Pult H.,Optometry and Vision Research |
Pult H.,University of Cardiff |
Pult H.,Aston University |
Tosatti S.G.P.,SuSoS AG |
And 4 more authors.
Ocular Surface | Year: 2015
The mechanical forces between the lid wiper and the ocular surface, and between a contact lens and the lid wiper, are reported to be related to dry eye symptoms. Furthermore, the mechanical forces between these sliding partners are assumed to be related to the ocular signs of lid-wiper epitheliopathy (LWE) and lid-parallel conjunctival folds (LIPCOF). Recent literature provides some evidence that a contact lens with a low coefficient of friction (CoF) improves wearing comfort by reducing the mechanical forces between the contact lens surface and the lid wiper. This review discusses the mechanical forces during spontaneous blinks from a tribological perspective, at both low and high sliding velocities, in a healthy subject. It concludes that the coefficient of friction of the ocular surfaces appears to be strongly comparable to that of hydrophilic polymer brushes at low sliding velocity, and that, with increased sliding velocity, there is no wear at the sliding partners' surfaces thanks to the presence of a fluid film between the two sliding partners. In contrast, in the case of dry eye, the failure to maintain a full fluid film lubrication regime at high blinking speeds may lead to increased shear rates, resulting in deformation and wear of the sliding pairs. These shear rates are most likely related to tear film viscosity. © 2015 Elsevier Inc.
Bozzini S.,Polytechnic of Milan |
Bozzini S.,ETH Zurich |
Petrini P.,Polytechnic of Milan |
Tanzi M.C.,Polytechnic of Milan |
And 4 more authors.
Langmuir | Year: 2010
The spontaneous formation of alkane phosphate self-assembled monolayers (SAMs) on titanium oxide was chosen as a tool to tailor the surface physicochemical properties in terms of nonspecific adsorption of proteins. For this aim, poly(ethylene glycol)-modified (PEG) alkane phosphate was codeposited with OH-terminated alkane phosphates. X-ray photoelectron spectroscopy and ellipsometry of the resulting mixed SAMs indicate that the PEG density can be controlled by varying the mole fraction of PEG-terminated phosphates in the solutions used during the deposition process, leading to surfaces with different degrees of protein resistance. © 2009 American Chemical Society.
Agency: European Commission | Branch: FP7 | Program: MC-ITN | Phase: FP7-PEOPLE-ITN-2008 | Award Amount: 3.28M | Year: 2010
The main research goal of SEACOAT is to improve understanding of biointerfacial processes involved in the colonisation of surfaces by marine fouling organisms. Our vision is that this enhanced understanding will inform the future development of new, environmentally-benign materials and coatings for the practical control of marine biofouling. Our principal objective is to discover which nano- and micro-scale physico-chemical properties of surfaces influence the adhesion of fouling organisms, through the use of surface engineering technologies to fabricate coatings that vary systematically in relevant surface properties, and length scales. We will use advanced surface analytical methods to characterise test surfaces for relevant physico-chemical surface properties and how these change after immersion. Parallel adhesion bioassays using a range of representative marine organisms will test intrinsic antifouling properties of surfaces. The network is an interdisciplinary cooperative of chemists, physicists and marine biologists. Intersectoral aspects unite basic and applied scientists working in universities, a large company and an SME. The projects S&T objectives will be delivered through research in 4 main Work Packages: viz. WP1-Surface Engineering, WP2-Surface Analytics, WP3-Bioadhesion, WP4- Integration. Two additional Work Packages (WP5, WP6) will be concerned with the Dissemination of project results and the Management of the Network respectively. The aim of the Training Programme is to increase the knowledge base and experience of trainees in each of the Thematic Areas and to develop their transferable skills for future careers in industry or academia. Six training objectives will be delivered through a suite of 7 Core Skills Areas (Research Project, Advanced Training Courses, Project Conferences, International Winter Workshop, Career Development Plan, Generic Research Skills, Transferable Research Skills).
Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: NMP-2007-1.1-1 | Award Amount: 5.44M | Year: 2008
More than 50% of all drug targets are membrane proteins; new research tools to screen function of membrane drug targets are therefore expected to open up new avenues for original drug development. The proposed project addresses the need of the pharmaceutical industry for new technologies for reliable and efficient screening of membrane proteins as drug targets. Most critical current aspects of membrane protein assays are (a) the lack of reliable procedures to immobilize membrane proteins on sensor surfaces in a format suitable for label-free high-throughput screening of drug candidates; (b) the need for downscaling assay formats to accelerate functional screening; and (c) the feasibility of reading out the diverse functions of membrane proteins. The partners with highly complementary expertise and experience of working together will develop platforms for functional membrane protein assays by integration of the most recently gained knowledge and techniques. The key concepts of the platforms include (a) exploitation of nanoporous substrates to enhance the stability of supported proteolipid membranes and their integration in a sensor chip format; (b) nanoscale surface modifications for directed self-assembly of proteolipid structures on chip; and (c) self-assembly of proteolipid membranes onto nano-sized sensor structures from proteoliposomes, and demonstration of the functionality in quantitative drug candidate screening assays suitable for commercial applications. The project is expected to make a substantial contribution to (a) improved understanding of lipid membrane and membrane protein interaction with designed nanoenvironments; (b) development of prototype products and intellectual property related to membrane protein sorting and handling; (c) new compounds for functionalization of biosensor applications; (d) cost-effective array-based concepts for nanoplasmonic and electrochemical sensing; and (e) functional assays for membrane protein drug targets.
Serrano A.,ETH Zurich |
Serrano A.,SuSoS AG |
Sterner O.,ETH Zurich |
Mieszkin S.,University of Birmingham |
And 7 more authors.
Advanced Functional Materials | Year: 2013
Polymeric ultrathin films present a possible line of attack against marine biofouling for some applications. A protocol that provides a reliable comparison of the resistance of different polymers to biofouling is described. This is achieved through the use of a common, azide-terminated adhesion monolayer, to which different nonfouling polymers of various molecular weights, specifically poly(ethylene glycol) (PEG), poly(2-ethyl-2-oxazoline) (PEOXA), poly(vinyl pyrrolidone) (PVP), poly(vinyl alcohol) (PVA), and dextran are covalently bound. These functionalized surfaces are characterized by dynamic contact angle, ellipsometry, and X-ray photoelectron spectroscopy (XPS). To validate the developed protocol and evaluate performance against a selection of well-known, marine-fouling organisms, the nonfouling surfaces are subjected to a comparative biological study by exposure to a complex protein solution (with characterization via ellipsometry and quartz crystal microbalance with dissipation (QCM-D)), marine bacteria (Cobetia marina and Marinobacter hydrocarbonoclasticus), and zoospores of the green alga Ulva linza. The resulting data are used to draw conclusions on structure-property relationships. Chemical resistance towards marine fouling can be achieved using the described immobilization method, but is highly dependent on the species tested. Findings show that PVP (55 kDa)-coated surfaces display consistent resistance towards all tested solutions and organisms and, hence, this polymer could be considered as a potential material for marine-nonfouling applications. Surface functionalization with 5 different hydrophilic uncharged polymers, their characterization, and a direct comparison of their resistance against biofouling are achieved by means of a photochemical grafting method using a perfluorophenylazide (PFPA)-based adhesion promoter. The fouling response is determined on different length scales from proteins to cells (nano- to micrometer for proteins and bacteria/spores, respectively). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Spori D.M.,ETH Zurich |
Drobek T.,Ludwig Maximilians University of Munich |
Zurcher S.,ETH Zurich |
Zurcher S.,SuSoS AG |
Spencer N.D.,ETH Zurich
Langmuir | Year: 2010
The superhydrophobicity of rough surfaces owes its existence to heterogeneous wetting. To investigate this phenomenon, density gradients of randomly placed holes and pillars have been fabricated by means of photolithography. On such surfaces, drops can be observed in the Cassie state over the full range of f1 (fraction of the drop's footprint area in contact with the solid). The gradient was produced with four different surface chemistries: native PDMS (polydimethylsiloxane), perfluorosilanized PDMS, epoxy, and CH3-terminated thiols on gold. It was found that f1 is the key parameter influencing the static water contact angle. Advancing and receding contact angles at any given position on the gradient are sensitive to the type of surface feature-hole or pillar-that is prevalent. In addition, roll-off angles have been measured and found to be influenced not only by the drop weight but also by suction events, edge pinning, and f1. © 2010 American Chemical Society.
