Delivered by Ingenta to: Florida State University, College of Medicine IP: 5.8.47.242 On: Fri, 24 Jun 2016 07:31:30 Copyright: American Scientific Publishers Copyright © 2007 American Scientific Publishers All rights reserved Printed in the United States of America Journal of Nanoscience and Nanotechnology Vol. 7, 3700–3705, 2007 Anticancer Drug-Inorganic Nanohybrid and Its Cellular Interaction Ju Young Kim 1 , Soo-Jin Choi 1 , Jae-Min Oh 1 2 , Taeun Park 2 , and Jin-Ho Choy 1 ∗ 1 Center for Intelligent Nano-Bio Materials (CINBM), Division of Nanoscience and Department of Chemistry, Ewha Womans University, Seoul, 120-750, Korea 2 Nanohybrid Co. Ltd., Ewha Womans University, Seoul, 120-750, Korea An anticancer drug, methotrexate (MTX), has been successfully hybridized with layered double hydroxide (LDH) through co-precipitation route to produce MTX-LDH nanohybrids (MTX-LDH). According to the X-ray diffraction and FT-IR spectroscopy, it was confirmed that MTX molecules are stabilized in the interlayer space of LDHs by electrostatic interaction, maintaining their functional groups and structural integrity. According to the drug release study, the total amount of released MTX from the LDH lattice was determined to be larger under a simulated intracellular lysosomal condition (pH = 4.5) than simulated body fluid one (pH = 7.4). It is, therefore, expected that the MTX molecules in MTX-LDH can be effectively released in lysosomes, since the MTX release could be accelerated via ion-exchange reaction and dissolution of LDH in an acidic lysosomal condition. We also examined the anticancer efficacy of MTX-LDH in human breast adenocarcinoma MCF-7 cells. The cellular uptake of MTX was considerably higher in MTX-LDH-treated cells than in free MTX- treated cells, giving a lower IC 50 value for the former than the latter. All the results demonstrated that the MTX-LDH nanohybrid allows the efficient drug delivery in cells, and thus enhances drug efficacy. Keywords: Layered Double Hydroxide (LDH), Hybrid Material, Anticancer Drug, Efficient Drug Delivery, Methotrexate (MTX). 1. INTRODUCTION Nanohybrid systems have attracted considerable interest due to their potential applications in various fields, such as catalyst, electronics, semiconductors, cosmetics, and drug carriers. 1–6 In particular, bio-inorganic hybrid systems have deeply fascinated chemists as well as biologists, since they possess unique properties for biological applications by providing stabilization, targeted delivery, and controlled release of carried drugs and bio-active molecules. 7 8 Among various inorganic materials, layered double hydroxides (LDHs), also known as anionic clays, are promising candidates for drug delivery carriers. LDHs con- sist of positively charged layers and interlayer charge- compensating anions hydrated with water molecules. For a decade, intercalation chemistry of LDHs has been rapidly emerged with life sciences for biological applications. In particular, it has been demonstrated that LDHs can be a good candidate as the delivery carrier for DNA, 7 9 10 amino acid, 11 12 and drugs into cells, 8 13 since such an inor- ganic layered carrier can provide not only an enhanced ∗ Author to whom correspondence should be addressed. dissolution property, 8 15 thermal stability 16 17 and cellular interaction and uptake 14 but also a controlled release rate. 8 18 A well-known anticancer drug, methotrexate (MTX), which inhibits DNA, RNA, and protein synthesis by acting as a folate antagonist, 19 has been applied to certain human cancers, such as osteosarcoma and leukemia. However, due to very short plasma half-life and high efflux rate compared to influx rate, high administration dose was required. In order to overcome such demerits, we attempted to encapsulate MTX into LDH carrier lattice to form a hybridized MTX-LDH to get above mentioned advantages of LDH such as enhanced cellular transport and controlled drug release rate, particularly in cytosol and lysosomal conditions. We also examined drug efficacy of MTX-LDH by quantifying the cellular uptake of MTX in MTX-LDH nanohybrid as compared to MTX only. 2. EXPERIMENTAL DETAILS All chemical, Mg(NO 3  2 · 6H 2 O, Al(NO 3  3 · 9H 2 O, NaOH, and MTX were purchased from Aldrich Co., Ltd. Mg 068 Al 032 (OH) 2 (NO 3  032 · 0.1H 2 O was prepared by 3700 J. Nanosci. Nanotechnol. 2007, Vol. 7, No. 11 1533-4880/2007/7/3700/006 doi:10.1166/jnn.2007.061