attana - sensor technologies


  • Carbohydrate Polymers, Online 3 February 2017, In press Temperature effect on the complex formation between Pluronic F127 and starchYana Petkova-Olsson, , Samuel Altun, Henrik Ullsten and Lars Järnström

    In this study a systematic investigation of the temperature effect on the interactions between Pluronic F127 and hydroxypropylated oxidised potato starch by surface tension titrations and quartz crystal microbalance (QCM) analysis is presented. The binary mixture examined was subjected to 20 °C and 30 °C and the results indicated no presence of binary complexes at the lower temperature. However, at elevated temperature, an ability for inclusion complex formation was detected by the here used independent techniques. The formed inclusion complexes at 30 °C are presumably a product of hydrophobic interaction between Pluronic F127 and starch, where starch acts as a host molecule and Pluronic F127 due to its increased hydrophobicity is the guest molecule in this complex.

    © 2017 Elsevier Ltd. All rights reserved.

  • Nature: Sci. Rep. 7, 43006; doi: 10.1038/srep43006 (2017) Cellular glycosylation affects Herceptin binding and sensitivity of breast cancer cells to doxorubicin and growth factorsDiluka Peiris, Alexander F. Spector, Hannah Lomax-Browne, TayebehAzimi, Bala Ramesh, Marilena Loizidou, Hazel Welch and Miriam V. Dwek

    Alterations in protein glycosylation are a key feature of oncogenesis and have been shown to affect cancer cell behaviour perturbing cell adhesion, favouring cell migration and metastasis. This study investigated the effect of N-linked glycosylation on the binding of Herceptin to HER2 protein in breast cancer and on the sensitivity of cancer cells to the chemotherapeutic agent doxorubicin (DXR) and growth factors (EGF and IGF-1). The interaction between Herceptin and recombinant HER2 protein and cancer cell surfaces (on-rate/off-rate) was assessed using a quartz crystal microbalance biosensor revealing an increase in the accessibility of HER2 to Herceptin following deglycosylation of cell membrane proteins (deglycosylated cells Bmax: 6.83Hz; glycosylated cells Bmax: 7.35Hz). The sensitivity of cells to DXR and to growth factors was evaluated using an MTT assay. Maintenance of SKBR-3 cells in tunicamycin (an inhibitor of N-linked glycosylation) resulted in an increase in sensitivity to DXR (0.1μM DXR P<0.001) and a decrease in sensitivity to IGF-1 alone and to IGF-1 supplemented with EGF (P<0.001). This report illustrates the importance of N-linked glycosylation in modulating the response of cancer cells to chemotherapeutic and biological treatments and highlights the potential of glycosylation inhibitors as future combination treatments for breast cancer.

    © The Authors 2017 under license from Springer Nature

  • Chem. Commun., 20th September 2016, 52, 12326 Spatially well-defined carbohydrate nanoplatforms: synthesis, characterization and lectin interaction studyB. J. J. Timmer, M. Abellán Flos, L. Mønster Jørgensen, D. Proverbio, S. Altun, O. Ramström, T. Aastrup and S. P. Vincent

    Two novel dodecasubstituted carbohydrate nanoplatforms based on molecular Borromean rings and dodecaamine cages have been prepared for use in evaluating the importance of the spatial distribution of carbohydrates in their interaction with lectins. The binding affinities of the glyconanoplatforms were characterized using quartz crystal microbalance technology and compared with a monovalent reference and dodecaglycosylated fullerenes.

    © The Royal Society of Chemistry 2016

  • Analytical Chemistry, May 6, 2016 Combined Bacteria Microarray and Quartz Crystal Microbalance Approach for Exploring Glycosignatures of Nontypeable Haemophilus influenzae and Recognition by Host LectinsIoanna Kalograiaki, Begoña Euba, Davide Proverbio, María A. Campanero-Rhodes, Teodor Aastrup, Junkal Garmendia and Dolores Solís

