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Yoshimoto M, Kurosawa S, Tanaka M. Temperature Dependence of the Rheology of Soft Matter on a MHz-oscillating Solid-liquid Interface. J Oleo Sci 2022; 71:905-913. [PMID: 35584960 DOI: 10.5650/jos.ess22049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The temperature dependence of the resonant length, molecular weight, and rheology (shear viscosity and shear modulus) of chemisorbed soft matter on a solid-liquid interface oscillating at a megahertz frequency was studied using a quartz crystal microbalance. As a form of chemisorbed soft matter, self-assembled monolayers (SAMs) formed from six types of mercapto oligo(ethylene oxide) methyl ethers were used. A systematic analysis using the Voigt model showed that the variation in effective hydrated thickness (sensed mass), which is related to the resonant length, was classified into three types based on the molecular weight. As a result, a 2.2-nm change in the resonant length occurred in the studied temperature range from 10 to 35℃. Moreover, the variation in the effective hydrated thickness was dependent on the shear viscosity and shear modulus of the SAMs. A further investigation revealed that the relationships η1∝Mn0.13 and μ1∝Mn0.30 could be estimated regardless of the temperature, where η1 and μ1 are the shear viscosity and shear modulus of the SAM, and Mn is the molecular weight of mercapto oligo(ethylene oxide) methyl ether. As a result, we revealed that the experimental results followed the polymer formula irrespective of temperature.
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Affiliation(s)
- Minoru Yoshimoto
- Department of Information Science and Biomedical Engineering, Graduate School of Science and Engineering, Kagoshima University
| | - Shigeru Kurosawa
- Health Research Institute, National Institute of Advanced Industrial Science and Technology (AIST)
| | - Mutsuo Tanaka
- Department of Life Science & Green Chemistry, Saitama Institute of Technology
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2
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Chávez M, Sánchez-Obrero G, Madueño R, Sevilla JM, Blázquez M, Pineda T. Electrochemical evaluation of the grafting density of self-assembled monolayers of polyethylene glycol of different chain lengths formed by the grafting to approach under conditions close to the cloud point. J Electroanal Chem (Lausanne) 2022. [DOI: 10.1016/j.jelechem.2022.116294] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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3
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Self-assembled monolayers of O-(2-Mercaptoethyl)-O′-methyl-hexa(ethylene glycol) (EG7-SAM) on gold electrodes. Effects of the nature of solution/electrolyte on formation and electron transfer blocking characteristics. J Electroanal Chem (Lausanne) 2022. [DOI: 10.1016/j.jelechem.2022.116303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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4
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Mondarte EAQ, Zamarripa EMM, Chang R, Wang F, Song S, Tahara H, Hayashi T. Interphase Protein Layers Formed on Self-Assembled Monolayers in Crowded Biological Environments: Analysis by Surface Force and Quartz Crystal Microbalance Measurements. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:1324-1333. [PMID: 35029393 DOI: 10.1021/acs.langmuir.1c02312] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We investigated a viscous protein layer formed on self-assembled monolayers (SAMs) in crowded biological environments. The results were obtained through force spectroscopic measurements using colloidal probes and substantiated by exhaustive analysis using a quartz crystal microbalance with an energy dissipation technique. A hydrophobic SAM of n-octanethiol (C8 SAM) in bovine serum albumin (BSA) solution is buried under an adlayer of denatured BSA molecules and an additional viscous interphase layer that is five times more viscous than the bulk solution. C8 SAMs in fetal bovine serum induced a formation of a thicker adsorbed protein layer but with no observable viscous interphase layer. These findings show that a fouling surface is essentially inaccessible to any approaching molecules and thus has a new biological and physical identity arising from its surrounding protein layers. In contrast, the SAMs composed of sulfobetaine-terminated alkanethiol proved to be sufficiently protein-resistant and bio-inert even under crowded conditions due to a protective barrier of its interfacial water, which has implications in the accurate targeting of artificial particles for drug delivery and similar applications by screening any non-specific interactions. Finally, our strategies provide a platform for the straightforward yet effectual in vitro characterization of diverse types of surfaces in the context of targeted interactions in crowded biological environments.
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Affiliation(s)
- Evan Angelo Quimada Mondarte
- Tokyo Institute of Technology, Department of Materials Science and Engineering, School of Materials and Chemical Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502, Japan
| | - Elisa Margarita Mendoza Zamarripa
- Tokyo Institute of Technology, Department of Materials Science and Engineering, School of Materials and Chemical Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502, Japan
| | - Ryongsok Chang
- Tokyo Institute of Technology, Department of Materials Science and Engineering, School of Materials and Chemical Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502, Japan
| | - Fan Wang
- Tokyo Institute of Technology, Department of Materials Science and Engineering, School of Materials and Chemical Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502, Japan
| | - Subin Song
- Tokyo Institute of Technology, Department of Materials Science and Engineering, School of Materials and Chemical Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502, Japan
| | - Hiroyuki Tahara
- Tokyo Institute of Technology, Department of Materials Science and Engineering, School of Materials and Chemical Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502, Japan
| | - Tomohiro Hayashi
- Tokyo Institute of Technology, Department of Materials Science and Engineering, School of Materials and Chemical Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502, Japan
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa, Chiba 277-0882, Japan
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5
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Skoda MWA, Conzelmann NF, Fries MR, Reichart LF, Jacobs RMJ, Zhang F, Schreiber F. Switchable β-lactoglobulin (BLG) adsorption on protein resistant oligo (ethylene glycol) (OEG) self-assembled monolayers (SAMs). J Colloid Interface Sci 2022; 606:1673-1683. [PMID: 34534835 DOI: 10.1016/j.jcis.2021.08.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 07/07/2021] [Accepted: 08/03/2021] [Indexed: 12/16/2022]
Abstract
HYPOTHESIS Although protein adsorption at an interface is very common and important in biology and biotechnology, it is still not fully understood - mainly due to the intricate balance of forces that ultimately control it. In food processing (and medicine), controlling and manipulating protein adsorption, as well as avoiding protein adsorption (biofilm formation or membrane fouling) by the production of protein-resistant surfaces is of substantial interest. A major factor conferring resistance towards protein adsorption to a surface is the presence of tightly bound water molecules, as is the case in oligo ethylene glycol (OEG)-terminated self-assembled monolayers (SAMs). Due to strong attractive protein-protein and protein-surface interactions observed in systems containing trivalent salt ions, we hypothesize that these conditions may lead to a breakdown of protein resistance in OEG SAMs. EXPERIMENTS We studied the adsorption behavior of BLG in the presence of a lanthanum(III) chloride (LaCl3) at concentrations of 0, 0.1, 0.8 and 5.0 mM on normally protein resistant triethylene glycol-termianted (EG3) SAMs on a gold surface. We used quartz-crystal microbalance with dissipation (QCM-D) and neutron reflectivity (NR) to characterize the morphology of the interfacial region of the SAM. FINDINGS We demonstrate that the protein resistance of the EG3 SAM breaks down beyond a threshold salt concentration c∗ and mirrors the bulk behaviour of this system, showing reduced adsorption beyond a second critical salt concentration c∗∗. These results demonstrate for the first time the controlled switching of the protein-resistant properties of this type of SAM by the addition of trivalent salt.
