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Ivanov A.E.,Protista Biotechnology AB | Ivanov A.E.,Lund University | Kumar A.,Indian Institute of Technology Kanpur | Nilsang S.,Asian Institute of Technology | And 8 more authors.
Colloids and Surfaces B: Biointerfaces | Year: 2010

Boronate-containing thin polyacrylamide gels (B-Gel), polymer brushes (B-Brush) and chemisorbed organosilane layers (B-COSL) were prepared on the surface of glass slides and studied as substrates for carbohydrate-mediated cell adhesion. B-COSL- and B-Brush-modified glass samples exhibited multiple submicron structures densely and irregularly distributed on the glass surface, as found by scanning electron microscopy and atomic force microscopy. B-Gel was ca. 0.1 mm thick and contained pores with effective size of 1-2 μm in the middle and of 5-20 μm on the edges of the gel sample as found by confocal laser scanning microscopy. Evidence for the presence of phenylboronic acid in the samples was given by time-of-flight secondary ion mass-spectrometry (ToF SIMS), contact angle measurements performed in the presence of fructose, and staining with Alizarin Red S dye capable of formation specific, fluorescent complexes with boronic acids. A comparative study of adhesion and cultivation of animal cells on the above substrates was carried out using murine hybridoma M2139 cell line as a model. M2139 cells adhered to the substrates in the culture medium without glucose or sodium pyruvate at pH 8.0, and then were cultivated in the same medium at pH 7.2 for 4 days. It was found that the substrates of B-Brush type were superior both regarding cell adhesion and viability of the adhered cells, among the substrates studied. MTT assay confirmed proliferation of M2139 cells on B-Brush substrates. Some cell adhesion was also registered in the macropores of B-Gel substrate. The effects of surface microstructure of the boronate-containing polymers on cell adhesion are discussed. Transparent glass substrates grafted with boronate-containing copolymers offer good prospects for cell adhesion studies and development of cell-based assays. © 2009 Elsevier B.V.

Ivanov A.E.,Protista Biotechnology AB | Solodukhina N.,RAS Shemyakin Ovchinnikov Institute of Bioorganic Chemistry | Wahlgren M.,Lund University | Nilsson L.,Lund University | And 6 more authors.
Macromolecular Bioscience | Year: 2011

Reversible changes of the height of a polymer brush containing phenylboronic acid were studied. The polymer brush thickness underwent reversible changes of 0.5-1nm, in response to the changes in composition of the contacting aqueous phase from deionized water to bicarbonate buffer and vice versa, apparently due to the conformational transition of the weak polyelectrolyte to the more extended electrically charged state. Adsorption of mucin glycoprotein to the polymer brush took place due to boronate/sugar interactions between the glycoprotein and the graft copolymer and resulted in further increase of the brush height by ca. 1.5nm, as observed by means of spectral correlation spectroscopy and ellipsometry. Conformational transitions in polymer brushes are involved in processes like protein binding and cell adhesion. Can these phenomena be quantified by a relatively simple interferometer? The answer is 'yes'. Hydrophilic grafted polymer with pendent groups of phenylboronic acid undergoes reversible transitions in response to pH and binds mucin glycoprotein as detected by spectral correlation spectrometry. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Savina I.N.,University of Brighton | Gun'Ko V.M.,University of Brighton | Gun'Ko V.M.,Chuiko Institute of Surface Chemistry | Turov V.V.,Chuiko Institute of Surface Chemistry | And 4 more authors.
Soft Matter | Year: 2011

The porous structure and the state of the water are two main factors which define the vast applications of hydrogels in the life science arena. The structural characterisation and water state in hydrogels produced by the cryogelation of poly(hydroxyethyl methacrylate) and gelatine were undertaken using different techniques. Images obtained using confocal laser scanning and multiphoton microscopies were analysed using ImageJ/Fiji software to estimate the total porosity, specific surface area and pore size and wall thickness distribution functions of each of the hydrogels. The hydration properties and structural characteristics of the nanopore component of the polymer and protein hydrogels were analysed using DSC, 1H NMR spectroscopy and cryoporometry and modelled using the PM6 quantum chemical method. The hydrogels produced by cryogelation were shown to have a large macropore volume, high pore interconnectivity and small specific surface area. The main portion of water was shown to be attributable to bulk water located within macropores. The relative amounts of bound water in the hydrogels were demonstrated to be small (<10 wt% of bulk water) making macroporous hydrogels an attractive system for biological applications. An understanding of the parameters studied here is important for the future engineering of cryogels for biological applications. © 2011 The Royal Society of Chemistry.

