Research Article Received: 2 September 2014 Revised: 21 October 2014 Accepted article published: 24 November 2014 Published online in Wiley Online Library: (wileyonlinelibrary.com) DOI 10.1002/pi.4844 Multifunctional membranes based on natural polymers: preparation, characterization and in vitro performance evaluation Sonia Trombino, a† Teresa Poerio, b,† Teresa Ferrarelli, a Maria Vittoria Mauro, c Cristina Giraldi, c Lidietta Giorno b and Roberta Cassano a* Abstract The aim of this study was to synthesize new multifunctional biopolymers via esterification of hemp fibres with two reagents: meso-2,3-dimercaptosuccinic acid and ethylenediaminetetraacetic acid. The obtained biopolymers were characterized using infrared spectroscopy. The antibacterial activity of the derivative containing ethylenediaminetetraacetic acid moiety was eval- uated by assessing the growth inhibition of Pseudomonas aeruginosa in Petri dishes. The results suggest that this biomaterial exhibits an excellent in vitro antibacterial activity. The antioxidant activity of the biopolymer from meso-2,3-dimercaptosuccinic acid was tested in rat liver microsomal membranes in the presence of tert-butylhydroperoxide as free radical source. Results suggest that this material inhibits lipid peroxidation induced by the free radical species. Both derivatives were used to pre- pare multifunctional membranes that were characterized and tested indicating the maintenance of biopolymer functionalized properties. Moreover, these functionalized biopolymers interact with metal ions due to their chelating functional groups. The absorption capacity for a selected metal ion, Cd(II), was investigated in aqueous solutions at pH = 0.65, 4.1 and 7.0 using optical emission spectroscopy. This study demonstrates that these new materials are very effective in chelating cadmium ions showing maximum efficiency at pH = 7.0. © 2014 Society of Chemical Industry Keywords: hemp fibres; antioxidant; antibacterial; chelation; membranes INTRODUCTION In recent years, interest in research and development of natural polymers has increased enormously. 1 – 5 This is due to these mate- rials being more easily biodegradable and disposable than plastics. Such materials can be used both as high-performance biopoly- mers (i.e. in medicine) and as off-power and low-cost biopolymers (i.e. disposable). Medical and pharmaceutical interest in natural polymers is growing rapidly because, after short- and long-term exposure, they do not appear to cause damage to the human body. 6 – 11 In addition, they contain easily modifiable functional groups that can be exploited to improve their properties and extend their applications. For example, a synthesis model has been designed and created for the production of a cotton fibre that exhibits antibiotic activity due to a bond with ampicillin. A product of this type may be used in hospital settings and also for the pro- duction of dressings for the treatment of chronic wounds. 9 – 11 With the purpose of extending the research in this field, a new biopoly- mer was synthesized, starting from cellulose extracted from hemp to obtain an innovative product with chelating, antibiotic and antioxidant properties. 8,12 – 17 Hemp was chosen as source of cel- lulose with the view of using the large amounts of vegetable waste produced during the extraction process and because of its remarkably low ecotoxicity compared to other crops. 18 Recently, these new biopolymers were used to prepare highly safe, selec- tive and eco-friendly membranes. 19 The coupling of modified nat- ural polymers with the properties and functionalities of specific membranes permits the obtaining of new materials to use in vari- ous fields. The materials that retain the properties of the function- alized biopolymers can have the following applications: in the ali- mentary field to preserve food quality and in the biomedical and pharmaceutical fields to improve the safety and stability of func- tional materials. 20 – 24 The aim of the work reported here was to derivatize hemp fibres with two reagents of known activity and to use these deriva- tives as fillers in a polysulfone (PSU) membrane matrix. Specifically, the reagents used to functionalize the OH group in position 6 of the glucosidic unit of cellulose were meso-2,3-dimercaptosuccinic acid (DMSA), an antioxidant and chelating agent, and ethylenedi- aminetetraacetic acid (EDTA), known for capturing heavy metals. ∗ Correspondence to: Roberta Cassano, Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87030, Rende, CS, Italy. roberta.cassano@unical.it † These authors contributed equally to this work. a Department of Pharmacy, Health and Nutritional Sciences, University of Cal- abria, 87030 Rende CS, Italy b Institute of Membrane Technology ITM-CNR, c/o University of Calabria, Rende CS, Italy c Virology and Microbiology Service of ‘Annunziata’ Hospital, 87100 Cosenza, Italy Polym Int (2014) www.soci.org © 2014 Society of Chemical Industry