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Affiliation(s)
- Maximilian W A Skoda
- STFC, ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, UK
| | - Nina F Conzelmann
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, Tübingen 72076, Germany
| | - Madeleine R Fries
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, Tübingen 72076, Germany
| | - Lara F Reichart
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, Tübingen 72076, Germany
| | - Robert M J Jacobs
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, South Parks Road, Oxford OX1 3TA, UK
| | - Fajun Zhang
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, Tübingen 72076, Germany
| | - Frank Schreiber
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, Tübingen 72076, Germany.
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6
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Yao Y, Yang J, Li W, Zhang A. Confinements of Thermoresponsive Dendronized Polymers to Proteins. Polym Chem 2022. [DOI: 10.1039/d2py00957a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Crowding environment created by host polymers plays crucial roles in manipulating interactions with proteins and modulating their bioactivity. Here, we report our investigation on interactions between polymers and proteins in...
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7
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Affiliation(s)
- Tomohiro Hayashi
- Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502, Japan
- JST-PRESTO (Materials Informatics), 4-1-8 Hon-cho, Kawaguchi, Saitama 332-0012, Japan
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8
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Characterization of a self-assembled monolayer of O-(2-Mercaptoethyl)-O′-methyl-hexa(ethylene glycol) (EG7-SAM) on gold electrodes. J Electroanal Chem (Lausanne) 2021. [DOI: 10.1016/j.jelechem.2020.114892] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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9
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Zhang P, Ratner BD, Hoffman AS, Jiang S. Nonfouling Surfaces. Biomater Sci 2020. [DOI: 10.1016/b978-0-12-816137-1.00034-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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10
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Maroni P, Gvaramia M, Kosior D, Kubiak K, Scarratt L, Smith AM, Merkel DG, Bottyán L, Borkovec M. Structuring of colloidal silica nanoparticle suspensions near water-silica interfaces probed by specular neutron reflectivity. Phys Chem Chem Phys 2020; 22:6449-6456. [PMID: 32149295 DOI: 10.1039/d0cp00465k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Structuring of aqueous suspensions of colloidal silica nanoparticles near an isolated planar silica-water interface is studied by specular neutron reflectivity. The reflectivity data clearly show that the suspensions develop a damped, oscillatory concentration profile in the normal direction to the interface. The wavelengths of these oscillations agree well with those independently determined by direct force measurements in the slit-geometry. The reflectivity data further demonstrate that the oscillatory structure persists over several layers and that the first particle layer is separated from the interface by a particle-free region.
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Affiliation(s)
- Plinio Maroni
- Department of Inorganic and Analytical Chemistry, University of Geneva, Sciences II, 30 Quai Ernest-Ansermet, 1205 Geneva, Switzerland.
| | - Manuchar Gvaramia
- Department of Inorganic and Analytical Chemistry, University of Geneva, Sciences II, 30 Quai Ernest-Ansermet, 1205 Geneva, Switzerland.
| | - Dominik Kosior
- Department of Inorganic and Analytical Chemistry, University of Geneva, Sciences II, 30 Quai Ernest-Ansermet, 1205 Geneva, Switzerland.
| | - Katarzyna Kubiak
- Department of Inorganic and Analytical Chemistry, University of Geneva, Sciences II, 30 Quai Ernest-Ansermet, 1205 Geneva, Switzerland.
| | - Liam Scarratt
- Department of Inorganic and Analytical Chemistry, University of Geneva, Sciences II, 30 Quai Ernest-Ansermet, 1205 Geneva, Switzerland.
| | - Alexander M Smith
- Department of Inorganic and Analytical Chemistry, University of Geneva, Sciences II, 30 Quai Ernest-Ansermet, 1205 Geneva, Switzerland.
| | - Dániel G Merkel
- Wigner Research Centre for Physics, Konkoly-Thege Miklós út 29-33, 1121 Budapest, Hungary and Centre for Energy Research, Konkoly-Thege Miklós út 29-33, 1121 Budapest, Hungary
| | - László Bottyán
- Wigner Research Centre for Physics, Konkoly-Thege Miklós út 29-33, 1121 Budapest, Hungary
| | - Michal Borkovec
- Department of Inorganic and Analytical Chemistry, University of Geneva, Sciences II, 30 Quai Ernest-Ansermet, 1205 Geneva, Switzerland.