    Recognition of bacterial surface epitopes by host receptors plays an important role in the infectious process and is intimately associated with bacterial virulence. Delineation of bacteria−host interactions commonly relies on the detection of binding events between purified bacteria- and host-target molecules. In this work, we describe a combined microarray and quartz crystal microbalance (QCM) approach for the analysis of carbohydrate-mediated interactions directly on the bacterial surface, thus preserving the native environment of the bacterial targets. Nontypeable Haemophilus influenzae (NTHi) was selected as a model pathogenic species not displaying a polysaccharide capsule or O-antigen-containing lipopolysaccharide, a trait commonly found in several important respiratory pathogens. Here, we demonstrate the usefulness of NTHi microarrays for exploring the presence of carbohydrate structures on the bacterial surface. Furthermore, the microarray approach is shown to be efficient for detecting strain-selective binding of three innate immune lectins, namely, surfactant protein D, human galectin-8, and Siglec-14, to different NTHi clinical isolates. In parallel, QCM bacteria-chips were developed for the analysis of lectin-binding kinetics and affinity. This novel QCM approach involves capture of NTHi on lectin-derivatized chips followed by formaldehyde fixation, rendering the bacteria an integrated part of the sensor chip, and subsequent binding assays with label-free lectins. The binding parameters obtained for selected NTHi-lectin pairs provide further insights into the interactions occurring at the bacterial surface.

    © 2016 American Chemical Society

  • Polymer Chemistry, DOI: 10.1039/c5py01954k Facile fabrication of glycopolymer-based iron oxide nanoparticles and their applications in the carbohydrate–lectin interaction and targeted cell imagingChen Shao, Xueming Li, Zhichao Pei, Dongdong Liu, Lin Wang, Hai Dong and
    Yuxin Pei

    A novel method for facile fabrication of glycopolymer-based iron oxide nanoparticles (GIONs) is developed. Via perfluorophenylazide photochemically induced C–H insertion, alkynyl groups were introduced onto the polymer which was precoated on the iron oxide nanoparticle surface. GIONs were then prepared by conjugating the azide-functionalized carbohydrate to the introduced alkynyl groups via click chemistry. Polyvinyl alcohol-coated and dextran-coated iron oxide NPs were chosen as scaffolds to attach two different carbohydrates, α-D-mannose and β-D-glucose, to fabricate multivalent GIONs, respectively. The multivalent GIONs demonstrated high binding affinities towards the corresponding lectins in both protein and cell chips. As a proof of concept, fluorescent GIONs (Gal-RhB-IONPs) were fabricated, which showed selective and efficient internalization by ASGP-R overexpressing HepG2 cells targeted.

    © The Royal Society of Chemistry 2016

  • Tetrahedron; Volume 71, Issue 23, 10 June 2015, Pages 4023–4030 Synthesis and binding affinity analysis of positional thiol analogs of mannopyranose for the elucidation of sulfur in different positionBin Wu, Jiantao Ge, Bo Ren, Zhichao Pei and Hai Dong

    Synthetic routes towards thio-α/β-d-mannose derivatives are presented. Double parallel or double serial inversion was successfully applied in the efficient synthesis of 2-thio- or 2,4-di-thio-mannoside derivatives. The protein recognition properties of the synthesized positional thiol analogs of mannose were then evaluated in a competition binding assay with the model lectin Concanavalin A (Con A), in order to investigate the roles of thiol group in the different position of the mannopyranose ring in binding affinity. Though the substitution of oxygen atom with sulfur atom in the methyl α-d-mannoside ring usually displayed low or no binding affinity towards Con A, it was a surprise finding that the methyl 2-thio-α-d-mannoside displayed four times higher inhibition than methyl α-d-mannoside, indicating the particular importance of 2-position for modification of α-d-mannoside. Methyl 3-thio-α-d-mannoside also displayed inhibition towards Con A, indicating that the O-atom at the C-3 position is less important in the binding site.

    Copyright © 2015 Elsevier Ltd. All rights reserved.

