title: Poly(oxyethylene) based surface coatings for poly(dimethylsiloxane) microchannels.
abstract: Control of surface properties in microfluidic systems is an indispensable prerequisite for successful bioanalytical applications. Poly(dimethylsiloxane) (PDMS) microfluidic devices are hampered from unwanted adsorption of biomolecules and lack of methods to control electroosmotic flow (EOF). In this paper, we propose different strategies to coat PDMS surfaces with poly(oxyethylene) (POE) molecules of varying chain lengths. The native PDMS surface is pretreated by exposure to UV irradiation or to an oxygen plasma, and the covalent linkage of POE-silanes as well as physical adsorption of a triblock-copolymer (F108) are studied. Contact angle measurements and atomic force microscopy (AFM) imaging revealed homogeneous attachment of POE-silanes and F108 to the PDMS surfaces. In the case of F108, different adsorption mechanisms to hydrophilic and hydrophobic PDMS are discussed. Determination of the electroosmotic mobilities of these coatings in PDMS microchannels prove their use for electrokinetic applications in which EOF reduction is inevitable and protein adsorption has to be suppressed.
authors.affiliation: Experimental Biophysics and Applied Nanosciences, Physics Faculty, Bielefeld University, Germany.
authors.forename: Wibke
authors.initials: W
authors.lastname: Hellmich
authors.forename: Jan
authors.initials: J
authors.lastname: Regtmeier
authors.forename: Thanh Tu
authors.initials: TT
authors.lastname: Duong
authors.forename: Robert
authors.initials: R
authors.lastname: Ros
authors.forename: Dario
authors.initials: D
authors.lastname: Anselmetti
authors.forename: Alexandra
authors.initials: A
authors.lastname: Ros
mesh_terms: D000327:Adsorption; D001672:Biocompatible Materials / Q000737:chemistry*; D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D004563:Electrochemistry / Q000379:methods*; D004586:Electrophoresis; D019075:Electrophoresis, Capillary; D007700:Kinetics; D046210:Microfluidic Analytical Techniques; D018625:Microscopy, Atomic Force; D009995:Osmosis; D010100:Oxygen / Q000737:chemistry / Q000378:metabolism; D011092:Polyethylene Glycols / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry; D012828:Silicones / Q000737:chemistry*; D013499:Surface Properties; D013997:Time Factors; D014466:Ultraviolet Rays
chemical_list: D001672:Biocompatible Materials; D004129:Dimethylpolysiloxanes; D012821:Silanes; D012828:Silicones; D011092:Polyethylene Glycols; C013830:baysilon; D010100:Oxygen