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11
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Yoshimoto M, Kurosawa S, Tanaka M. Temperature dependence of physical properties of soft matters on the oscillating solid-liquid interface. Chem Phys 2019. [DOI: 10.1016/j.chemphys.2019.04.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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12
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Fies WA, Dugger JW, Dick JE, Wilder LM, Browning KL, Doucet M, Browning JF, Webb LJ. Direct Measurement of Water Permeation in Submerged Alkyl Thiol Self-Assembled Monolayers on Gold Surfaces Revealed by Neutron Reflectometry. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:5647-5662. [PMID: 30919634 DOI: 10.1021/acs.langmuir.9b00541] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Self-assembled monolayers (SAMs) of alkyl thiols are frequently used to chemically functionalize gold surfaces for applications throughout materials chemistry, electrochemistry, and biotechnology. Despite this, a detailed understanding of the structure of the SAM-water interface generated from both formation and use of the SAM in an aqueous environment is elusive, and analytical measurements of the structure and chemistry of the SAM-water interface are an ongoing experimental challenge. To address this, we used neutron reflectometry (NR) to measure water association with both hydrophobic and hydrophilic SAMs under both wet and dry conditions. SAMs used for this study were made from hydrophobic decanethiol mixed with hydrophilic 11-azido-1-undecanethiol with compositions of 0-100% of the azide-terminated thiol. All SAMs were formed by conventional solution incubation of a Au substrate immersed in ethanol. Each SAM was characterized by grazing incidence angle reflection-absorption Fourier transfer infrared spectroscopy, contact angle goniometry, and electrochemical methods to confirm it was a completely formed monolayer with evidence of extensive crystalline-like domains. NR measured significant absorption of water into each SAM, ranging from 1.6 to 5.7 water molecules per alkyl thiol, when SAMs were immersed in water. Water infiltration was independent of SAM composition and terminal group hydrophilicity. These results demonstrate that water accesses defects, fluid regions, and heterogeneous domains inherent to even well-formed SAMs.
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Affiliation(s)
- Whitney A Fies
- Department of Chemistry and Texas Materials Institute , The University of Texas at Austin , 2506 Speedway STOP A5300 , Austin , Texas 78712 , United States
| | | | - Jeffrey E Dick
- Department of Chemistry , The University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States
| | - Logan M Wilder
- Department of Chemistry and Texas Materials Institute , The University of Texas at Austin , 2506 Speedway STOP A5300 , Austin , Texas 78712 , United States
| | | | | | | | - Lauren J Webb
- Department of Chemistry and Texas Materials Institute , The University of Texas at Austin , 2506 Speedway STOP A5300 , Austin , Texas 78712 , United States
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13
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Amano KI, Ishihara T, Hashimoto K, Ishida N, Fukami K, Nishi N, Sakka T. Stratification of Colloidal Particles on a Surface: Study by a Colloidal Probe Atomic Force Microscopy Combined with a Transform Theory. J Phys Chem B 2018; 122:4592-4599. [PMID: 29611708 DOI: 10.1021/acs.jpcb.8b01082] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Colloidal probe atomic force microscopy (CP-AFM) can be used for measuring force curves between the colloidal probe and the substrate in a colloidal suspension. In the experiment, an oscillatory force curve reflecting the layer structure of the colloidal particles on the substrate is usually obtained. However, the force curve is not equivalent to the interfacial structure of the colloidal particles. In this paper, the force curve is transformed into the number density distribution of the colloidal particles as a function of the distance from the substrate surface using our newly developed transform theory. It is found by the transform theory that the interfacial stratification is enhanced by an increase in an absolute value of the surface potential of the colloidal particle, despite a simultaneous increase in a repulsive electrostatic interaction between the substrate and the colloidal particle. To elucidate the mechanism of the stratification, an integral equation theory is employed. It is found that crowding of the colloidal particles in the bulk due to the increase in the absolute value of the surface potential of the colloidal particle leads to pushing out some colloidal particles to the wall. The combined method of CP-AFM and the transform theory (the experimental-theoretical study of the interfacial stratification) is related to colloidal crystallization, glass transition, and aggregation on a surface. Thus, the combined method is important for developments of colloidal nanotechnologies.
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Affiliation(s)
- Ken-Ichi Amano
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering , Kyoto University , Kyoto 615-8510 , Japan
| | - Taira Ishihara
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering , Kyoto University , Kyoto 615-8510 , Japan
| | - Kota Hashimoto
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering , Kyoto University , Kyoto 615-8510 , Japan
| | - Naoyuki Ishida
- Division of Applied Chemistry, Graduate School of Natural Science and Technology , Okayama University , Okayama 700-8530 , Japan
| | - Kazuhiro Fukami
- Department of Materials Science and Engineering, Graduate School of Engineering , Kyoto University , Kyoto 606-8501 , Japan
| | - Naoya Nishi
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering , Kyoto University , Kyoto 615-8510 , Japan
| | - Tetsuo Sakka
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering , Kyoto University , Kyoto 615-8510 , Japan
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14
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Fries MR, Stopper D, Braun MK, Hinderhofer A, Zhang F, Jacobs RMJ, Skoda MWA, Hansen-Goos H, Roth R, Schreiber F. Multivalent-Ion-Activated Protein Adsorption Reflecting Bulk Reentrant Behavior. PHYSICAL REVIEW LETTERS 2017; 119:228001. [PMID: 29286772 DOI: 10.1103/physrevlett.119.228001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Indexed: 06/07/2023]
Abstract
Protein adsorption at the solid-liquid interface is an important phenomenon that often can be observed as a first step in biological processes. Despite its inherent importance, still relatively little is known about the underlying microscopic mechanisms. Here, using multivalent ions, we demonstrate the control of the interactions and the corresponding adsorption of net-negatively charged proteins (bovine serum albumin) at a solid-liquid interface. This is demonstrated by ellipsometry and corroborated by neutron reflectivity and quartz-crystal microbalance experiments. We show that the reentrant condensation observed within the rich bulk phase behavior of the system featuring a nonmonotonic dependence of the second virial coefficient on salt concentration c_{s} is reflected in an intriguing way in the protein adsorption d(c_{s}) at the interface. Our findings are successfully described and understood by a model of ion-activated patchy interactions within the framework of the classical density functional theory. In addition to the general challenge of connecting bulk and interface behavior, our work has implications for, inter alia, nucleation at interfaces.
