Colloids and Surfaces B: Biointerfaces 88 (2011) 265–270 Contents lists available at ScienceDirect Colloids and Surfaces B: Biointerfaces jou rn al h om epage: www.elsevier.com/locate/colsurfb Photochemically prepared polysulfone/poly(ethylene glycol) amphiphilic networks and their biomolecule adsorption properties Cemil Dizman a,b , Dilek Odaci Demirkol c , Sahin Ates a,b , Lokman Torun b , Serhan Sakarya d , Suna Timur c,∗ , Yusuf Yagci a,b,∗∗ a Istanbul Technical University, Faculty of Science and Letters, Department of Chemistry, Maslak, 34469 Istanbul, Turkey b TUBITAK Marmara Research Center, Chemistry Institute, Gebze, 41470 Kocaeli, Turkey c Ege University, Faculty of Science, Biochemistry Department, Bornova, 35100 Izmir, Turkey d Department of Infectious Diseases and Clinical Microbiology, Adnan Menderes University School of Medicine, 09100 Aydin, Turkey a r t i c l e i n f o Article history: Received 19 March 2011 Received in revised form 28 June 2011 Accepted 29 June 2011 Available online 7 July 2011 Keywords: Photopolymerization Amphiphilic networks Polysulfone Bio-inertness Cell adhesion Protein adsorption a b s t r a c t Polysulfone/poly(ethylene glycol) amphiphilic networks were prepared via in situ photo-induced free radical crosslinking polymerization. First, the hydrophobic polysulfone diacrylate (PSU-DA) oligomer was synthesized by condensation polymerization and subsequent esterification processes. Then, the obtained oligomer was co-crosslinked with the hydrophilic poly(ethylene glycol) diacrylate (PEG-DA) or poly(ethylene glycol) methyl ether acrylate (PEG-MA) at different feed ratios. In the case of PEG-MA, the resulting network possessed dangling pendant hydrophilic chains on the crosslinked surface. The struc- ture and the morphology of the membranes were characterized by attenuated total reflection infrared spectroscopy (ATR-IR) and scanning electron microscopy (SEM). The enhancement of surface hydrophilic- ity was investigated by water contact angle measurements. The biomolecule adsorption properties of these networks were also studied. The biomolecules easily adsorbed on the surface of the hydrophobic polysulfone networks whereas dangling hydrophilic chains on the surface prevented the adsorption of the biomolecules. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Polysulfone (PSU) is a widely used engineering thermoplastic polymer in membrane technology due to its excellent properties such as mechanical strength, thermal stability, chemical inert- ness and oxidative resistance [1]. To date, PSU membranes are prepared for the applications such as filtration, hemodialysis, bioartificial organs, gas separation, water purification systems, and fuel cells, etc. Although PSUs have extraordinary proper- ties, they suffer from some disadvantages limiting their usage in particular bioapplications. For example, hydrophobic nature results in poor blood compatibility and therefore, these materi- als are not suitable for filtration of protein containing solutions and blood-contacting applications [2,3]. The interaction between the proteins and PSU membrane leads to the adsorbtion of pro- ∗ Corresponding author at: Ege University, Faculty of Science, Biochemistry Department, Bornova, 35100 Izmir, Turkey. Tel.: +90 232 3438624; fax: +90 232 311 5485. ∗∗ Corresponding author at: Istanbul Technical University, Faculty of Science and Letters, Department of Chemistry, Maslak, 34469 Istanbul, Turkey. Tel.: +90 212 2853241; fax: +90 212 2856386. E-mail addresses: suna.timur@ege.edu.tr, sunatimur@yahoo.com (S. Timur), yusuf@itu.edu.tr (Y. Yagci). teins on the surface. The aggregation on the membrane disturbs the membrane properties such as permeation flux and selectiv- ity [4,5]. The adsorption of serum protein onto PSU membrane in blood can cause life-threatening problems in blood [6]. There- fore, tremendous effort has been devoted for the modification of PSUs that makes them suitable materials for such applications. The amphiphilic character is either achieved by sulfonation or flu- orination of PSU backbone or preparing block copolymers with suitable hydrophilic monomers or oligomers like polyglycol and polyvinyl pyrrolidone [7–9]. Hasegawa et al. [10] and Zhao et al. [11] modified the PSU membranes with hydrophilic phospholipid polymers and DNA, respectively and reduced the protein adsorp- tion. PSU and poly(ethylene glycol) (PEG) block copolymers were blended to improve hydrophilicity that results protein anti-fouling [11,12]. In order to reduce the protein adsorption and anti-fouling, hydrophilic PEG polymers are commonly used [13–18]. The increase in the PEG chain surface density increases the protein anti- fouling and decreases the protein adsorption [19,20]. The usage of the PEG polymers on the surface is extensively studied by many researchers [21,22]. It should be pointed out that due to the solu- bility of PEG in water, the mass loss of PEG is usually encountered particularly in protein studies and therefore, it is necessary to con- vert them into insoluble networks [23,24]. The crosslinked PEG has 0927-7765/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.colsurfb.2011.06.042