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Linear DNA Low Efficiency Transfection by Liposome Can Be Improved by the Use of Cationic Lipid as Charge Neutralizer

Authors

  • Andrea von Groll,

    1. Departamento de Patologia Clínica Veterinária, Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul, Campus do Vale, Porto Alegre, RS, Brazil
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  • Yan Levin,

    1. Departamento de Física Teórica, Instituto de Física, Universidade Federal do Rio Grande do Sul, Campus do Vale, Porto Alegre, RS, Brazil
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  • Marcia C. Barbosa,

    1. Departamento de Física Teórica, Instituto de Física, Universidade Federal do Rio Grande do Sul, Campus do Vale, Porto Alegre, RS, Brazil
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  • Ana P. Ravazzolo

    Corresponding author
    1. Departamento de Patologia Clínica Veterinária, Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul, Campus do Vale, Porto Alegre, RS, Brazil
    • Departamento de Patologia Clínica Veterinária, Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul, Campus do Vale, Porto Alegre, RS, Brazil. Phone: (55) 5133166141. Fax: (55) 5133167305
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Abstract

A plasmid expressing the β-galactosidase enzyme was used to transfect Vero cells in order to evaluate the efficiency of a liposome-mediated transfection by circular and linear DNA. The results obtained showed a low rate of transfection by linear DNA:liposome complexes. To explore whether the structure of the complexes was interfering with the transfection, atomic force microscopy (AFM) was used. It has confirmed the difference between the linear and circular condensates: whereas the circular DNA:liposome complexes presented compact spherical or cylindrical structures of about 100–800 nm, the linear DNA showed pearl necklace-like structures, with pearls varying from 250 to 400 nm. On the basis of the theory proposed by Kuhn et al. (1999), low concentrations of cationic amphihile were used to neutralize or reverse the DNA charge in order to improve the transfection efficiency of the linearDNA. Using this method, we were able to obtain the expression of the transgene without an associated toxicity observed with the linear DNA liposome delivery.

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