Investigation of Dendriplexes by Ion Mobility-Mass Spectrometry

Molecules

Emma-Dune Leriche²  Marie Hubert-Roux²  Carlos Afonso²  Catherine M. Lange²  Martin C. Grossel¹  Florian Maire²  Corinne Loutelier-Bourhis² 

[1] School of Chemistry, University of Southampton, Highfield, Hants SO17 1BJ Southampton, UK;Normandie Université, COBRA, UMR6014 and FR3038, Université de Rouen; INSA de Rouen; CNRS, IRCOF, 1 rue Tesnière, 76821 Mont-Saint-Aignan Cedex, France

关键词: polyamidoamine dendrimers;    oligonucleotide duplex;    dendriplexes;    electrospray mass spectrometry;    tandem mass spectrometry;    ion mobility spectrometry;   

DOI  :  10.3390/molecules191220731

来源: mdpi

【 摘 要 】

Highly branched polyamidoamine (PAMAM) dendrimers presenting biological activities have been envisaged as non-viral gene delivery vectors. They are known to associate with nucleic acid (DNA) in non-covalent complexes via electrostatic interactions. Although their transfection efficiency has been proved, PAMAMs present a significant cytotoxicity due to their cationic surface. To overcome such a drawback, different chemical modifications of the PAMAM surface have been reported such as the attachment of hydrophobic residues. In the present work, we studied the complexation of DNA duplexes with different low-generation PAMAM; ammonia-cored G0(N) and G1(N) PAMAM, native or chemically modified with aromatic residues, i.e., phenyl-modified-PAMAM G0(N) and phenylalanine-modified-PAMAM G1(N). To investigate the interactions involved in the PAMAM/DNA complexes, also called dendriplexes, we used electrospray ionization (ESI) coupled to ion mobility spectrometry-mass-spectrometry (IM-MS). ESI is known to allow the study of non-covalent complexes in native conditions while IM-MS is a bidimensional separation technique particularly useful for the characterization of complex mixtures. IM-MS allows the separation of the expected complexes, possible additional non-specific complexes and the free ligands. Tandem mass spectrometry (MS/MS) was also used for the structural characterization. This work highlights the contribution of IM-MS and MS/MS for the study of small dendriplexes. The stoichiometries of the complexes and the equilibrium dissociation constants were determined. The [DNA/native PAMAM] and [DNA/modified-PAMAM] dendriplexes were compared.

【 授权许可】

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© 2014 by the authors; licensee MDPI, Basel, Switzerland.