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Affiliation(s)
- Madeleine R Fries
- Institute for Applied Physics, University of Tübingen, 72076 Tübingen, Germany
| | - Daniel Stopper
- Institute for Theoretical Physics, University of Tübingen, 72076 Tübingen, Germany
| | - Michal K Braun
- Institute for Applied Physics, University of Tübingen, 72076 Tübingen, Germany
| | | | - Fajun Zhang
- Institute for Applied Physics, University of Tübingen, 72076 Tübingen, Germany
| | - Robert M J Jacobs
- Department for Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, United Kingdom
| | | | - Hendrik Hansen-Goos
- Institute for Theoretical Physics, University of Tübingen, 72076 Tübingen, Germany
| | - Roland Roth
- Institute for Theoretical Physics, University of Tübingen, 72076 Tübingen, Germany
| | - Frank Schreiber
- Institute for Applied Physics, University of Tübingen, 72076 Tübingen, Germany
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15
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Schoch RL, Emilsson G, Dahlin AB, Lim RY. Protein exclusion is preserved by temperature sensitive PEG brushes. POLYMER 2017. [DOI: 10.1016/j.polymer.2017.10.063] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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16
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Rother G, Müter D, Bock H, Schoen M, Findenegg GH. From aggregative adsorption to surface depletion: aqueous systems of CnEm amphiphiles at hydrophilic surfaces. Mol Phys 2017. [DOI: 10.1080/00268976.2017.1299234] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Gernot Rother
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Institut für Chemie, Technische Universität Berlin, Berlin, Germany
- Geochemistry & Interfacial Science Group, Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Dirk Müter
- Nano-Science Center, Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - Henry Bock
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh, United Kingdom
| | - Martin Schoen
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Institut für Chemie, Technische Universität Berlin, Berlin, Germany
| | - Gerhard H. Findenegg
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Institut für Chemie, Technische Universität Berlin, Berlin, Germany
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17
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de Ghellinck A, Fragneto G, Laux V, Haertlein M, Jouhet J, Sferrazza M, Wacklin H. Lipid polyunsaturation determines the extent of membrane structural changes induced by Amphotericin B in Pichia pastoris yeast. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:2317-25. [PMID: 26055896 DOI: 10.1016/j.bbamem.2015.06.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 05/20/2015] [Accepted: 06/04/2015] [Indexed: 12/18/2022]
Abstract
The activity of the potent but highly toxic antifungal drug Amphotericin B (AmB), used intravenously to treat systemic fungal and parasitic infections, is widely accepted to result from its specific interaction with the fungal sterol ergosterol. While the effect of sterols on AmB activity has been intensely investigated, the role of membrane phospholipid composition has largely been ignored, and structural studies of native membranes have been hampered by their complex and disordered nature. We show for the first time that the structure of fungal membranes derived from Pichia pastoris yeast depends on the degree of lipid polyunsaturation, which has an impact on the structural consequences of AmB activity. AmB inserts in yeast membranes even in the absence of ergosterol, and forms an extra-membraneous layer whose thickness is resolved to be 4-5 nm. In ergosterol-containing membranes, AmB insertion is accompanied by ergosterol extraction into this layer. The AmB-sponge mediated depletion of ergosterol from P. pastoris membranes gives rise to a significant membrane thinning effect that depends on the degree of lipid polyunsaturation. The resulting hydrophobic mismatch is likely to interfere with a much broader range of membrane protein functions than those directly involving ergosterol, and suggests that polyunsaturated lipids could boost the efficiency of AmB. Furthermore, a low degree of lipid polyunsaturation leads to least AmB insertion and may protect host cells against the toxic effects of AmB. These results provide a new framework based on lipid composition and membrane structure through which we can understand its antifungal action and develop better treatments.
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Affiliation(s)
- Alexis de Ghellinck
- Institut Laue-Langevin, 71 av des Martyrs, P.O. Box 156, 38000 Grenoble, France; Departement de Physique, Faculté des Sciences, Université Libre de Bruxelles, Bd du Triomphe CP223, 1050 Bruxelles, Belgium
| | - Giovanna Fragneto
- Institut Laue-Langevin, 71 av des Martyrs, P.O. Box 156, 38000 Grenoble, France
| | - Valerie Laux
- Institut Laue-Langevin, 71 av des Martyrs, P.O. Box 156, 38000 Grenoble, France
| | - Michael Haertlein
- Institut Laue-Langevin, 71 av des Martyrs, P.O. Box 156, 38000 Grenoble, France
| | - Juliette Jouhet
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS/CEA/Univ. Grenoble Alpes/INRA, 38000 Grenoble, France
| | - Michele Sferrazza
- Departement de Physique, Faculté des Sciences, Université Libre de Bruxelles, Bd du Triomphe CP223, 1050 Bruxelles, Belgium
| | - Hanna Wacklin
- European Spallation Source ESS AB, P.O. Box 176, 22100 Lund, Sweden; Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark.
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18
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Johnson PS, Goel M, Abbott NL, Himpsel FJ. Helical versus all-trans conformations of oligo(ethylene glycol)-terminated alkanethiol self-assembled monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:10263-10269. [PMID: 25133805 DOI: 10.1021/la500978s] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The complex mixture of conformational states exhibited by oligo(ethylene glycol)-terminated alkanethiols on Ag and Au surfaces is explored by polarization-dependent X-ray absorption spectroscopy. Three self-assembled monolayers (SAMs) with known helical or all-trans conformations are used as references to characterize a SAM with unknown conformations. This case study is used as a prototype for developing a systematic framework to extract the conformations of SAMs from the polarization dependence of several orbitals. In the case at hand, these are associated with the C-H/Rydberg bonds of the alkane, the C-H/Rydberg bonds of ethylene glycol, and the C-C bonds of the backbone. The C-H/Rydberg orbitals of the alkane and ethylene glycol are distinguished via the chemical shift of the corresponding C 1s core levels.
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Affiliation(s)
- Phillip S Johnson
- Department of Physics, University of Wisconsin-Madison , 1150 University Avenue, Madison, Wisconsin 53706, United States
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Inada N, Asakawa H, Matsumoto Y, Fukuma T. Molecular-scale surface structures of oligo(ethylene glycol)-terminated self-assembled monolayers investigated by frequency modulation atomic force microscopy in aqueous solution. NANOTECHNOLOGY 2014; 25:305602. [PMID: 25008429 DOI: 10.1088/0957-4484/25/30/305602] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The structure and protein resistance of oligo(ethylene glycol)-terminated self-assembled monolayers (OEG-SAMs) have been studied intensively using various techniques. However, their molecular-scale surface structures have not been well understood. In this study, we performed molecular-resolution imaging of OH-terminated SAMs (OH-SAMs) and hexa(ethylene glycol) SAMs (EG(6)OH-SAMs) formed on a Au(111) surface in an aqueous solution by frequency modulation atomic force microscopy (FM-AFM). The results show that most of the ethylene glycol (EG) chains in an EG(6)OH-SAM are closely packed and well-ordered to present a molecularly flat surface even in an aqueous solution. In addition, we found that EG(6)OH-SAMs have nanoscale defects, where molecules take a disordered arrangement with their molecular axes parallel to the substrate surface. We also found that the domain size (50-200 nm) of an EG(6)OH-SAM is much larger than that of OH-SAMs (10-40 nm). These findings should significantly advance molecular-scale understanding about the surface structure of OEG-SAMs.
