b-Cyclodextrin-grafted TEMPO-oxidized cellulose nanofibers for sustained release of essential oil Seema Saini 1,2 , Deborah Quinot 2 , Nathalie Lavoine 3 , Mohamed Naceur Belgacem 1,2 , and Julien Bras 1,2, * 1 Univ. Grenoble Alpes, LGP2, 38000 Grenoble, France 2 CNRS, LGP2, 38000 Grenoble, France 3 Department of Biomaterials Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan Received: 9 September 2016 Accepted: 25 November 2016 Ó Springer Science+Business Media New York 2016 ABSTRACT The present investigation deals with the development and characterization of a new controlled release packaging system for food. Novel sustained system was developed by direct grafting of beta-cyclodextrin (bCD) on the carboxyl groups of TEMPO-oxidized cellulose nanofibers (TEMPO-CNF) in aqueous solution and without using any spacer. Carvacrol, an aromatic essential oil component, was then entrapped in the ensued CD-grafted TEMPO-CNF. Successful func- tionalization of TEMPO-CNF was confirmed by conductometric titration, Fourier Transform Infrared Spectroscopy, and gravimetric analyses. The bCD- grafted TEMPO-CNF films exhibited sustained release of carvacrol over 150 h before reaching the equilibrium in water. Antimicrobial activity of carvacrol against Bacillus subtilis was increased (or improved by 47 h) from 3 h when using TEMPO-CNF to around (or against) 50 h when using CD-grafted TEMPO- CNF. These promising results pave the way for the development of new bio- based controlled release packaging materials with efficient antibacterial activity. Introduction In contemporary society with increasing communi- cation systems, worldwide logistics, industrializa- tion, and changing consumer expectations generated concerns about food safety and preservation remain/ persist as key challenges for the coming years [1]. In spite of the abundant food cultivated worldwide, people die either due to lack of food or food borne illnesses caused by the unsafe food containing bac- teria, parasite, or viruses. In order to satisfy the changing consumer needs, the concept of active packaging was introduced which is a more advanced and creative system than traditional counterpart. Conventionally, the antimicrobial compounds are either mixed or coated over food formulation for preservation and increased shelf life. However, this traditional method has some limitations such as the degradation of the organoleptic properties of food or the inactivation of the antimicrobial effect/activity after a very short period of time, which finally results into loading excessive amount of preservatives/ Address correspondence to E-mail: julien.bras@grenoble-inp.fr DOI 10.1007/s10853-016-0644-7 J Mater Sci