Evaluation of Poly(amidoamine) Dendrimer Surface Modification with Poly(ethylene glycol) on Cytotoxicity Reduction

Authors
F. Jafari Iri Sofla 1
F. Rahbarizadeh 1
D. Ahmadvand 2
1 Department of Medical Biotechnology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
2 School of Allied Medical Sciences, Iran University of Medical Sciences, Tehran, Iran
Abstract
Objective: Generation 5 poly (amidoamine) dendrimers are promising multipotent gene delivery vectors that provide favorable DNA condensation properties; however, their high toxicity limits their applications. Toxicity of PAMAM dendrimers depends on their type, generation and applied dosage in a way that lower generations (lower than G5 dendrimers) and anionic dendrimers have lower toxicity than higher generations and cationic dendrimers. The aim of this study is to evaluate the effect of PEGylation on toxicity of G5 PAMAM dendrimers.
Methods: In this study, to improve their characteristics as gene delivery carriers, G5 PAMAM dendrimers were conjugated to polyethylene glycol molecules (PEG, molecular weight 3500) at three different molar ratios of 10, 20 and 30. Also the number of conjugated PEG chains was quantified using TNBSA and Ellman assays. The effect of different degrees of PEGylation on cytotoxicity and transfection efficiency of modified PAMAM dendrimers toward BT-474 and MCF-10A cell lines were assessed.
Results: Compared to unconjugated, PEG conjugated PAMAM dendrimers had lower in vitro cytotoxicity, particularly at higher PEG to PAMAM molar ratios. Among all prepared PEG-PAMAM dendrimers, G5 PAMAM dendrimers that conjugated to PEG at a molar ratio of 10/1 had the highest in vitro transfection rate in both cell lines.
Conclusion: Our results showed that these PEG-conjugated PAMAM dendrimers possess a great potential for in vitro gene delivery.

Keywords

[1]     Svenson S, Tomalia DA. Dendrimers in biomedical applications--reflections on the field. Adv Drug Deliv Rev 2005; 57(15): 2106-29.
[2]     Esfand R, Tomalia DA. Poly(amidoamine) (PAMAM) dendrimers: from biomimicry to drug delivery and biomedical applications. Drug Discov Today 2001; 6(8): 427-436.
[3]     Hawker CJ, Frechet JMJ. Preparation of polymers with controlled molecular architecture. A new convergent approach to dendritic macromolecules. J Am Chem Soc1990; 112(21): 7638-47.
[4]     Eichman JD, Bielinska AU, Kukowska-Latallo JF, Baker JR Jr. The use of PAMAM dendrimers in the efficient transfer of genetic material into cells. Pharm Sci Technolo Today 2000; 3(7): 232-245.
[5]     Jevprasesphant R, Penny J, Attwood D, McKeown NB, D'Emanuele A. Engineering of dendrimer surfaces to enhance transepithelial transport and reduce cytotoxicity. Pharm Res 2003; 20(10): 1543-50.
[6]     Kim Y, Klutz AM, Jacobson KA. Systematic investigation of polyamidoamine dendrimers surface-modified with poly(ethylene glycol) for drug delivery applications: synthesis, characterization, and evaluation of cytotoxicity. Bioconjug Chem 2008; 19(8): 1660-72.
[7]     Fant K, Esbjörner EK, Jenkins A, Grossel MC, Lincoln P, Nordén B. Effects of PEGylation and acetylation of PAMAM dendrimers on DNA binding, cytotoxicity and in vitro transfection efficiency. Mol Pharm 2010; 7(5): 1734-46.
[8]     Hong S, Bielinska AU, Mecke A, Keszler B, Beals JL, Shi X, Balogh L, Orr BG, Baker JR Jr, Banaszak Holl MM. Interaction of poly(amidoamine) dendrimers with supported lipid bilayers and cells: hole formation and the relation to transport. Bioconjug Chem 2004; 15(4): 774-82.
[9]     Jevprasesphant R, Penny J, Jalal R, Attwood D, McKeown NB, D'Emanuele A. TThe influence of surface modification on the cytotoxicity of PAMAM dendrimers. Int J Pharm 2003; 252(1-2): 263-6.
[10] Kolhatkar RB, Kitchens KM, Swaan PW, Ghandehari H. Surface acetylation of polyamidoamine (PAMAM) dendrimers decreases cytotoxicity while maintaining membrane permeability. Bioconjug Chem 2007; 18(6): 2054-60.
[11] Luo D, Haverstick K, Belcheva N, Han E, Saltzman WM. Poly (ethylene glycol) -conjugated PAMAM dendrimer for biocompatible, high-efficiency DNA delivery. Macromolecules 2002; 3456–62.
[12] Qi R, Gao Y, Tang Y, He RR, Liu TL, He Y, Sun S, Li BY, Li YB, Liu G. PEG-conjugated PAMAM dendrimers mediate efficient intramuscular gene expression. AAPS J 2009; 11(3): 395-405.
[13] Ogris M, Steinlein P, Carotta S, Brunner S, Wagner E. DNA/polyethylenimine transfection particles: influence of ligands, polymer size, and PEGylation on internalization and gene expression. AAPS PharmSci 2001; 3(3): E21.

 
 
 
Pathobiology Reserach
Volume 18, Issue 1
April 2015
Pages 23-38