  • J. Agric. Food Chem. 2013, 61, 11400−11409 Inducement of Cytokine Release by GFPBW2, a Novel Polysaccharide from Fruit Bodies of Grifola frondosa, through Dectin‐1 in MacrophagesYing Wang, Jianping Fang, Xinyan Ni, Jie Li, Qin Liu, Qun Dong, Jinyou Duan, and Kan Ding

    Polysaccharides, especially β-glucans isolated from various species of mushrooms, are considered as biological response modifiers (BRMs) to be widely used in the treatment of cancer, especially due to their immunostimulatory activity. We herein characterized the structure of a novel water-soluble homogeneous polysaccharide (GFPBW2) from the fruit bodies of mushroom Grifola frondosa and investigated its immunomodulatory activity in vitro. GFPBW2 was purified from the alkali-extracted fractions by stepwise elution with a molecular weight of 26.2 kDa. On the basis of infrared and NMR spectroscopy, methylation and monosaccharide composition analysis, partial acid hydrolysis, and Smith degradation, its structure was elucidated to possess a backbone consisting of β-D-1,3- and β-D-1,4-linked glucopyranosyl residues, with branches attached to O-6 of β-D-1,3-linked glucopyranosyl residues. Functionally, it is an effective inducer of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) secretion in murine resident peritoneal macrophages. Using quartz crystal microbalance (QCM) analysis, we found that GFPBW2 could bind dendritic cell-associated C-type lectin-1 (Dectin-1) with an affinity constant (Kd) value of 1.08 × 10 −7 M, while it could activate Syk and enhance TNF-α production in RAW264.7 cells overexpressing wild type but not mutant Dectin-1. Furthermore, Syk, NF-κB signaling, and cytokine release in resident peritoneal macrophages induced by GFPBW2 could be significantly inhibited by a specific Dectin-1 blocking reagent, Laminarin. These data suggested that GFPBW2 might be a potential ligand of Dectin-1, and the potential of GFPBW2 to activate macrophage through triggering cytokine secretion might be attributed, at least in part, to the involvement of Dectin-1.

    © 2013 American Chemical Society

  • Chem. Commun., 2014, 50, 731-733 Entropy-driven lectin-recognition of multivalent glycovesiclesZineb Mouline, Eugene Mahon, Emeline Gomez, Veronique Barragan-Montero, Jean-Louis Montero and Mihail Barboiu

    Multivalent glycovesicle recognition over lectin layers emphasizes effects on the dynamic lateral fluidity of glycoside clusters upon multivalent binding at the bilayer surface and vice versa.

    Chem. Commun., 2014, 50, 731

    © The Royal Society of Chemistry 2013

  • Chem. Eur. J. 2014, 20, 1–7 Multivalent Recognition of Concanavalin A by {Mo132} Glyconanocapsules-Toward Biomimetic Hybrid MultilayersBarboiu, Mouline, Silion, Licsandru, Simionescu, Mahon, Pinteala

    Herein, we consider M_ller’s spherical, porous, anionic, molybdenum oxide based capsule, (NH4)42- [{(MoVI)MoVI
    5O21(H2O)6}12{MoV2O4(CH3COO)}30]•10CH3COONH4•300H2O_(NH4)42•1a•crystal ingredients_1, {Mo132}, as an effective sugar-decorated nanoplatform for multivalent lectin recognition. The ion-exchange of NH4+ ions of 1 with cationic-
    sugars, d-mannose-ammonium chloride (2) or d-glucoseammonium chloride (3) results in the formation of glyconanocapsules (NH4)42_n2n•1a and (NH4)42_m3m•1a. The Mannose (NH4)42_n2n•1a capsules bind selectively Concanavalin A (Con A) in aqueous solution, giving an association avidity constant of Kmulti a =4.6_104m_1 and an enhancement factor of b=Kmulti a /Kmono ass =21.9, reminiscent of the formation of “glycoside clusters” on the external surface of glyconanocapsule. The glyconanocapsules (NH4)42_n2n•1a and (NH4)42_m3m•1a self-assemble in “hybrid multilayers” by successive layer-bylayer deposition of (NH4)42_n2n•1a or (NH4)42_m3m•1a and Con A. These architectures, reminiscent of versatile mimics of artificial tissues, can be easily prepared and quantified by using quartz crystal microgravimetry (QCM). The “biomimetic hybrid multilayers” described here are stable under a continual water flow and they may serve as artificial networks for a greater depth of understanding of various biological mechanisms, which can directly benefit the fields of chemical separations, sensors or storage-delivery devices.

    © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • J. Biol. Chem. 2013, 288:995-1008 The C-terminal Peptide of Chondroadherin Modulates Cellular Activity by Selectively Binding to Heparan Sulfate ChainsLisbet Haglund, Viveka Tillgren, Patrik Önnerfjord and Dick Heinegård

    Chondroadherin, a leucine-rich repeat family member, contains a very C-terminal sequence CKFPTKRSKKAGRH359, now shown to bind to heparin with a KD of 13 µM. This observation led us to investigate whether chondroadherin interacts via this C-terminal heparin-binding domain with glycosaminoglycan chains of proteoglycans at the cell surface. Cells were shown to bind this heparin-binding peptide in FACS analysis, and the interaction was shown to be with glycosaminoglycans because it was abolished when sulfation was inhibited by chlorate treatment of the cells. In separate experiments, heparin and heparin sulfate inhibited the peptide interaction in a dose-dependent manner. Using a human chondrosarcoma and a murine osteoblast cell line, heparan sulfate proteoglycans were identified as the cell surface receptors involved in the binding. Different binding syndecans were identified in the two different cell lines, indicating that the same protein core of a proteoglycan may have structural and functional differences in the attached heparan sulfate chains. Upon binding to coated peptide, cells spread, demonstrating engagement of the cytoskeleton, but no focal adhesion complex was formed. The number of cells adhering via their β1 integrin receptor to collagen type II or chondroadherin was profoundly and rapidly enhanced by the addition of the heparin-binding peptide. The peptide added to the cells caused ERK phosphorylation, showing that it triggered intracellular signaling. The results show that heparan sulfate chains differ between various members of the proteoglycan families on a given cell, but also differ between the same proteoglycan on different cells with a potential for differential regulation of cellular activities.

    © 2013 by The American Society for Biochemistry and Molecular Biology, Inc.

  • ChemComm, 30 July 2013 A suspension-cell biosensor for real-time determination of binding kinetics of protein–carbohydrate interactions on cancer cell surfacesXueming Li, Yuxin Pei, Ruina Zhang, Qi Shuai, Feng Wang, Teodor Aastrup and Zhichao Pei

    A novel lectin-based suspension-cell biosensor for label-free determination of binding kinetics of protein–carbohydrate interactions on cancer cell surfaces using QCM is described. This cell-biosensor facilitates evaluation of glycosylation in real time on suspension cancer cell surfaces, where binding events take place, more closely mimicking a native environment compared with traditional biosensors.

    © The Royal Society of Chemistry 2013


  • Biosensors and Bioelectronics, 34 (2012) 51–56 Photogenerated lectin sensors produced by thiol-ene/yne photo-click chemistry in aqueous solutionOscar Norberg, Irene H. Lee, Teodor Aastrup, Mingdi Yan and Olof Ramström

    The photoinitiated radical reactions between thiols and alkenes/alkynes (thiol-ene and thiol-yne chemistry) have been applied to a functionalization methodology to produce carbohydrate-presenting surfaces for analyses of biomolecular interactions. Polymer-coated quartz surfaces were functionalized with alkenes or alkynes in a straightforward photochemical procedure utilizing perfluorophenylazide (PFPA) chemistry. The alkene/alkyne surfaces were subsequently allowed to react with carbohydrate thiols in water under UV-irradiation. The reaction can be carried out in a drop of water directly on the surface without photoinitiator, and any disulfide side products were easily washed away after the functionalization process. The resulting carbohydrate-presenting surfaces were evaluated in real-time studies of protein–carbohydrate interactions using a quartz crystal microbalance (QCM) flow-through system with recurring injections of selected lectins, with intermediate regeneration steps using low pH buffer. The resulting methodology proved fast, efficient and scalable to high-throughput analysis formats, and the produced surfaces showed significant protein binding with expected selectivities of the lectins used in the study.

    © 2012 Elsevier B.V.

