Multilayered polyelectrolyte films promote the direct and localized delivery of DNA to cells

Department of Chemical and Biological Engineering, University of Wisconsin - Madison, 1415 Engineering Drive, Madison, Wisconsin 53706-1607, USA.
Journal of Controlled Release (Impact Factor: 7.71). 09/2005; 106(1-2):214-23. DOI: 10.1016/j.jconrel.2005.04.014
Source: PubMed


Multilayered polyelectrolyte films fabricated from plasmid DNA and a hydrolytically degradable synthetic polycation can be used to direct the localized transfection of cells without the aid of a secondary transfection agent. Multilayered assemblies 100 nm thick consisting of alternating layers of synthetic polymer and plasmid DNA encoding for enhanced green fluorescent protein (EGFP) were deposited on quartz substrates using a layer-by-layer fabrication procedure. The placement of film-coated slides in contact with COS-7 cells growing in serum-containing culture medium resulted in gene expression in cells localized under the film-coated portion of the slides. The average percentage of cells expressing EGFP relative to the total number of cells ranged from 4.6% to 37.9%, with an average of 18.6%+/-8.2%, as determined by fluorescence microscopy. In addition to providing a mechanism for the immobilization of DNA at the cell/surface interface, a preliminary analysis of film topography by atomic force microscopy (AFM) demonstrated that polymer /DNA films undergo significant structural rearrangements upon incubation to present surface bound condensed plasmid DNA nanoparticles. These data suggest that the presence of the cationic polymer in these materials may also contribute to the internalization and expression of plasmid. The materials and design principles reported here present an attractive framework for the local or non-invasive delivery of DNA from the surfaces of implantable materials or biomedical devices.

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    • "Une fois implanté à l'endroit souhaité de l'organisme hôte, le gel doit résister aux diverses contraintes mécaniques et conserver son volume pendant une durée suffisante tout en transmettant ces contraintes aux cellules encapsulées . Dans le cas classique des gels d'alginate, la valeur du module de compression peut être accrue en augmentant la concentration volumique en alginate ainsi que le rapport du nombre de groupements α-L-guluronique (G dans la figure 3b) au nombre de groupements β-D-mannuronique (M dans la A B Figure 8 -A) Schéma de principe de préparation de l'architecture multicouche consistant à déposer de manière séquentielle le polycation hydrolysable et le plasmide (ici le pEGFP) et de l'hydrolyse progressive du film lorsque celui-ci est placé à pH 7,2 et à 37 °C ; B) Schéma montrant la possibilité de réaliser une « expression génique localisée » lors de la mise en contact d'une lamelle de quartz fonctionnalisée avec l'architecture illustrée en A avec une couche de cellules (d'après [31]). "

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    • "Solutions of SPS used for film fabrication were prepared by mixing unlabeled commercially available SPS with SPS FL in a ratio of 9:1 (w/w). Films having the structure (LPEI/SPS FL ) 10 (1/DNA) 8 were fabricated layer-by-layer on silicon substrates using methods described in past studies (Fredin et al., 2005; 2007; Jewell et al., 2005; Zhang et al., 2004), such that SPS FL was incorporated into every layer of the LPEI/SPS bilayers used to form the film. Figure 1C shows a LSCM image of a film having this structure imaged prior to incubation. "
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