Carbohydrate Polymers 124 (2015) 35–42 Contents lists available at ScienceDirect Carbohydrate Polymers j ourna l ho me page: www.elsevier.com/locate/carbpol Antimicrobial and antioxidant surface modification of cellulose fibers using layer-by-layer deposition of chitosan and lignosulfonates Hui Li a,b,c,∗ , Lincai Peng b,d a Food Safety Research Institute, Kunming University of Science and Technology, Kunming 650500, China b State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China c Key Laboratory of Pulp and Paper Science & Technology of Ministry of Education of China, Qilu University of Technology, Jinan 250353, China d Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, China a r t i c l e i n f o Article history: Received 26 June 2014 Received in revised form 18 January 2015 Accepted 26 January 2015 Available online 12 February 2015 Keywords: Layer-by-layer Chitosan Lignosulfonates Antimicrobial activity Antioxidant activity Cellulose fibers a b s t r a c t To confer cellulose fibers antimicrobial and antioxidant activities, chitosan (CS)/lignosulfonates (LS) mul- tilayers were constructed on fibers surfaces through layer-by-layer deposition technique. The formation of CS/LS multilayers on cellulose fibers surfaces was verified by X-ray photoelectron spectroscopy (XPS) and zeta potential measurement. The surface morphologies of CS/LS multilayers on fibers surfaces were observed by atomic force microscopy (AFM). The results showed that characteristic element (i.e. N and S element) content increased with increasing bilayers number, the surface LS content increased linearly as a function of bilayers. Zeta potential of modified fibers was inversed after deposition of each layer. AFM phase images indicated that the cellulose microfibrils on fibers surfaces were gradually covered by granular LS aggregate. The antimicrobial testing results demonstrated that CS/LS multilayers modi- fied fibers with CS in the outermost layer exhibited higher antimicrobial activity against Escherichia coli. The antioxidant testing results showed that antioxidant activity of CS/LS multilayers modified fibers was better than that of original fibers under the same oxidation conditions. © 2015 Elsevier Ltd. All rights reserved. 1. Introduction Cellulose fibers are one of the most abundant, renewable, biodegradable and biocompatible natural polymers. Cellulose fibers and their derivatives have been used in a variety of appli- cations in several areas, such as textile industry, paper industry, packaging industry and medical field (Kalia, Thakur, Celli, Kiechel, & Schauer, 2013; Vuoti et al., 2013). However, the cellulose fibers- based materials are particularly easy to be attacked by fungi and bacterial during use and storage (Vartiainen et al., 2004). Micro- bial growth on the fibers-based materials leads to irreversible changes of a destructive character, which are the results of oxi- dation, hydrolysis and fission of cellulose chains (Silva et al., 2011). These chemical changes ultimately give rise to the mate- rials’ degradation, strength loss and even increasing the risk of infection in the medical field (Szostak-Kotowa, 2004; Dong et al., 2014). These detrimental effects can be avoided or controlled by ∗ Corresponding author at: Food Safety Research Institute, Kunming University of Science and Technology, Jingming South Road 727, Kunming 650500, China. Tel.: +86 087165920293. E-mail address: lihuiscut@126.com (H. Li). antimicrobial and antioxidant modification of cellulose fibers using specific agents (Martins et al., 2012). The selection of antimicrobial and antioxidant agent depended on the mechanism of antimicrobial and antioxidant activities, tox- icity and cost (Ammayappan & Moses, 2009). In recent years, natural and eco-friendly antimicrobial and antioxidant agents have attracted considerable attentions with increasing awareness of environment protection and concern for infectious diseases control (Kenny et al., 2014; Brewer, 2011). Chitosan (CS) is a natural cationic polysaccharide. Owing to its antimicrobial, nontoxic, hemostatic, biocompatible and biodegradable properties, chitosan has been widely used in various scientific fields, including biotechnology (Suginta, Khunkaewla, & Schulte, 2013), agriculture (Coqueiro, Maraschin, & Piero, 2011), food-preservation (Aider, 2010), medi- cal and pharmaceutical areas (Céline et al., 2013). Lignins are one of most useful natural resources and millions tons of technical lignins are produced globally each year, mainly as a by-product of the pulping industry (Calvo-Flores & Dobado, 2010). Lignins are nat- ural polyphenolic compounds that contain phenolic groups, which possess antioxidant characteristics (Dizhbite, Telysheva, Jurkjane, & Viesturs, 2004; García, Toledano, Andrés, & Labidi, 2010). Most studies have revealed the efficacy of different source technical lignins (such as kraft lignin, lignosulfonates, ethanol lignin) as http://dx.doi.org/10.1016/j.carbpol.2015.01.071 0144-8617/© 2015 Elsevier Ltd. All rights reserved.