Biochemical Engineering Journal 78 (2013) 138–145 Contents lists available at ScienceDirect Biochemical Engineering Journal j o ur n al hom epa ge: www.elsevier.com/locate/bej Regular article Improvement of biofouling resistance on bacterial cellulose membranes Hengky Kurniawan a , Yun-Sheng Ye a , Wei-Hsuan Kuo a , Jinn-Tsyy Lai b , Meng-Jiy Wang a,∗ , Hwai-Shen Liu c,∗ a Department of Chemical Engineering, National Taiwan University of Science and Technology, 43, Keelung Road, Sec. 4, Taipei 106, Taiwan b The Food Industry Research and Development Institute (FIRDI), 331, Shih-Pin Road, Hsinchu 300, Taiwan c Department of Chemical Engineering, National Taiwan University, Sec. 4, No. 1, Roosevelt Road, Taipei 106, Taiwan a r t i c l e i n f o Article history: Received 30 October 2012 Received in revised form 23 March 2013 Accepted 25 March 2013 Available online 4 April 2013 Keywords: Acetobacter Antifouling Cellulose Bioinert Immobilization Tissue cell culture a b s t r a c t Bacterial cellulose possesses excellent biocompatibility and mechanical strength that show great poten- tials for biomaterial applications. In this study, the surface modifications of bacterial cellulose (BC) membranes were facilitated using either simple coating or chemical grafting methods. The surface coating method is to simply immobilize BC membranes with poly(ethylene glycol) (PEG) solutions of concentra- tion from 1 to 10%, followed by post-treatment with argon (Ar) plasma. The chemical method involved grafting mPEG (monofunctional methyl ether PEG) on BCs. The outcomes of surface modifications were characterized by surface chemical compositions (electron spectroscopy for chemical analysis (ESCA), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetry analysis (TGA), and surface morphology (atomic force microscopy (AFM) and scanning electron microscopy (SEM)). The effects of resistance to biofouling were verified by quantifying the adsorption of proteins and mammalian cells. The results showed that the PEG coating on BCs improved the resistance to cell adhesion by more than 30%. On the other hand, the specific chemical grafting resulted in a particularly high resistance to biofouling that the density of adherent cells reduced by more than 70% when compared to that on pristine BC. We have demonstrated that the two proposed methods were effective for the preparation of bioinert BC membranes with great potentials for applications in biomaterials and tissue engineering. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Microbial cellulose, a natural hydrogel-like polymer, is synthe- sized by the acetic bacterium Acetobacter xylinum in either static or agitated culture conditions. The high specific surface area, elastic- ity, wet strength and conformability characteristics of the bacterial cellulose fibrils are of great research interests for applications in food and beverage processing and in industries for the production of paper, plastic, membranes for separation, and fuel cells [1–6]. Microbial cellulose is also a good candidate for biomaterials due to its naturally high water content, high temperature resistance, good mechanical properties and biocompatibility. In particular, the non-toxicity and non-mutagenicity enable microbial cellulose to be a popular candidate for wound healing dressings and tissue engi- neering scaffolds [7–11]. For example, Klemm et al. reported using bacterial cellulose for temporary substitutes for skin and artifi- cial blood vessels [12]. The tubular BASYC ® bacterial cellulose was ∗ Corresponding authors. E-mail addresses: mjwang@mail.ntust.edu.tw (M.-J. Wang), hsliu@ntu.edu.tw (H.-S. Liu). fabricated as an artificial blood vessel and showed good mechanical strength in a wet state which exhibited high water absorption abil- ity and low inner surface roughness [12]. In addition, Zaborowska et al. have altered the porosity of BC membranes for the support of bone regeneration [13]. For biomedical implants, one of the most important consid- erations is the surface fouling phenomena that occur due to the nonspecific adsorption of proteins and undesired biomolecules [14–16]. The strategies that have been developed to reduce bio- fouling associated to graft the surface of materials with antifouling molecules or to incorporate self-assembling monolayers (SAMs) on the surface of materials [17,18]. The most commonly used antifouling molecules are polyacrylates [19,20], oligosaccharides and phospholipids [21–23], and poly(ethylene glycol) [24–26]. Among all the antifouling moieties, PEG is the most studied one due to its chain mobility, excluded volume effect, and osmotic repulsion which are responsible for the formation of a protective layer on the underlying surfaces [27–29]. Moreover, PEG is recognized as bio- compatible and weakly immunogenic due to its weakly basic ether linkage that resists the adsorption of proteins [30]. The reported methods for incorporating PEG onto materials were generally facil- itated by either physical or chemical methods. 1369-703X/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.bej.2013.03.021