1354
Cellulose (2018) 25:1353–1364
Keywords
Cellulose Antimicrobial
range of organisms, including bacteria, viruses and fungi (Russel and Hugo 1994; Damm et al. 2005). Simultaneously, concerns about the environmental impact of silver ions and particles have been growing in recent years, as expressed in literature (Bo¨swald et al. 1999; Venous 1999; Kim et al. 2009; Marambio- Jones and Hoek 2010; Echegoyen and Ner´ın 2013; Cushen et al. 2014). The content of silver in everyday goods, and thus also in packaging, is not currently regulated either in the European Union or in the United States of America (Seaton et al. 2010; Langauer- Lewowicka and Pawlas 2015; Mackevica et al. 2016). Since the influence of silver particles on the environ- ment and ecosystem is still a subject of intense scientific debate (Moore 2006; Bystrzejewska-Pio- trowska et al. 2009; Giri 2014), and as it has already been established that they also have a detrimental effect on the cells of animals including human and eukaryotic organisms (AshaRani et al. 2009; Panyala et al. 2008), it seems important to look for alternative materials that exhibit equally good antimicrobial properties but are safe to human beings. A solution to achieve this goal could be to trap silver ions or NPs in some kind of a solid matrix, which is one of the most important requirements of active packaging material because the contact of microbes and active agents should be selective and fully controlled, as described by Restuccia et al. (2010). Impregnation of silver cations onto the surface of the solid support could be a way to prevent silver migration. Another idea would be to use a solid of high surface area to enable contact with microbes. For this purpose, zeolite minerals seem a prospective media for silver anchoring, then used as an additive to other material such as paper (Baldevraj and Jagadish 2011). The use of zeolite as a filler in polymeric materials has been reported in literature (Bastani et al. 2013). Some authors suggest that zeolites can enhance the antibacterial activity of thus prepared composite materials (Matsumura et al. 2003; Odabas¸ et al. 2011). The addition of zeolites to paper has a positive influence on its properties, such as change in acidity, permeability and resistance to hazardous compounds such as sulphur dioxide, nitrogen oxides and VOCs (Bishop et al. 2008; O’Connell et al. 2008). The goal of this research is to develop innovative, environmentally friendly packaging material based on paper with high biocidal activity, mechanical resis- tance and stable chemical compositions, and with the
Physicochemical properties Silver
Introduction
Zeolites and zeolite-based materials are biocompatible minerals that are commonly used in a variety of antibacterial and antifungal applications, such as medicine (Matsuura et al. 1997; Danilczuk et al. 2008), food packaging (Zagory 1995; Suslow and Crops 1997; Appendini and Hotchkiss 2002) and the clothing industry (Takai et al. 2002; Grancaric et al. 2012). According to the literature, there is still a need for intensive research into new materials that could offer additional features in comparison to those currently available (Zampino et al. 2011; Fang et al. 2014; Vukoje et al. 2014), and which may be used as active packaging for the safe storage of a great many types of goods. The antimicrobial properties of modified natural polymers are of great interest (Kukharenko et al. 2014; Littunen et al. 2016), but the mobility and potential migration of silver in such materials can be problematic. The antimicrobial properties of different porous materials are also still being tested (Wang et al. 2006; Yang et al. 2009; Azo´car et al. 2012; Nassar and Youssef 2012; Youssef et al. 2013), and zeolites seem to be the best alternative because of their mechanical resistivity, sorptive and catalytic properties which can eliminate or decrease the problem of environmental risks. Packaging is defined as ‘‘active’’ if it can provide mechanical, chemical and antimicrobial protection for the items stored inside (Gutie´rrez et al. 2009). Thus, active packaging should not only protect the stored objects, but also extend their shelf-life. Such func- tionalities can be secured by using packaging capable of the absorption of odours arising from the degrada- tion of organic items, especially of compounds containing sulphur or other volatile organic com- pounds (Vermeiren et al. 1999). Another valuable property of packaging materials is their antimicrobial activity against bacteria, fungi and viruses (Vermeiren et al. 1999). Silver has, since ancient times, been known as a biocide, a property that is today exploited by the addition of silver nanopar- ticles (NPs) to many everyday goods. The antimicro- bial activity of silver has been confirmed on a wide
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