Zheng Y.,University of Brighton | Gun'Ko V.M.,University of Brighton | Gun'Ko V.M.,Chuiko Institute of Surface Chemistry | Howell C.A.,University of Brighton | And 7 more authors.
ACS Applied Materials and Interfaces | Year: 2012

A set of glutaraldehyde (GA) cross-linked poly(vinyl alcohol)/activated carbon (PVA/GA/AC) composites prepared in the form of monolithic rods using a cryogelation technique and studied using adsorption, mercury porosimetry, scanning electron microscopy (SEM), and quantum chemistry methods display porosity similar to that of PVA/GA cryogel at a high GA content (content ratio GA/AC = 1 and GA/PVA = 0.2). GA cross-linked PVA multilayer coverage is an effective barrier for adsorption on AC particles. Variations in surface chemistry (AC initial and oxidized in air at 300 °C for 12 h) and content (14-62.5%w/w) of ACs in PVA/GA/AC composites relatively weakly affect their textural characteristics at a high GA content (specific surface area S BET < 120 m2/g, pore volume Vp < 0.35 cm3/g). However, PVA/GA/AC composite rods formed with a lower concentration of GA (content ratio GA/AC = 1/6 and GA/PVA = 1/10) have significantly greater SBET (∼500 m2/g) and V p (>0.55 cm3/g) values because of improved accessibility of the AC surface. This provides better adsorption of methylene blue as a probe compound. © 2012 American Chemical Society.

Ajore R.,BMC Inc | Dhanda R.S.,Protista Biotechnology AB | Gullberg U.,BMC Inc | Olsson I.,BMC Inc
BMC Molecular Biology | Year: 2010

Background: The Eight-Twenty-One (ETO) nuclear co-repressor gene belongs to the ETO homologue family also containing Myeloid Translocation Gene on chromosome 16 (MTG16) and myeloid translocation Gene-Related protein 1 (MTGR1). By chromosomal translocations ETO and MTG16 become parts of fusion proteins characteristic of morphological variants of acute myeloid leukemia. Normal functions of ETO homologues have as yet not been examined. The goal of this work was to identify structural and functional promoter elements upstream of the coding sequence of the ETO gene in order to explore lineage-specific hematopoietic expression and get hints to function.Results: A putative proximal ETO promoter was identified within 411 bp upstream of the transcription start site. Strong ETO promoter activity was specifically observed upon transfection of a promoter reporter construct into erythroid/megakaryocytic cells, which have endogeneous ETO gene activity. An evolutionary conserved region of 228 bp revealed potential cis-elements involved in transcription of ETO. Disruption of the evolutionary conserved GATA -636 consensus binding site repressed transactivation and disruption of the ETS1 -705 consensus binding site enhanced activity of the ETO promoter. The promoter was stimulated by overexpression of GATA-1 into erythroid/megakaryocytic cells. Electrophoretic mobility shift assay with erythroid/megakaryocytic cells showed specific binding of GATA-1 to the GATA -636 site. Furthermore, results from chromatin immunoprecipitation showed GATA-1 binding in vivo to the conserved region of the ETO promoter containing the -636 site. The results suggest that the GATA -636 site may have a role in activation of the ETO gene activity in cells with erythroid/megakaryocytic potential. Leukemia associated AML1-ETO strongly suppressed an ETO promoter reporter in erythroid/megakaryocytic cells.Conclusions: We demonstrate that the GATA-1 transcription factor binds and transactivates the ETO proximal promoter in an erythroid/megakaryocytic-specific manner. Thus, trans-acting factors that are essential in erythroid/megakaryocytic differentiation govern ETO expression. © 2010 Ajore et al; licensee BioMed Central Ltd.

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