title: Hybrid polymer-grafted multiwalled carbon nanotubes for in vitro gene delivery.
abstract: Carbon nanotubes (CNTs) consist of carbon atoms arranged in sheets of graphene rolled up into cylindrical shapes. This class of nanomaterials has attracted attention because of their extraordinary properties, such as high electrical and thermal conductivity. In addition, development in CNT functionalization chemistry has led to an enhanced dispersibility in aqueous physiological media which indeed broadens the spectrum for their potential biological applications including gene delivery. The aim of this study is to determine the capability of different cationic polymer-grafted multiwalled carbon nanotubes (MWNTs) (polymer-g-MWNTs) to efficiently complex and transfer plasmid DNA (pCMV-βGal) in vitro without promoting cytotoxicity. Carboxylated MWNT is chemically conjugated to the cationic polymers polyethylenimine (PEI), polyallylamine (PAA), or a mixture of the two polymers. In order to explore the potential of these polymer-g-MWNTs as gene delivery systems, we first study their capacity to complex plasmid DNA (pDNA) using agarose gel electrophoresis. Gel migration studies confirm pDNA binding to polymer-g-MWNT with different affinities, highest for PEI-g-MWNT and PEI/PAA-g-CNT constructs. β-galactosidase expression is assessed in human lung epithelial (A549) cells, and the cytotoxicity is determined by modified LDH assay after 24 h incubation period. Additionally, PEI-g-MWNT and/or PEI/PAA-g-MWNT reveal an improvement in gene expression when compared to the naked pDNA or to the equivalent amounts of PEI polymer alone. Mechanistically, pDNA was delivered by the polymer-g-MWNT constructs via a different pathway compared to those used by polyplexes. In conclusion, polymer-g-MWNTs may be considered in the future as a versatile tool for efficient gene transfer in cancer cells in vitro, provided their toxicological profile is established.
authors.affiliation: Nanomedicine Laboratory, Centre for Drug Delivery Research, The School of Pharmacy, University of London, UK.
authors.forename: Antonio
authors.initials: A
authors.lastname: Nunes
authors.forename: Nadja
authors.initials: N
authors.lastname: Amsharov
authors.forename: Chang
authors.initials: C
authors.lastname: Guo
authors.forename: Jeroen
authors.initials: J
authors.lastname: Van den Bossche
authors.forename: Padmanabhan
authors.initials: P
authors.lastname: Santhosh
authors.forename: Theodoros K
authors.initials: TK
authors.lastname: Karachalios
authors.forename: Stephanos F
authors.initials: SF
authors.lastname: Nitodas
authors.forename: Marko
authors.initials: M
authors.lastname: Burghard
authors.forename: Kostas
authors.initials: K
authors.lastname: Kostarelos
authors.forename: Khuloud T
authors.initials: KT
authors.lastname: Al-Jamal
mesh_terms: D045744:Cell Line, Tumor; D004587:Electrophoresis, Agar Gel; D018014:Gene Transfer Techniques; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D050997:Nanomedicine / Q000379:methods; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D010957:Plasmids / Q000737:chemistry / Q000235:genetics; D011073:Polyamines / Q000737:chemistry; D011094:Polyethyleneimine / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D013059:Spectrum Analysis, Raman
chemical_list: D037742:Nanotubes, Carbon; D011073:Polyamines; D011108:Polymers; C063994:polyallylamine; D011094:Polyethyleneimine