Rodenstein M.,ETH Zurich |
Zurcher S.,ETH Zurich |
Zurcher S.,SuSoS AG |
Tosatti S.G.P.,ETH Zurich |
And 2 more authors.
Langmuir | Year: 2010
Catechols bind strongly to several metal oxides and can thus be used as a binding group for generating self-assembled monolayers. Furthermore, their derivatives can be used to produce well-defined, centimeter-scale surface-chemical gradients on technologically relevant surfaces, such as titanium dioxide (TiO 2). A simple dip-and-rinse gradient-preparation technique was utilized to produce surface-hydrophobicity gradients from perfluoro-alkyl catechols and nitrodopamine (ND). Chemical composition, quality, and properties of the functionalized surfaces were determined by means of X-ray photoelectron spectroscopy (XPS), variable-angle spectroscopic ellipsometry (VASE), and static water contact angle (sCA) measurements. Contact angles were found to be in the range of 30°-95°, correlating well with the determined surface chemical composition and adlayer thickness. © 2010 American Chemical Society.
Wilson T.,Johnson and Johnson Vision Care Inc |
Aeschlimann R.,SuSoS AG |
Tosatti S.,SuSoS AG |
Toubouti Y.,Johnson and Johnson Vision Care Inc |
And 2 more authors.
Cornea | Year: 2015
Purpose: A novel property evaluation methodology was used to determine the elusive value for the human corneal coefficient of friction (CoF). Methods: Using a microtribometer on 28 fresh human donor corneas with intact epithelia, the CoF was determined in 4 test solutions (≥5 corneas/solution): tear-mimicking solution (TMS) in borate-buffered saline (TMS-PS), TMS in phosphate-buffered saline (TMS-PBS), TMS with HEPES-buffered saline (TMS-HEPES), and tear-like fluid in PBS (TLF-PBS). Results: Mean (SD) CoF values ranged from 0.006 to 0.015 and were 0.013 (0.010) in TMS-PS, 0.006 (0.003) in TMS-PBS, 0.014 (0.005) in TMS-HEPES, and 0.015 (0.009) in TLF-PBS. Statistically significant differences were shown for TMS-PBS versus TLF (P 0.0424) and TMS-PBS versus TMS-HEPES (P 0.0179), but not for TMS-PBS versus TMS-PS (P 0.2389). Conclusions: Successful measurement of the fresh human corneal tissue CoF was demonstrated, with values differing in the evaluated buffer solutions, within this limited sample size. © Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Susos Ag and Rolex S.A. | Date: 2011-12-12
The invention relates to a novel ultra-thin hydrophobic and oleophobic layer, formed by self-assembly on a solid substrate surface, of compounds of the general formula A-B in which A represents a group of the formula
SuSoS AG | Date: 2010-10-06
The present invention provides a functionalized macromolecule and a composition comprising said functionalized macromolecule, which is suitable for use as an adhesion promoter. The functionalized macromolecule comprises a polymeric core, which comprises a natural, semi-synthetic or synthetic polymer, and at least two functionalized side chains, which are linked to the polymeric core by a linker group. The functionalized side chains comprise a photoreactive group.