  • J Biol Chem. 2011 Oct 14;286(41):35699-707 Unbinding of hyaluronan accelerates the enzymatic activity of bee hyaluronidaseIliás, Liliom, Greiderer-Kleinlercher, Reitinger, Lepperdinger

    Hyaluronan (HA), a polymeric glycosaminoglycan ubiquitously present in higher animals, is hydrolyzed by hyaluronidases (HAases). Here, we used bee HAase as a model enzyme to study the HA-HAase interaction. Located in close proximity to the active center, a bulky surface loop, which appears to obstruct one end of the substrate binding groove, was found to be functionally involved in HA turnover. To better understand kinetic changes in substrate interaction, binding of high molecular weight HA to catalytically inactive HAase was monitored by means of quartz crystal microbalance technology. Replacement of the delimiting loop by a tetrapeptide interconnection increased the affinity for HA up to 100-fold, with a K(D) below 1 nm being the highest affinity among HA-binding proteins surveyed so far. The experimental data of HA-HAase interaction were further validated showing best fit to the theoretically proposed sequential two-site model. Besides the one, which had been shown previously in course of x-ray structure determination, a previously unrecognized binding site works in conjunction with an unbinding loop that facilitates liberation of hydrolyzed HA.

    © 2011 by The American Society for Biochemistry and Molecular Biology, Inc.

  • Analytical Chemistry (2011) 83: 1000-1007 Photo-Click Immobilization on Quartz Crystal Microbalance Sensors for Selective Carbohydrate-Protein Interaction AnalysesOscar Norberg, Lingquan Deng, Teodor Aastrup, Mingdi Yan and Olof Ramström

    A photoclick method based on azide photoligation and Cu-catalyzed azide-alkyne cycloaddition has been evaluated for the immobilization of carbohydrates to polymeric materials. The biomolecular recognition properties of the materials have been investigated with regard to applicable polymeric substrates and selectivity of protein binding. The method was used to functionalize a range of polymeric surfaces (polystyrene, polyacrylamide, poly(ethylene glycol), poly(2-ethyl-2-oxazoline), and polypropene) with various carbohydrate structures (based on R-D-mannose, β-D-galactose, and N-acetyl-β-D-glucosamine). The functionalized surfaces were evaluated in real-time studies of protein-carbohydrate interactions using a quartz crystal microbalance flow-through system with a series of different carbohydrate-binding proteins (lectins). The method proved to be robust and versatile, resulting in a range of efficient sensors showing high and predictable protein selectivities.

    © 2010 American Chemical Society

  • Analytical Bioanalytical Chemistry (2010) 396: 1373-1380 Quartz crystal microbalance, a valuable tool for elucidation of interactions between apoB-100 peptides and extracellular matrix componentsLucia D’Ulivo, Julien Saint-Guirons, Björn Ingemarsson and Marja-Liisa Riekkola

    Atherosclerosis has received wide attention as a primary cause of premature death in developed countries. The retention of low-density lipoprotein (LDL) particles in the intima, the inner layer of the capillaries, has been imputed as the main cause of the development of atherosclerotic plaques. The entrapment of LDL is mainly due to the specific interaction between the lysine-rich site on apolipoprotein B-100 (apoB-100), a major apolipoprotein of LDL, and extracellular matrix (ECM) components such as collagen, proteoglycans, and glycosaminoglycans (GAGs). Although valuable techniques already exist for studies on apoB-100 and ECM interactions, there is continued need for miniaturized tools that can complement the tools already available and even provide totally new data. This work explores the applicability of the quartz crystal microbalance (QCM) for interaction studies between apoB-100 peptide fragments and various components of the ECM. Two positive peptide fragments, PP and PP2, and two components of the ECM, collagen I and a selected GAG, chondroitin 6-sulfate (C6S), were immobilized on polystyrene and carboxyl sensor chips. C6S was injected as analyte for PP- and PP2-coated surfaces, while PP was the analyte for collagen I and C6S surfaces. The estimated dissociation constant (KD) indicates that the interactions occur via the positive residues, lysine and arginine, of apoB-100. The continuous-flow QCM system employed in this study is shown to be an excellent tool for the elucidation of interactions between these types of biomolecules.

    © Springer-Verlag 2009

  • Bioconjugate Chemistry, Vol. 20, Issue 12, 2364-2370, Dec. 2009 Photo-Click Immobilization of Carbohydrates on Polymeric Surfaces-A Quick Method to Functionalize Surfaces for Biomolecular Recognition StudiesOscar Norberg, Lingquan Deng, Mingdi Yan and Olof Ramström

    Methods to rapidly functionalize specific polymeric surfaces with alkynes, which can subsequently be linked to azide-containing carbohydrates, are presented. The methods comprise two main concepts: azide photoligation and Cu-catalyzed azide-alkyne cycloaddition. 2-Azidoethyl-functionalized alpha-d-mannopyranoside was synthesized and covalently attached to alkyne-functionalized polymeric surfaces using the techniques. The protein recognition properties of the carbohydrate-presenting surfaces were evaluated using quartz crystal microbalance biosensor instrumentation.

