated and aggregated nanoparticles on the bacterial wall. The coating of bacterial cells with AgNPs or AuNPs not only serves for their preparation for SERS measurement but also helps to visualize the coated of bacterial cells under the ordinary white-light microscope objective due to efficient light-scattering properties of Au and AgNPs. A comparative study single versus aggregates of bacterial cells is also demonstrated for possible single bacterial detection with SERS. The two bacteria that differ in shape and cell wall biochemical structure, Escherichia coli and Staphylococcus cohnii, Gram-negative and -positive, respectively, are used as models. The preliminary results reveal that the approach could be used for single bacterial cell identification. © 2009 Springer-Verlag
Cyborg cells: Functionalisation of living cells with polymers and nanomaterials
Living cells interfaced with a range of polyelectrolyte coatings, magnetic and noble metal nanoparticles, hard mineral shells and other complex nanomaterials can perform functions often completely different from their original specialisation. Such "cyborg cells" are already finding a range of novel applications in areas like whole cell biosensors, bioelectronics, toxicity microscreening, tissue engineering, cell implant protection and bioanalytical chemistry. In this tutorial review, we describe the development of novel methods for functionalisation of cells with polymers and nanoparticles and comment on future advances in this technology in the light of other literature approaches. We review recent studies on the cell viability and function upon direct deposition of nanoparticles, coating with polyelectrolytes, polymer assisted assembly of nanomaterials and hard shells on the cell surface. The cell toxicity issues are considered for many practical applications in terms of possible adverse effects of the deposited polymers, polyelectrolytes and nanoparticles on the cell surface. © 2012 The Royal Society of Chemistry
The Possibilities Given by First Trimester Prenatal Screening Data, Uterine Arteries Pulsation Index, and Regulatory Autoantibodies in Predicting Intrauterine Growth Restriction in Females
© 2016, Springer Science+Business Media New York.A combined analysis of pregnancy-associated plasma protein-A (PAPP-A) values, human chorionic gonadotropin, and pulsation index of the uterine arteries was performed as part of a first trimester and serum content of eight regulatory autoantibodies screening. It was found that including autoantibodies to insulin, PAPP-A, and collagen into the analysis significantly improved the sensitivity and specificity of the prognosis and could be employed to form an intrauterine growth restriction (IUGR) risk group
Electrochemical DNA sensors based on nanostructured organic dyes/DNA/polyelectrolyte complexes
© 2014 American Scientific Publishers All rights reserved. Polyelectrolyte complexes based on electropolymerized phenothiazine dyes (Methylene Blue and Methylene Green), poly(allylamine hydrochloride), polystyrene sulfonate and native DNA from salmon sperm have been for the first time obtained by self-assembling on the glassy carbon electrode using the layer-by-layer assembly and characterized using direct current voltammetry and electrochemical impedance spectroscopy. The changes in the charge transfer resistance and capacitance are attributed to the charge separation and the regularity of the layers depending on the number of layers and the position of DNA within the complex. Fenton reagent increases the resistance of the outer interface of the modifier with the maximal effect for the coatings including polymeric form of Methylene Green based coatings and direct contact of the DNA and polyphenothiazines. Meanwhile the selectivity of the response was found higher for the coatings based on poly(Methylene Blue). The difference in the behavior of the polyelectrolyte complex including different components makes it possible to distinguish the response related to the DNA damage and changes in the redox status of polyphenothiazines. Copyrigh
Polyelectrolyte-mediated assembly of multiwalled carbon nanotubes on living yeast cells.
