attana - sensor technologies

Other Macromolecules

  • Anal Bioanal Chem 4 April 2014, DOI 10.1007/s00216-014-7821-9 Partial-filling affinity capillary electrophoresis and quartz crystal microbalance with adsorption energy distribution calculations in the study of biomolecular interactions with apolipoprotein E as interaction partnerLipponen, Tähkä, Samuelsson,Jauhiainen, Metso, Cilpa-Karhu, Fornstedt, Kostiainen, Riekkola

    Adsorption energy distribution (AED) calculations were successfully applied to partial-filling affinity capillary electrophoresis (PF-ACE) to facilitate more detailed studies of biomolecular interactions. PF-ACE with AED calculations was employed to study the interactions between two isoforms of apolipoprotein E (apoE) and dermatan sulfate (DS), and a quartz crystal microbalance (QCM) was used in combination with AED calculations to examine the interactions of the 15-amino-acid peptide fragment of apoE with DS. The heterogeneity of the interactions was elucidated. Microscale thermophoresis was used to validate the results. The interactions studied are of interest because, in vivo, apolipoprotein E localizes on DS-containing regions in the extracellular matrix of human vascular subendothelium. Two-site binding was demonstrated for the isoform apoE3 and DS, but only one-site binding for apoE2–DS. Comparable affinity constants were obtained for the apoE2–DS, apoE3–D3, and 15-amino-acid peptide of apoE–DS using the three techniques. The results show that combining AED calculations with modern biosensing techniques can open up another dimension in studies on the heterogeneity and affinity constants of biological molecules.

    Copyright © Springer-Verlag Berlin Heidelberg 2014

  • 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.

  • Analytical Biochemistry, 414 (2011) 117–124 Polyethylene glycol-stabilized lipid disks as model membranes in interaction studies based on electrokinetic capillary chromatography and quartz crystal microbalanceK. Vainikka, K. Reijmar, G. Yohannes, J. Samuelsson, K. Edwards, M. Jussila, M.-L. Riekkola

    Distearoylphosphatidylcholine (DSPC)/cholesterol/distearoylphosphatidylethanolamine (DSPE)–polyethylene glycol 5000 [PEG(5000)] lipid disks, mimicking biological membranes, were used as pseudostationary phase in partial filling electrokinetic capillary chromatography (EKC) to study interactions between pharmaceuticals and lipid disks. Capillaries were coated either noncovalently with a poly(1-vinylpyrrolidone)-based copolymer or covalently with polyacrylamide to mask the negative charges of the fused-silica capillary wall and to minimize interactions between positively charged pharmaceuticals and capillary wall. Although the noncovalent copolymer coating method was faster, better stability of the covalent polyacrylamide coating at physiological pH 7.4 made it more reliable in partial filling EKC studies. Migration times of pharmaceuticals were proportional to the amount of lipids in the pseudostationary phase, and partition coefficients were successfully determined. Because the capillary coatings almost totally suppressed the electroosmotic flow, it was not practical to use the EKC-based method for partition studies involving large molecules with low mobilities. Hence, the applicability of the biomembrane mimicking lipid disks for interactions studies with large molecules was verified by the quartz crystal microbalance technique. Biotinylated lipid disks were then immobilized on streptavidincoated sensor chip surface, and interactions with a high-molecular-mass molecule, lysozyme, were studied. Cryo-transmission electron microscopy and asymmetrical flow field-flow fractionation were used to clarify the sizes of lipid disks used.

    © 2011 Elsevier Inc.

  • Chemical Communications, Vol. 46, Issue 14, 2441-2443, 2010 Dynamic glycovesicle systems for amplified QCM detection of carbohydrate-lectin multivalent biorecognitionEugene Mahon, Teodor Aastrup and Mihail Barboiu

    We describe multivalent biorecognition of adsorbed lectin layers by biomimetic sensing nanoplatforms based on dynamic glycovesicles in a continuous flow QCM setup.

    © The Royal Society of Chemistry 2010

  • Chemical Communications, Vol 46, Issue: 30, 5491-5493, 2010 Multivalent recognition of lectins by glyconanoparticle systemsMahon E, Aastrup T, Barboiu M

    Multivalent recognition of lectin layers by glyconanoparticle sugar-clusters has been used to study the carbohydrate-protein interactions in a QCM sensing setup.

    © The Royal Society of Chemistry 2010

  • Talanta 77 (2008) 468–472 Flow-injection assay of the pathogenic bacteria using lectin-based quartz crystal microbalance biosensorGulnara Safina, Margret van Lier, Bengt Danielsson

    A novel flow-injection assay of the pathogenic enterobacteria using novel lectin-based quartz crystal microbalance (QCM) biosensor has been proposed. The biosensing part of the analytical device contained the lectins – Concanavalin A, lectins from Ulex europeus, Maackia amurensis, Lens culinaris, wheat germ agglutinin – immobilized on the gold surface of quartz crystal electrode which served as a transducer. The immobilization of lectins was carried out using amine coupling on the surface of the crystal modified with 11-mercaproundecanoic acid. The biosensor makes it possible to identify the presence of different bacterial using the lectins immobilized on the surface of QCM crystal which bind specifically to the certain oligosaccharides present on the cell wall of the bacteria injected. The working conditions of the biosensor – pH of buffer solutions, concentration of the immobilized lectins, dilution of the bacterial cells, regeneration solution and flow rate –were optimized. The use of solution of glycine (pH 2.5) makes it possible to remove the formed complex from the crystal surface to make it reusable and ready for the next experiment. The proposed biosensor is able to detect 10³ cells. The flow-injection assay of the bacterial cells takes about 30 min.

    © 2008 Published by Elsevier B.V.