title: Functionalization of carbon nanotubes enables non-covalent binding and intracellular delivery of small interfering RNA for efficient knock-down of genes.
abstract: The lipophilic nature of biological membranes restricts the direct intracellular delivery of potential drugs and molecular probes and makes intracellular transport one of the key problems in gene therapy. Because of their ability to cross cell membranes, single walled carbon nanotubes (SWNTs) are of interest as carriers of biologically active molecules, such as small interfering RNAs (siRNAs). We developed a strategy for chemical functionalization of SWNTs with hexamethylenediamine (HMDA) and poly(diallyldimethylammonium)chloride (PDDA) to obtain a material that was able to bind negatively charged siRNA by electrostatic interactions. PDDA-HMDA-SWNTs exhibited negligible cytotoxic effects on isolated rat heart cells at concentrations up to 10mg/l. PDDA-HMDA-SWNTs loaded with extracellular signal-regulated kinase (ERK) siRNA were able to cross the cell membrane and to suppress expression of the ERK target proteins in primary cardiomyocytes by about 75%. PDDA-functionalized SWNTs thus present an effective carrier system for applications in siRNA-mediated gene silencing.
authors.affiliation: Institute of Experimental and Clinical Pharmacology and Toxicology, University of Erlangen-Nuremberg, Fahrstr. 17, 91054 Erlangen, Germany.
authors.forename: Rasti
authors.initials: R
authors.lastname: Krajcik
authors.forename: Adrian
authors.initials: A
authors.lastname: Jung
authors.forename: Andreas
authors.initials: A
authors.lastname: Hirsch
authors.forename: Winfried
authors.initials: W
authors.lastname: Neuhuber
authors.forename: Oliver
authors.initials: O
authors.lastname: Zolk
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D004337:Drug Carriers / Q000737:chemistry*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics* / Q000378:metabolism; D020868:Gene Silencing; D032383:Myocytes, Cardiac / Q000502:physiology*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D034741:RNA, Small Interfering / Q000008:administration & dosage / Q000235:genetics*; D051381:Rats; D017208:Rats, Wistar; D014162:Transfection / Q000379:methods*
chemical_list: D004337:Drug Carriers; D037742:Nanotubes, Carbon; D034741:RNA, Small Interfering; D048049:Extracellular Signal-Regulated MAP Kinases