Colloids and Surfaces B: Biointerfaces 149 (2017) 23–29 Contents lists available at ScienceDirect Colloids and Surfaces B: Biointerfaces journal homepage: www.elsevier.com/locate/colsurfb PEG-mimetic peptoid reduces protein fouling of polysulfone hollow fibers Neda Mahmoudi a , Lauren Reed a , Alex Moix a , Nawaf Alshammari b , Jamie Hestekin a , Shannon L. Servoss a,∗ a Ralph E. Martin Department of Chemical Engineering, University of Arkansas, United States b Cell and Molecular Biology, University of Arkansas, United States a r t i c l e i n f o Article history: Received 22 May 2016 Received in revised form 20 September 2016 Accepted 26 September 2016 Available online 26 September 2016 Keywords: Biofouling Peptoid Polysulfone Hollow fiber membrane Biocompatibility a b s t r a c t Biofouling is a persistent problem for membranes exposed to blood or other complex biological flu- ids, affecting surface structure and hindering performance. In this study, a peptoid with 2-methoxyethyl (NMEG5) side chains was immobilized on polysulfone hollow fiber membranes to prevent protein fouling. The successful attachment of NMEG5 to the polysulfone surface was confirmed by X-ray photoelectron spectroscopy and an increase in hydrophilicity was confirmed by contact angle analysis. The NMEG5- modified surface was found to resist fouling with bovine serum albumin, lysozyme, and adsorbed significantly less fibrinogen as compared with other published low-fouling surfaces. Due to the low fouling nature and increased biocompatibility of the NMEG5 coated membranes, they have potential applicability in numerous biomedical applications including artificial lungs and hemodialysis. © 2016 Elsevier B.V. All rights reserved. 1. Introduction Membranes are widely used in medical devices including oxy- genators, cardiovascular implants, hemodialysis, and diagnostic devices [1,2]. Polysulfone (PSU) is one of the most common polymers for biomedical membrane applications due to its high chemical, physical, and thermal stability, as well as high porosity [3–5]. However, proteins and other materials adsorb to the PSU membrane surface and within its pores, referred to as membrane fouling or biofouling [1–4]. This results in coagulation at the surface that leads to a decrease in flux across the membrane, substantial energy consumption, and a significant increase in operational cost [1,6]. The biocompatibility of PSU membranes must be improved to be more viable for use in biomedical devices [1,5]. Membrane fouling occurs due to hydrogen bonding, hydropho- bic, electrostatic, and van der Waals interactions between the biological foulants and the membrane surface [1,7]. Surface prop- erties that affect fouling include wettability, surface free energy, surface charge, and roughness [8–11]. Research suggests that effec- ∗ Corresponding author at: Ralph E. Martin Department of Chemical Engineering, University of Arkansas, 3202 Bell Engineering Center, Fayetteville, AR 72701, United States. E-mail address: sservoss@uark.edu (S.L. Servoss). tive non-fouling surfaces should be (i) hydrophilic, (ii) electrically neutral, (iii) free of hydrogen bond donors, and (iv) contain hydro- gen bond acceptors [12,13]. Hydrophilicity, or wettability, of the surface affects protein adsorption, electrically neutral surfaces min- imize electrostatic interactions, and elimination of hydrogen bond donors minimizes hydrogen bonding [14]. Therefore, a hydrophilic and electrically neutral surface with the absence of hydrogen bond donor groups is preferred for ultra-low fouling applications. One approach to improve the biocompatibility and reduce fouling of PSU membranes is to alter the surface properties to decrease hydrophobicity [3,15]. This has previously been achieved by surface immobilization of self-assembled monolayers and antifouling polymers [16,17] including poly-ethylene-glycol (PEG), oligo-ethylene-glycol (OEG), and their derivatives [18,19]. Messer- smith and co-workers used 3,4-dihydroxyphenylalanine (DOPA) to attach PEG to TiO 2 substrate. These PEG modified surfaces were found to decrease cell adhesion by 98% compared to con- trol surfaces for up to two weeks [19]. However, PEG and OEG are susceptible to oxidative degradation in vivo that limits long-term use in physiological environments [20–24]. Alternatives to PEG include carbohydrate derivatives [25], poly(2-methyl-2-oxazoline) [26], zwitterionic polymers [27], glycomimetics [28], and poly-N- subsituted glycines (peptoids) [13,22,29,30]. Each of these coatings exhibit antifouling properties and have different advantages that can be leveraged for various applications. Here we have chosen to http://dx.doi.org/10.1016/j.colsurfb.2016.09.038 0927-7765/© 2016 Elsevier B.V. All rights reserved.