title: Thickness Dependence of Bovine Serum Albumin Adsorption on Thin Thermoresponsive Poly(diethylene glycol) Methyl Ether Methacrylate Brushes by Surface Plasmon Resonance Measurements.
abstract: This study reports on the dependence of the temperature-induced changes in the properties of thin thermoresponsive poly(diethylene glycol) methyl ether methacrylate (PDEGMA) layers of end-tethered chains on polymer thickness and grafting density. PDEGMA layers with a dry ellipsometric thickness of 5-40 nm were synthesized by surface-initiated atom transfer radical polymerization on gold. To assess the temperature-induced changes, the adsorption of bovine serum albumin (BSA) was investigated systematically as a function of film thickness, temperature, and grafting density by surface plasmon resonance (SPR), complemented by wettability and quartz crystal microbalance with dissipation monitoring (QCM-D) measurements. BSA adsorption on PDEGMA brushes is shown to differ significantly above and below an apparent transition temperature. This surface transition temperature was found to depend linearly on the PDEGMA thickness and changed from 35 °C at 5 nm thickness to 48 °C at 23 nm. Similarly, a change of the grafting density enables the adjustment of this transition temperature presumably via a transition from the mushroom to the brush regime. Finally, BSA that adsorbed irreversibly on polymer brushes at temperatures above the transition temperature can be desorbed by reducing the temperature to 25 °C, underlining the reversibly switchable properties of PDEGMA brushes in response to temperature changes.
authors.affiliation: Physical Chemistry I, Department of Chemistry and Biology & Research Center of Micro and Nanochemistry and Engineering (Cμ), and ‡NRW Junior Research Group for Nanotechnology, Organic Chemistry, Department of Chemistry and Biology & Research Center of Micro and Nanochemistry and Engineering (Cμ), University of Siegen , Adolf-Reichwein-Strasse 2, 57076 Siegen, Germany.
authors.forename: Ekram
authors.initials: E
authors.lastname: Wassel
authors.affiliation: Physical Chemistry I, Department of Chemistry and Biology & Research Center of Micro and Nanochemistry and Engineering (Cμ), and ‡NRW Junior Research Group for Nanotechnology, Organic Chemistry, Department of Chemistry and Biology & Research Center of Micro and Nanochemistry and Engineering (Cμ), University of Siegen , Adolf-Reichwein-Strasse 2, 57076 Siegen, Germany.
authors.forename: Siyu
authors.initials: S
authors.lastname: Jiang
authors.affiliation: Physical Chemistry I, Department of Chemistry and Biology & Research Center of Micro and Nanochemistry and Engineering (Cμ), and ‡NRW Junior Research Group for Nanotechnology, Organic Chemistry, Department of Chemistry and Biology & Research Center of Micro and Nanochemistry and Engineering (Cμ), University of Siegen , Adolf-Reichwein-Strasse 2, 57076 Siegen, Germany.
authors.forename: Qimeng
authors.initials: Q
authors.lastname: Song
authors.affiliation: Physical Chemistry I, Department of Chemistry and Biology & Research Center of Micro and Nanochemistry and Engineering (Cμ), and ‡NRW Junior Research Group for Nanotechnology, Organic Chemistry, Department of Chemistry and Biology & Research Center of Micro and Nanochemistry and Engineering (Cμ), University of Siegen , Adolf-Reichwein-Strasse 2, 57076 Siegen, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Vogt
authors.affiliation: Physical Chemistry I, Department of Chemistry and Biology & Research Center of Micro and Nanochemistry and Engineering (Cμ), and ‡NRW Junior Research Group for Nanotechnology, Organic Chemistry, Department of Chemistry and Biology & Research Center of Micro and Nanochemistry and Engineering (Cμ), University of Siegen , Adolf-Reichwein-Strasse 2, 57076 Siegen, Germany.
authors.forename: Gilbert
authors.initials: G
authors.lastname: Nöll
authors.affiliation: Physical Chemistry I, Department of Chemistry and Biology & Research Center of Micro and Nanochemistry and Engineering (Cμ), and ‡NRW Junior Research Group for Nanotechnology, Organic Chemistry, Department of Chemistry and Biology & Research Center of Micro and Nanochemistry and Engineering (Cμ), University of Siegen , Adolf-Reichwein-Strasse 2, 57076 Siegen, Germany.
authors.forename: Sergey I
authors.initials: SI
authors.lastname: Druzhinin
authors.affiliation: Physical Chemistry I, Department of Chemistry and Biology & Research Center of Micro and Nanochemistry and Engineering (Cμ), and ‡NRW Junior Research Group for Nanotechnology, Organic Chemistry, Department of Chemistry and Biology & Research Center of Micro and Nanochemistry and Engineering (Cμ), University of Siegen , Adolf-Reichwein-Strasse 2, 57076 Siegen, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Schönherr
mesh_terms: D000327:Adsorption; D004987:Ethers / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D058525:Quartz Crystal Microbalance Techniques; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D020349:Surface Plasmon Resonance / Q000379:methods*; D013696:Temperature; D017155:Wettability
chemical_list: D004987:Ethers; D012710:Serum Albumin, Bovine; D011092:Polyethylene Glycols