Contents lists available at ScienceDirect Colloids and Surfaces B: Biointerfaces journal homepage: www.elsevier.com/locate/colsurfb Functionalized graphene oxides for drug loading, release and delivery of poorly water soluble anticancer drug: A comparative study Neha Karki a , Himani Tiwari a , Mintu Pal b , Alok Chaurasia c , Rajaram Bal d , Penny Joshi a , Nanda Gopal Sahoo a, ⁎ a Nanoscience and Nanotechnology Centre, Department of Chemistry, D.S.B. Campus, Kumaun University, Nainital, Uttarakhand, India b Biotechnology Group, Biological Sciences and Technology Division, CSIR-North East Institute of Science and Technology, Academy of Scientific and Innovative Research, Jorhat, Assam, India c Tindal Consultancy Services Pvt Ltd, West Bengal, India d Conversion & Catalysis Division, CSIR-Indian Institute of Petroleum, Dehradun, India ARTICLE INFO Keywords: Biocompatible Cytotoxicity Graphene Nanocarrier SN-38 ABSTRACT In this work, the modification of graphene oxides (GOs) have been done with hydrophilic and biodegradable polymer, polyvinylpyrrolidone (PVP) and other excipient β -cyclodextrin (β-CD) through covalent functiona- lization for efficient loading and compatible release of sparingly water soluble aromatic anticancer drug SN-38 (7-ethyl-10-hydroxy camptothecin). The drug was loaded onto both GO-PVP and GO-β-CD through the π-π interactions.The release of drug from both the nanocarriers were analyzed in different pH medium of pH 7 (water, neutral medium), pH 5 (acidic buffer) and pH 12 (basic buffer). The loading capacity and the cell killing activity of SN-38 loaded on functionalized GO were investigated comprehensively in human breast cancer cells MCF-7.Our findings shown that the cytotoxicity of SN-38 loaded to the polymer modified GO was comparatively higher than free SN-38. In particular, SN-38 loaded GO-PVP nanocarrier has more cytotoxic effect than GO-β-CD nanocarrier against MCF-7 cells, indicating that SN-38 loaded GO-PVP nanocarrier can be used as promising material for drug delivery and biological applications. 1. Introduction The exponentially emergent call for advances in the efficient diag- nosis and treatment of various malignant diseases has stimulated a wide range of interdisciplinary science community to innovate an efficient and undisruptive drug delivery system. Graphene, with a sp 2 -hy- brirdized 2D framework has produced pioneering results and attracted a great research interest across the globe owing to its remarkable me- chanical strength, electrical as well as thermal conductivity and large specific surface area [1–4]. Because of these extraordinary properties, graphene provides essentially infinite prospective for various applica- tions such as green energy, biomedical, electronics, and nanocompo- sites etc. Graphene oxides (GOs) develop during oxidation of graphene, which have oxygenated hydrophilic functionalities at the surface of GO such as hydroxyl (-OH), epoxy (> O), and at the edges such as car- boxylic (-COOH) groups. These functional groups promote the inter- calation of water molecules into the covered passage and they can be easily detached by ultra-sonication that helps to produce highly dis- persible GO sheets in aqueous medium [5–8]. The exfoliated GO can be further functionalized for drug delivery applications. Owing to these potent hydrophilic groups present on the surface of GO, the assistance of being high dispersion in water and physiological environments is attained by GO. Due to these oxygen containing groups, GO can be further functionalized covalently or noncovalently for its required ap- plications accordingly [9]. Importantly, GO has specific and large sur- face area which is exclusively accessible from top and bottom sides of GO sheets and offer effective immobilization/loading of various che- micals as well as biomolecules (drugs, genes, proteins, etc.). Graphene has enormous potential to penetrate through the plasma membrane resulting into the enhanced cellular uptake of desired micro [10,11] and macromolecules [12,13] with excellent biocompatibility made GO a magical vehicle for drug delivery applications. The targeted drug delivery concept predominantly shows potential application in the biomedical field, where the developments of different therapeutic sys- tems are significant to get better efficacy, reduces dose amount and eliminate adverse effects. As we know, the majority of anticancer drugs are either insoluble or sparingly soluble in water as well as in biological medium due to their https://doi.org/10.1016/j.colsurfb.2018.05.022 Received 13 February 2018; Received in revised form 5 May 2018; Accepted 7 May 2018 ⁎ Corresponding author. E-mail address: ngsahoo@yahoo.co.in (N.G. Sahoo). Colloids and Surfaces B: Biointerfaces 169 (2018) 265–272 0927-7765/ © 2018 Elsevier B.V. All rights reserved. T