IP: 146.185.205.133 On: Thu, 06 Dec 2018 06:16:51 Copyright: American Scientific Publishers Delivered by Ingenta Copyright © 2019 American Scientific Publishers All rights reserved Printed in the United States of America Article Journal of Nanoscience and Nanotechnology Vol. 19, 2489–2492, 2019 www.aspbs.com/jnn Derivatives of Graphene Oxide as Potential Drug Carriers Violetta Kozik 1 ∗ , Andrzej Bak 1 , Danuta Pentak 2 , Barbara Hachula 1 , Katarzyna Pytlakowska 1 , Marcin Rojkiewicz 1 , Josef Jampilek 3 ∗ , Karolina Sieron 4 , Joanna Jazowiecka-Rakus 5 , and Aleksander Sochanik 5 1 Institute of Chemistry, University of Silesia, Szkolna 9, 40-006 Katowice, Poland 2 Department of Physical Pharmacy, Faculty of Pharmacy, Medical University of Silesia, Jagiellonska 4, 41-200 Sosnowiec, Poland 3 Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Comenius University, 83232, Bratislava, Slovakia 4 Faculty of Health Sciences, Department of Physical Therapy – Department of Physical Medicine, Medical University of Silesia, ul. Medyków 12, 40-752, Katowice, Poland 5 Center for Translational Research and Molecular Biology of Cancer, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, 44-100 Gliwice, Poland Chemically functionalized graphene oxides could be used as novel drug carriers. Covalent alter- ations of graphene oxides lead to surface changes via formation of chemical bonding while non- covalent ones involve van der Waals forces, hydrogen bonding, and  – stacking interactions. Covalent modifications appear to be superior as they can yield compounds with desired properties and carriers prepared by other methods are less stable. Synthesis of graphene oxide-iminodiacetic acid and graphene oxide-glycine involves nucleophilic substitution of graphene oxide nanoparticles with iminodiacetic acid or glycine. As the first step, iminodiacetic acid or glycine were transformed into iminodiacetic acid or glycine methyl ester hydrochlorides, respectively, for C-terminus protec- tion. The obtained product, activated in situ, was then used to form amide bonds between graphene oxide and iminodiacetic acid or glycine. Keywords: Graphene Oxide, Nanoparticles, Drug Carriers, Iminodiacetic Acid, Glycine. 1. INTRODUCTION Chemistry of graphene (G) and graphene oxide (GO) 1 2 allows their broad modifications (both covalent and non-covalent) during synthesis, thus conferring them with novel properties. Introducing new functional groups allows, for example, to increase elasticity of the derived materials and obtain/or improve/their electrical and optical properties, 1 3 as well as change their mode of interaction with other molecules, 4 5 or affect their surface reactivity. 6 7 Modifications of G or GO permit creating hybrid materials with much more interesting properties than pure G. 8 Industrial-scale G production makes uses of graphite as a cheap substrate. Nonetheless,  – interactions between G layers result in their sticking and, consequently, agglom- eration of G in solution. Noncovalent functionalization of G is used to modify properties of this material as well ∗ Authors to whom correspondence should be addressed. as stabilize G layers in solution without disturbing elec- tronic properties of G layer. 9 10 Use of surfactants is a widely used method for functionalizing various nanocom- pounds. It permits modification of their hydrophobic and hydrophilic properties, which is of importance for such compounds bioavailability. 11 In addition use of ionic liq- uids makes it possible to obtain G solutions in organic solvents. 6 12 Due to the structure of GO that contains both zones formed by sp 2 -hybridized carbon atoms and also oxidized zones with sp 3 hybridization this compound has differ- ent reactivity compared to G (which contains exclusively sp 2 carbon atoms). Oxidized zones usually contain a large number of oxygen-containing moieties such as hydroxyl or epoxide groups. This confers to GO a hydrophilic char- acter. Theoretically, GO reduction should remove oxygen- containing groups and transform sp 3 atoms into sp 2 ones and give GO a fully aromatic character. Experimentally, it was found however that following reduction GO contains J. Nanosci. Nanotechnol. 2019, Vol. 19, No. 5 1533-4880/2019/19/2489/004 doi:10.1166/jnn.2019.15855 2489