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Affiliation(s)
- N Inada
- Division of Electrical Engineering and Computer Science, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
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Schollbach M, Zhang F, Roosen-Runge F, Skoda MWA, Jacobs RMJ, Schreiber F. Gold nanoparticles decorated with oligo(ethylene glycol) thiols: surface charges and interactions with proteins in solution. J Colloid Interface Sci 2014; 426:31-8. [PMID: 24863761 DOI: 10.1016/j.jcis.2014.03.052] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 03/24/2014] [Accepted: 03/25/2014] [Indexed: 11/30/2022]
Abstract
We have studied oligo(ethylene glycol) (OEG) thiol self-assembled monolayer (SAM) coated gold nanoparticles (AuOEG) and their interactions with proteins in solutions using electrophoretic and dynamic light scattering (ELS and DLS). The results are compared with poly(ethylene glycol) (PEG) thiol coated AuNPs (AuPEG). We show that both AuOEG and AuPEG particles carry a low net negative charge and are very stable (remaining so for more than one year), but long-term aging or dialysis can reduce the stability. If the decorated AuNPs are mixed with bovine serum albumin (BSA), both effective size and zeta-potential of the AuNPs remain unchanged, indicating no adsorption of BSA to the colloid surface. However, when mixed with lysozyme, zeta-potential values increase with protein concentrations and lead to a charge inversion, indicating adsorption of lysozyme to the colloid surface. The colloidal solutions of AuOEG become unstable near zero charge, indicated by a cluster peak in the DLS measurements. The AuPEG solutions show similar charge inversion upon addition of lysozyme, but the solutions are stable under all experimental conditions, presumably because of the strong steric effect of PEG. Washing the protein bound colloids by centrifugation can remove only part of the adsorbed lysozyme molecules indicating that a few proteins adsorb strongly to the colloids. The effective charge inversion and rather strongly bound lysozyme on the colloid surface may suggest that in addition to the charges formed at the SAM-water interface, there are defects on the surface of the colloid, which are accessible to the proteins. The results of this study of surface charge, and stability shed light on the interaction with proteins of SAM coated AuNPs and their applications.
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Affiliation(s)
- Moritz Schollbach
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, D-72076 Tübingen, Germany
| | - Fajun Zhang
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, D-72076 Tübingen, Germany.
| | - Felix Roosen-Runge
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, D-72076 Tübingen, Germany
| | - Maximilian W A Skoda
- STFC, ISIS, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0OX, United Kingdom
| | - Robert M J Jacobs
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road OX1 3TA, United Kingdom
| | - Frank Schreiber
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, D-72076 Tübingen, Germany
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Yang S, Wang B, Cui D, Kerwood D, Wilkens S, Han J, Luk YY. Stereochemical Control of Nonamphiphilic Lyotropic Liquid Crystals: Chiral Nematic Phase of Assemblies Separated by Six Nanometers of Aqueous Solvents. J Phys Chem B 2013; 117:7133-43. [DOI: 10.1021/jp401382h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Sijie Yang
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, United
States
| | - Bing Wang
- Novartis Institutes for BioMedical Research, Inc., Cambridge, Massachusetts
02139, United States
| | - Dawei Cui
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, United
States
| | - Deborah Kerwood
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, United
States
| | - Stephan Wilkens
- Department
of Biochemistry and
Molecular Biology, Upstate Medical University, State University of New York, Syracuse, New York 13210, United
States
| | - Junjie Han
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, United
States
| | - Yan-Yeung Luk
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, United
States
- Department of Biomedical
and
Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
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22
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Fairman C, Ginges JZ, Lowe SB, Gooding JJ. Protein Resistance of Surfaces Modified with Oligo(Ethylene Glycol) Aryl Diazonium Derivatives. Chemphyschem 2013; 14:2183-9. [DOI: 10.1002/cphc.201300040] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Indexed: 11/06/2022]
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Richter AG, Kuzmenko I. Using in situ X-ray reflectivity to study protein adsorption on hydrophilic and hydrophobic surfaces: benefits and limitations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:5167-5180. [PMID: 23586436 DOI: 10.1021/la3049532] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We have employed in situ X-ray reflectivity (IXRR) to study the adsorption of a variety of proteins (lysozyme, cytochrome c, myoglobin, hemoglobin, serum albumin, and immunoglobulin G) on model hydrophilic (silicon oxide) and hydrophobic surfaces (octadecyltrichlorosilane self-assembled monolayers), evaluating this recently developed technique for its applicability in the area of biomolecular studies. We report herein the highest resolution depiction of adsorbed protein films, greatly improving on the precision of previous neutron reflectivity (NR) results and previous IXRR studies. We were able to perform complete scans in 5 min or less with the maximum momentum transfer of at least 0.52 Å(-1), allowing for some time-resolved information about the evolution of the protein film structure. The three smallest proteins (lysozyme, cytochrome c, and myoglobin) were seen to deposit as fully hydrated, nondenatured molecules onto hydrophilic surfaces, with indications of particular preferential orientations. Time evolution was observed for both lysozyme and myoglobin films. The larger proteins were not observed to deposit on the hydrophilic substrates, perhaps because of contrast limitations. On hydrophobic surfaces, all proteins were seen to denature extensively in a qualitatively similar way but with a rough trend that the larger proteins resulted in lower coverage. We have generated high-resolution electron density profiles of these denatured films, including capturing the growth of a lysozyme film. Because the solution interface of these denatured films is diffuse, IXRR cannot unambiguously determine the film extent and coverage, a drawback compared to NR. X-ray radiation damage was systematically evaluated, including the controlled exposure of protein films to high-intensity X-rays and exposure of the hydrophobic surface to X-rays before adsorption. Our analysis showed that standard measuring procedures used for XRR studies may lead to altered protein films; therefore, we used modified procedures to limit the influence of X-ray damage.
