International Journal of Pharmaceutics 389 (2010) 195–206 Contents lists available at ScienceDirect International Journal of Pharmaceutics journal homepage: www.elsevier.com/locate/ijpharm Pharmaceutical Nanotechnology Dextran–glycidyltrimethylammonium chloride conjugate/DNA nanoplex: A potential non-viral and haemocompatible gene delivery system Jane Joy Thomas, M.R. Rekha, Chandra P. Sharma ∗ Division of Biosurface Technology, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences & Technology, Trivandrum, Kerala, India article info Article history: Received 28 September 2009 Received in revised form 7 January 2010 Accepted 9 January 2010 Available online 18 January 2010 Keywords: Dextran GTAC CtDNA Nanoplex Haemocompatible Gene delivery abstract Non-viral gene carriers have attracted great interests for their unique properties. Cationic polymers have been in focus nowadays. Dextran is one of the most widely studied polymer in terms of gene therapy and in vivo disposition. But its applications are limited by its own drawbacks. To overcome the drawback, we have modified dextran using glycidyltrimethylammonium chloride (GTAC) bearing cationic groups. Nanoplexes were prepared using the derivative and calf thymus DNA (ctDNA) by reducing the surface charge and size of ctDNA. Complexation and stability of the nanoplex was proved using agarose gel elec- trophoresis and by Ethidium bromide (EtBr) displacement assay. Acid base titration studies were done to determine its buffering capacity. Derivatization was confirmed using NMR. Protection of ctDNA from nuclease digestion was evaluated. Stability of the nanoplex towards plasma components was analyzed. Its interactions with blood components were tested by haemolysis and aggregation studies. In vitro cyto- toxicity studies have been done to investigate the effect of nanoplex on HepG2 cells by MTT assay. This derivative has been proved to be feasible in transfection. The above investigations prove the capability of dextran modified with GTAC as a promising non-viral and haemocompatible gene delivery agent. © 2010 Elsevier B.V. All rights reserved. 1. Introduction For the past few decades, great interest has been stimulated in the treatment of human diseases by gene therapy. The success of gene therapy mainly depends on the development of transfect- ing agents that carry therapeutic genes into mammalian cells for gene expression (Suna and Kyung-Dall, 2008). Vectors or carriers play a major role in gene therapy due to the instability of naked plasmid DNA under in vivo conditions. The use of viral vectors as gene carriers remain associated with some dangerous adverse effects, inspite of their higher efficiencies for delivery and expres- sion. Serious problems that limit their use include pathogenicity, immunogenicity, wild type reversion, toxicity, release of virus in the semen of treated patients and expensiveness. Conversely, non- viral vectors offer unique advantages like lower immunogenicity, safety profiles, low cost production and lack of mutational potential (Hosseinkhani et al., 2004; Kim et al., 2005; Suna and Kyung-Dall, 2008; Cavallaro et al., 2008; Tsuchiya et al., 2006). Therefore there arises a need to optimize non-viral vectors to enhance the transfec- tion efficiency which generally do not reach adequate therapeutic levels. The key technology in improving the efficiency of non-viral vec- tors lies in the involvement of cationic polymers as the therapeutic ∗ Corresponding author. Tel.: +91 471 2520214; fax: +91 471 2341814. E-mail address: sharmacp@sctimst.ac.in (C.P. Sharma). gene carriers. Polycations are the promising candidates in the field of non-viral vectors because of their chemical diversity (Cavallaro et al., 2008). They are able to condense genetic material into com- pact nanosized structures by forming polyelectrolyte complexes. They mask the negative charges of DNA enabling the transfection of many types of cells (Vroman et al., 2007). Polycations used in gene delivery include polyethyleneimine (PEI), poly(l-lysine), poly(dimethyl aminoethyl methacry- late), pDMAEMA), poly(trimethyl aminoethyl methacrylate, p(TMAEMA), poly(vinylpyridine), chitosan, and diethylaminoethyl dextran (DEAE-dextran) (Hosseinkhani et al., 2004; Cavallaro et al., 2008). Several problems including low biocompatibility, toxicity, low biodegradability and low transfection efficiency still lie associated with polymeric gene delivery systems. Much attention has been devoted to the preparation of biopolymer nanoparticles and their application in the field of phar- maceutics. Several reports proved that nanoparticles made up of polysaccharides are provided with a sheathing property and increased blood half time (Hosseinkhani et al., 2004). The main approach is the use of cationic polymers that loose their DNA bind- ing properties within time. Many researchers were drawn to study and understand the importance of dextran and its derivatives due to its unique characteristics. Dextran is a biodegradable and bio- compatible polymer. Its straight chain consists of -1,6 glycosidic linkages with few -1,3 glycosidic linkages as the branch linkage (Yalpani and Hedman, 1985). Dextran fractions are stable for five years. They are readily soluble in water and electrolyte solutions. 0378-5173/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.ijpharm.2010.01.011