    © 2009 American Chemical Society

  • Analytical Chemistry 79 (18): 6897-6902 (Sep. 15, 2007) Photoderivatized Polymer Thin Films at Quartz Crystal Microbalance Surfaces: Sensors for Carbohydrate-Protein InteractionsYuxin Pei, Hui Yu, Zhichao Pei, Matthias Theurer, Carolin Ammer, Sabine André, Hans-Joachim Gabius, Mingdi Yan and Olof Ramström

    Photoderivatized polymer-coated gold surfaces have been developed following a perfluorophenylazide-based double ligation strategy. Gold-plated quartz crystal microbalance (QCM) crystals were initially covalently functionalized with a monolayer of poly(ethylene glycol) (PEG), using photo- or thermolytic nitrene formation and insertion. The polymer surfaces were subsequently used as substrates for photoinsertion of carbohydrate-derivatized photoprobes, yielding different recognition motifs for selective protein binding. The resulting robust and biocompatible sensor surfaces were applied to a flow-through QCM instrument for monitoring lectin-carbohydrate interactions in real time. The results clearly show the predicted lectin selectivity, demonstrating the applicability of the approach.

    © 2007 American Chemical Society. All rights reserved.

  • Biosensors and Bioelectronics 22 (2006) 42–48 Quartz crystal microbalance bioaffinity sensor for rapid identification of glycosyldisulfide lectin inhibitors from a dynamic combinatorial libraryZhichao Pei, Rikard Larsson, Teodor Aastrup, Henrik Anderson, Jean-Marie Lehn and Olof Ramström

    Carbohydrate–lectin interactions were probed with dynamic combinatorial libraries, using the plant lectin Concanavalin A as target species. The dynamic combinatorial libraries were generated from a pool of thiol components through reversible thiol–disulfide interchange, and screened using a simple and efficient method based on a quartz crystal microbalance setup. It was found that dimers based on 1-thio- and 6-thio-mannose analogues were the most active inhibitors. Furthermore, the results clearly show that the 6-thio-mannose possess unique characteristics compared to its oxygen-containing counterpart.

    © 2005 Elsevier B.V. All rights reserved.

  • Bioorganic & Medicinal Chemistry Letters 15 (2005) 2707–2710 Redox-responsive and calcium-dependent switching of glycosyldisulfide interactions with Concanavalin AZhichao Pei, Teodor Aastrup, Henrik Anderson and Olof Ramström

    Glycosyldisulfides can interact efficiently with carbohydrate-binding entities. This has been shown for a range of thiosaccharide dimers when tested for their effects against the lectin Concanavalin A using a modified quartz crystal microbalance-technique. Contrary to the thiosaccharide monomers, showing no significant binding up to 10 mM, several of the dimers showed IC50-values in the low millimolar range. Three of the glycosyldisulfides tested also displayed very high positive apparent cooperativity effects that were found to be both calcium-dependent and redox-responsive.

    © 2005 Elsevier Ltd. All rights reserved.

  • Biosensors and Bioelectronics 21 (2005) 60–66 Study of real-time lectin–carbohydrate interactions on the surface of a quartz crystal microbalanceZhichao Pei, Henrik Anderson, Teodor Aastrup and Olof Ramström

    A quartz crystal microbalance (QCM) biosensor system for lectin–carbohydrate interactions has been developed. Yeast mannan was immobilised on polystyrene-coated quartz crystals, and interactions tested with the lectin Concanavalin A (Con A). The biosensor could be easily operated, where mannan immobilisation and all binding analyses were performed in real-time using a flow-through system. The apparent binding constant for yeast mannan to Con A was estimated to be 0.4 _M, well in accordance to reported literature values. In addition, the effective concentration values (EC50-values) for a series of mannose/mannoside ligands, acting as competitors to the mannan/Con A interaction, were determined to range from 0.18 to 5.3 mM, in good correlation with a related enzyme-labeled lectin assay (ELLA) protocol.

    © 2004 Elsevier B.V. All rights reserved.