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Affiliation(s)
- Andrew G Richter
- Department of Physics and Astronomy, Valparaiso University, Valparaiso, Indiana 46383, USA.
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Tarasevich BJ, Perez-Salas U, Masica DL, Philo J, Kienzle P, Krueger S, Majkrzak CF, Gray JL, Shaw WJ. Neutron reflectometry studies of the adsorbed structure of the amelogenin, LRAP. J Phys Chem B 2013; 117:3098-109. [PMID: 23477285 PMCID: PMC3634335 DOI: 10.1021/jp311936j] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Amelogenins make up over 90% of the protein present during enamel formation and have been demonstrated to be critical in proper enamel development, but the mechanism governing this control is not well understood. Leucine-rich amelogenin peptide (LRAP) is a 59-residue splice variant of amelogenin and contains the charged regions from the full protein thought to control crystal regulation. In this work, we utilized neutron reflectivity (NR) to investigate the structure and orientation of LRAP adsorbed from solutions onto molecularly smooth COOH-terminated self-assembled monolayer (SAM) surfaces. Sedimentation velocity (SV) experiments revealed that LRAP is primarily a monomer in saturated calcium phosphate (SCP) solutions (0.15 M NaCl) at pH 7.4. LRAP adsorbed as ∼32 Å thick layers at ∼70% coverage as determined by NR. Rosetta simulations of the dimensions of LRAP in solution (37 Å diameter) indicate that the NR determined z dimension is consistent with an LRAP monomer. SV experiments and Rosetta simulations show that the LRAP monomer has an extended, asymmetric shape in solution. The NR data suggests that the protein is not completely extended on the surface, having some degree of structure away from the surface. A protein orientation with the C-terminal and inner N-terminal regions (residues ∼8-24) located near the surface is consistent with the higher scattering length density (SLD) found near the surface by NR. This work presents new information on the tertiary and quaternary structure of LRAP in solution and adsorbed onto surfaces. It also presents further evidence that the monomeric species may be an important functional form of amelogenin proteins.
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Affiliation(s)
- Barbara J Tarasevich
- Pacific Northwest National Laboratory, Richland, Washington 99354, United States.
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26
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Couston RG, Skoda MW, Uddin S, van der Walle CF. Adsorption behavior of a human monoclonal antibody at hydrophilic and hydrophobic surfaces. MAbs 2012. [PMID: 23196810 DOI: 10.4161/mabs.22522] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
One aspiration for the formulation of human monoclonal antibodies (mAb) is to reach high solution concentrations without compromising stability. Protein surface activity leading to instability is well known, but our understanding of mAb adsorption to the solid-liquid interface in relevant pH and surfactant conditions is incomplete. To investigate these conditions, we used total internal reflection fluorescence (TIRF) and neutron reflectometry (NR). The mAb tested ("mAb-1") showed highest surface loading to silica at pH 7.4 (~12 mg/m(2)), with lower surface loading at pH 5.5 (~5.5 mg/m(2), further from its pI of 8.99) and to hydrophobized silica (~2 mg/m(2)). The extent of desorption of mAb-1 from silica or hydrophobized silica was related to the relative affinity of polysorbate 20 or 80 for the same surface. mAb-1 adsorbed to silica on co-injection with polysorbate (above its critical micelle concentration) and also to silica pre-coated with polysorbate. A bilayer model was developed from NR data for mAb-1 at concentrations of 50-5000 mg/L, pH 5.5, and 50-2000 mg/L, pH 7.4. The inner mAb-1 layer was adsorbed to the SiO₂ surface at near saturation with an end-on" orientation, while the outer mAb-1 layer was sparse and molecules had a "side-on" orientation. A non-uniform triple layer was observed at 5000 mg/L, pH 7.4, suggesting mAb-1 adsorbed to the SiO₂ surface as oligomers at this concentration and pH. mAb-1 adsorbed as a sparse monolayer to hydrophobized silica, with a layer thickness increasing with bulk concentration - suggesting a near end-on orientation without observable relaxation-unfolding.
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Affiliation(s)
- Ruairidh G Couston
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, Scotland, UK
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27
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Couston RG, Lamprou DA, Uddin S, van der Walle CF. Interaction and destabilization of a monoclonal antibody and albumin to surfaces of varying functionality and hydrophobicity. Int J Pharm 2012; 438:71-80. [DOI: 10.1016/j.ijpharm.2012.09.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 08/30/2012] [Accepted: 09/01/2012] [Indexed: 01/31/2023]
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Akkahat P, Kiatkamjornwong S, Yusa SI, Hoven VP, Iwasaki Y. Development of a novel antifouling platform for biosensing probe immobilization from methacryloyloxyethyl phosphorylcholine-containing copolymer brushes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:5872-5881. [PMID: 22364521 DOI: 10.1021/la204229t] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The immobilization of thiol-terminated poly[(methacrylic acid)-ran-(2-methacryloyloxyethyl phosphorylcholine)] (PMAMPC-SH) brushes on gold-coated surface plasmon resonance (SPR) chips was performed using the "grafting to" approach via self-assembly formation. The copolymer brushes provide both functionalizability and antifouling characteristics, desirable features mandatorily required for the development of an effective platform for probe immobilization in biosensing applications. The carboxyl groups from the methacrylic acid (MA) units were employed for attaching active biomolecules that can act as sensing probes for biospecific detection of target molecules, whereas the 2-methacryloyloxyethyl phosphorylcholine (MPC) units were introduced to suppress unwanted nonspecific adsorption. The detection efficiency of the biotin-immobilized PMAMPC brushes with the target molecule, avidin (AVD), was evaluated in blood plasma in comparison with the conventional 2D monolayer of 11-mercaptoundecanoic acid (MUA) and homopolymer brushes of poly(methacrylic acid) (PMA) also immobilized with biotin using the SPR technique. Copolymer brushes with 79 mol % MPC composition and a molecular weight of 49.3 kDa yielded the platform for probe immobilization with the best performance considering its high S/N ratio as compared with platforms based on MUA and PMA brushes. In addition, the detection limit for detecting AVD in blood plasma solution was found to be 1.5 nM (equivalent to 100 ng/mL). The results have demonstrated the potential for using these newly developed surface-attached PMAMPC brushes for probe immobilization and subsequent detection of designated target molecules in complex matrices such as blood plasma and clinical samples.