Here we report the three-dimensional assembly of carbon nanotubes on the polyelectrolyte-coated living Saccharomyces cerevisiae cells using the polyelectrolyte-mediated layer-by-layer approach. Synthetic polyelectrolytes poly(allylamine hydrochloride) and poly(sodium 4-styrenesulfonate) were layer-by-layer deposited on the surfaces of the yeast cells followed by the deposition of water-soluble oxidized multiwalled carbon nanotubes (MWNTs) and an additional outermost polyelectrolyte bilayer. This resulted in the fabrication of polyelectrolyte/nanotubes composite coatings on the cell walls of the yeast cells, which could be clearly seen using the conventional optical microscopy. Transmission and scanning electron microscopy was applied to further investigate the composite coatings. Viability of the encapsulated cells was confirmed using the intercellular esterase activity test. Finally, electrochemical studies using voltammetry and electrochemical impedance measurements were performed, indicating that the composite polyelectrolytes/MWNTs coatings sufficiently affect the electron mediation between the encapsulated yeast cells and the artificial electron acceptor, making it possible to distinguish between living and dead cells. The technique described here may find potential application in the development of microelectronic devices, core-shell and hollow composite microparticles, and electrochemical cell-based biosensors
Functional artificial free-standing yeast biofilms
Here we report fabrication of artificial free-standing yeast biofilms built using sacrificial calcium carbonate-coated templates and layer-by-layer assembly of extracellular matrix-mimicking polyelectrolyte multilayers. The free-standing biofilms are freely floating multilayered films of oppositely charged polyelectrolytes and live cells incorporated in the polyelectrolyte layers. Such biofilms were initially formed on glass substrates of circular and ribbon-like shapes coated with thin layers of calcium carbonate microparticles. The templates were then coated with cationic and anionic polyelectrolytes to produce a supporting multilayered thin film. Then the yeast alone or mixed with various micro- and nanoparticle inclusions was deposited onto the multilayer composite films and further coated with outer polyelectrolyte multilayers. To detach the biofilms from the glass substrates the calcium carbonate layer was chemically dissolved yielding free-standing composite biofilms. These artificial biofilms to a certain degree mimic the primitive multicellular and colonial species. We have demonstrated the added functionality of the free-standing artificial biofilms containing magnetic, latex and silver micro- and nanoparticles. We have also developed "symbiotic" multicellular biofilms containing yeast and bacteria. This approach for fabrication of free-standing artificial biofilms can be potentially helpful in development of artificial colonial microorganisms composed of several different unicellular species and an important tool for growing cell cultures free of supporting substrates. © 2011 Elsevier B.V
A whole-cell amperometric herbicide biosensor based on magnetically functionalised microalgae and screen-printed electrodes
We report the fabrication of an amperometric whole-cell herbicide biosensor based on magnetic retention of living cells functionalised with magnetic nanoparticles (MNPs) on the surface of a screen-printed electrode. We demonstrate that Chlorella pyrenoidosa microalgae cells coated with biocompatible MNPs and retained on the electrode with a permanent magnet act as a sensing element for the fast detection of herbicides. The magnetic functionalisation does not affect the viability and photosynthesis activity-mediated triazine herbicide recognition in microalgae. The current of ferricyanide ion was recorded during alternating illumination periods and biosensor fabricated was used to detect atrazine (from 0.9 to 74 M) and propazine (from 0.6 to 120 M) (the limits of detection 0.7 and 0.4 M, respectively). We believe that the methodology presented here can be widely used in fabrication of a number of whole cell biosensors since it allows for efficient and reversible cells immobilisation and does not affect the cellular metabolism. © 2011 The Royal Society of Chemistry
Interfacing Living Unicellular Algae Cells with Biocompatible Polyelectrolyte-Stabilised Magnetic Nanoparticles
Green algae are a promising platform for the development of biosensors and bioelectronic devices. Here we report a reliable single-step technique for the functionalisation of living unicellular green algae Chlorella pyrenoidosa with biocompatible 15 nm superparamagnetic nanoparticles stabilised with poly(allylamine hydrochloride). The magnetised algae cells can be manipulated and immobilised using external permanent magnets. The distribution of the nanoparticles on the cell walls of C. pyrenoidosa was studied by optical and fluorescence microscopy, TEM, SEM and EDX spectroscopy. The viability and the magnetic properties of the magnetised algae are studied in comparison with the native cells. The technique may find a number of potential applications in biotechnology and bioelectronics.We report the functionalisation of viable algae C. pyrenoidosa cells with biocompatible polyelectrolyte-stabilised superparamagnetic nanoparticles via a single-step direct deposition. This study demonstrates that the living magnetised algae cells are susceptible for the spatial manipulation with a permanent magnet, opening new avenues for a number of practical applications, including the fabrication of whole-cell biosensors. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
A direct technique for magnetic functionalization of living human cells
Functionalized living cells are regarded as effective tools in directed cell delivery and tissue engineering. Here we report the facile functionalization of viable isolated HeLa cells with superparamagnetic cationic nanoparticles via a single-step biocompatible process. Nanoparticles are localized on the cellular membranes and do not penetrate into the cytoplasm. The magnetically responsive cells are viable and able to colonize and grow on substrates. Magnetically facilitated microorganization of functionalized cells into viable living clusters is demonstrated. We believe that the technique described here may find a number of potential applications in cell-based therapies and in development of whole-cell biosensors. © 2011 American Chemical Society
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