Viral-based nanoparticles

Viruses are a prime example of natural nanoparticles attenuated viral particles have been used in gene transfection and virus-based nanoparticles (VNP) studied as targeting systems (51,52). 

Lee CH, Kim JH, Lee HJ et al (2011) The generation of iPS cells using non-viral magnetic nanoparticle based transfection. Biomaterials 32 6683-6691... 

Early non-viral techniques involved the direct injection of naked DNA through the use of electrical impulses (electroporation), or bombardment with gold particles (gene gun), to force them across cellular membranes. However, these methods were inefficient, localized, and scarcely versatile. Non-viral carriers were developed using cationic lipids, polymers, carbon nanotubes, metal nanorods, and ceramic- and silica-based nanoparticles (Nishikawa Huang, 2001 Roy et al., 2003, 2005, 2008 Mintzer Simanek, 2009). 

Several cytotoxicity assays based on different mechanisms and measurement principles have been described in the literature. During safety assessment of new compounds, it is crucial to select a cytotoxicity assay addressing the correct mechanism. In this set of experiments, we use PEI (18-20) as model enhancer mimicking a possible effect of nanoparticles/delivery enhancers on cytotoxicity and epithelial barrier function. PEI polymers are widely used for non-viral gene delivery. For these kinds of enhancers, a cell membrane perforating mechanism is described in the literature. The rather high toxicity of PEI polymers is one of the major limiting factors especially for its in vivo use. 

Swami, A., Kurupati, R.K., Pathak, A., Singh, Y., Kumar, P., Gupta, K.C., 2007. A unique and highly efficient non-viral DNA/siRNA delivery system based on PEIbisepoxide nanoparticles. Biochem. Biophys. Res. Commun. 362 (4), 835—841. 

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