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Affiliation(s)
- Piyaporn Akkahat
- Program in Petrochemistry, Faculty of Science, Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand
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Nonfouling polyampholyte polymer brushes with protein conjugation capacity. Colloids Surf B Biointerfaces 2012; 93:195-201. [PMID: 22277745 DOI: 10.1016/j.colsurfb.2012.01.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 12/06/2011] [Accepted: 01/04/2012] [Indexed: 01/18/2023]
Abstract
The elimination of nonspecific protein adsorption is an important challenge in many biomaterial applications. To address this issue, numerous nonfouling chemistries have been investigated. This work reports on the dual functional properties of a polyampholyte copolymer composed of positively charged [2-(acryloyloxy) ethyl] trimethyl ammonium chloride (TMA) and negatively charged 2-carboxy ethyl acrylate (CAA) monomers. TMA:CAA copolymers have previously been shown to have nonfouling properties, but the optimal conditions for nonfouling have not been determined. To accomplish this, the thickness of the polymer brush coating was varied by manipulating the surface-initiated atom transfer radical polymerization conditions. The nonspecific adsorption of fibrinogen and lysozyme was measured as a function of the copolymer brush thickness using a surface plasmon resonance biosensor. At the optimal thickness for nonfouling, nonspecific adsorption from 10% and 100% fetal bovine serum (FBS) was determined. The results indicate that at the optimal copolymer brush thickness, TMA:CAA polyampholyte materials have ultralow fouling characteristics even upon exposure to 100% FBS. The dual functional properties of TMA:CAA copolymers were demonstrated by conjugating fibrinogen to the copolymer brush over a range of brush thicknesses. The conjugation experiments clearly demonstrate that TMA:CAA copolymers have the capacity for protein conjugation at the optimal thickness for nonfouling. However, the conformational state of the copolymer brush chains impacts the overall conjugation capacity of the system. The results of this investigation indicate that TMA:CAA polyampholyte surfaces show promise for biosensor and biomaterial applications where their dual functional properties would be beneficial.
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31
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Zorn S, Skoda MWA, Gerlach A, Jacobs RMJ, Schreiber F. On the stability of oligo(ethylene glycol) (C11EG6OMe) SAMs on gold: behavior at elevated temperature in contact with water. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:2237-2243. [PMID: 21338125 DOI: 10.1021/la104132q] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In this study the temperature dependent confor-mation of hexa(ethylene glycol) self-assembling monolayers (SAMs) under aqueous conditions (in situ) is investigated. To this end characteristic absorption modes in the fingerprint region (1050-1500 cm(-1)) were monitored with real-time polarization modulation infrared spectroscopy. We found a temperature induced conformational change from predominantly helical to helical/all-trans. The process may be divided into two temperature regimes. Up to 40 °C the process is reversible after drying the monolayers in air and successive reimmersion in water, indicating a strong binding of the water molecules to the SAM. At higher temperatures, the conformational change is irreversible. Additionally, a rapid change to a larger mode width and a shift of the mode position to higher wavenumbers (blue-shift) at about 50 °C indicates structural changes caused by decreasing crystallinity of the SAM. While the conformational changes up to 40 °C are supposed to originate from an increased conformational freedom in combination with a stronger interaction with water molecules, the irreversibility and rapid change of mode characteristics at higher temperatures indicate chemical degradation. Complementary measurements in air show a fast and virtually complete reversibility up to 40 °C underlining the effect of the interaction of the ethylene glycol moiety with water. At temperatures above 50 °C modes indicating ester and formate groups appear, supporting the idea of chemical degeneration. Moreover, the temperature behavior is coverage dependent. At incomplete coverage the structural order of the SAM starts decreasing at lower temperatures. This study shows, that the conformational and structural change of hexa(ethylene glycol) SAMs at elevated temperature is an interplay of conformational changes of the SAM, its interaction with water and at higher temperatures its chemical degradation. Our experiments also underline the importance of the in situ analysis on the film structure.
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Affiliation(s)
- Stefan Zorn
- Institute for Applied Physics, Eberhard-Karls University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
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Castronovo M, Lucesoli A, Parisse P, Kurnikova A, Malhotra A, Grassi M, Grassi G, Scaggiante B, Casalis L, Scoles G. Two-dimensional enzyme diffusion in laterally confined DNA monolayers. Nat Commun 2011; 2:297. [PMID: 21540839 DOI: 10.1038/ncomms1296] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 03/30/2011] [Indexed: 02/08/2023] Open
Abstract
Addressing the effects of confinement and crowding on biomolecular function may provide insight into molecular mechanisms within living organisms, and may promote the development of novel biotechnology tools. Here, using molecular manipulation methods, we investigate restriction enzyme reactions with double-stranded (ds)DNA oligomers confined in relatively large (and flat) brushy matrices of monolayer patches of controlled, variable density. We show that enzymes from the contacting solution cannot access the dsDNAs from the top-matrix interface, and instead enter at the matrix sides to diffuse two-dimensionally in the gap between top- and bottom-matrix interfaces. This is achieved by limiting lateral access with a barrier made of high-density molecules that arrest enzyme diffusion. We put forward, as a possible explanation, a simple and general model that relates these data to the steric hindrance in the matrix, and we briefly discuss the implications and applications of this strikingly new phenomenon.
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Affiliation(s)
- Matteo Castronovo
- Department of Biology, Temple University, 1900 North 12th Street, Philadelphia, Philadelphia 19122, USA.
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Zorn S, Martin N, Gerlach A, Schreiber F. Real-time PMIRRAS studies of in situ growth of C11Eg6OMe on gold and immersion effects. Phys Chem Chem Phys 2010; 12:8985-90. [PMID: 20532327 DOI: 10.1039/b923691k] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We studied the growth of self-assembling monolayers of C(11)Eg(6)OMe on gold under aqueous conditions. With the help of polarisation modulation infrared reflection absorption spectroscopy (PMIRRAS) we monitored the evolution of characteristic absorption modes in the fingerprint region (1050-1500 cm(-1)) during the later stages of the growth of the SAM. We observed a change from rather amorphous structure with mixed all-trans and helical conformation to an ordered structure with predominantly helical structure over time. Changes of mode positions, intensities and broadness can be described by a single exponential. In addition, we investigated the effect of hydration for SAMs with different degrees of crystallinity. To that end, we compared their spectra at certain ordering levels in contact with aqueous solution with the corresponding spectra in air. SAMs with a highly ordered crystalline structure in air show the same structure under aqueous conditions. However, SAMs which are still crystalline in air, but less perfect, show rather amorphous spectral features under aqueous conditions indicating a strong interaction with water. This implies that the ability of water to penetrate the EG moiety strongly depends on its structure which in turn is related inter alia to the surface coverage. Since the interaction with water plays an important role in the prevention of unspecific adsorption on oligo(ethylene glycols) this is important for its application. Our experiments also underline the importance of the in situ analysis of the film structure.
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Affiliation(s)
- Stefan Zorn
- Institute for Applied Physics, Eberhard-Karls University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
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35
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Protein immobilization at gold–thiol surfaces and potential for biosensing. Anal Bioanal Chem 2010; 398:1545-64. [DOI: 10.1007/s00216-010-3708-6] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Revised: 03/29/2010] [Accepted: 03/30/2010] [Indexed: 12/14/2022]
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Rosenhahn A, Schilp S, Kreuzer HJ, Grunze M. The role of "inert" surface chemistry in marine biofouling prevention. Phys Chem Chem Phys 2010; 12:4275-86. [PMID: 20407695 DOI: 10.1039/c001968m] [Citation(s) in RCA: 190] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The settlement and colonization of marine organisms on submerged man-made surfaces is a major economic problem for many marine industries. The most apparent detrimental effects of biofouling are increased fuel consumption of ships, clogging of membranes and heat exchangers, disabled underwater sensors, and growth of biofoulers in aquaculture systems. The presently common-but environmentally very problematic-way to deal with marine biofouling is to incorporate biocides, which use biocidal products in the surface coatings to kill the colonizing organisms, into the surface coatings. Since the implementation of the International Maritime Organization Treaty on biocides in 2008, the use of tributyltin (TBT) is restricted and thus environmentally benign but effective surface coatings are required. In this short review, we summarize the different strategies which are pursued in academia and industry to better understand the mechanisms of biofouling and to develop strategies which can be used for industrial products. Our focus will be on chemically "inert" model surface coatings, in particular oligo- and poly(ethylene glycol) (OEG and PEG) functionalized surface films. The reasons for choosing this class of chemistry as an example are three-fold: Firstly, experiments on spore settlement on OEG and PEG coatings help to understand the mechanism of non-fouling of highly hydrated interfaces; secondly, these studies defy the common assumption that surface hydrophilicity-as measured by water contact angles-is an unambiguous and predictive tool to determine the fouling behavior on the surface; and thirdly, choosing this system is a good example for "interfacial systems chemistry": it connects the behavior of unicellular marine organisms with the antifouling properties of a hydrated surface coating with structural and electronic properties as derived from ab initio quantum mechanical calculations using the electronic wave functions of oxygen, hydrogen, and carbon. This short review is written to outline for non-experts the hierarchical structure in length- and timescale of marine biofouling and the role of surface chemistry in fouling prevention. Experts in the field are referred to more specialized recent reviews.
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Affiliation(s)
- Axel Rosenhahn
- Applied Physical Chemistry, University of Heidelberg, 69120 Heidelberg, Germany
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Goda T, Miyahara Y. Detection of Microenvironmental Changes Induced by Protein Adsorption onto Self-Assembled Monolayers using an Extended Gate-Field Effect Transistor. Anal Chem 2010; 82:1803-10. [DOI: 10.1021/ac902401y] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tatsuro Goda
- Biomaterials Center and International Center for Materials and Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Yuji Miyahara
- Biomaterials Center and International Center for Materials and Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
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Bonnet N, O'Hagan D, Hähner G. Protein adsorption onto CF3-terminated oligo(ethylene glycol) containing self-assembled monolayers (SAMs): the influence of ionic strength and electrostatic forces. Phys Chem Chem Phys 2010; 12:4367-74. [DOI: 10.1039/b923065n] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Christophis C, Grunze M, Rosenhahn A. Quantification of the adhesion strength of fibroblast cells on ethylene glycol terminated self-assembled monolayers by a microfluidic shear force assay. Phys Chem Chem Phys 2010; 12:4498-504. [DOI: 10.1039/b924304f] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Schilp S, Rosenhahn A, Pettitt ME, Bowen J, Callow ME, Callow JA, Grunze M. Physicochemical properties of (ethylene glycol)-containing self-assembled monolayers relevant for protein and algal cell resistance. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:10077-10082. [PMID: 19469528 DOI: 10.1021/la901038g] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The influence of the number of repeating units in self-assembled monolayers (SAMs) of ethylene glycol and of their end-group termination on the settlement and adhesion of two types of algal cells, viz., zoospores of the macroalga Ulva and cells of the diatom Navicula , was studied. The findings are related to the resistance of these surfaces against fibrinogen adsorption. Results showed that settlement and adhesion of algal cells to oligo(ethylene glycol) (OEG; 2-6 EG units) and poly(ethylene glycol) (PEG; MW = 2000, 5000) SAMs was low, while resistance was less effective for mono(ethylene glycol) (EG(1)OH)-terminated surfaces. These findings concur with former protein adsorption studies. In situ microscopy showed that PEG surfaces inhibited the settlement of zoospores, i.e., zoospores did not attach to the surfaces and remained motile. In contrast, on EG(2-6)OH surfaces, although zoospores settled, i.e., they secreted adhesive and lost motility, adhesion between secreted adhesive and the surface was extremely weak, and the settled spores were unable to bond to the surfaces. The influence of surface properties such as hydration, conformational degrees of freedom, and interfacial characteristics of the SAMs is discussed to understand the underlying repulsive mechanisms occurring in (ethylene glycol)-based coatings.
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Affiliation(s)
- Soeren Schilp
- Angewandte Physikalische Chemie, Universitat Heidelberg, INF 253, 69120 Heidelberg, Germany
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