Multilayered polyelectrolyte films promote the direct and localized delivery of DNA to cells.
ABSTRACT 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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ABSTRACT: Herein, we describe the delivery of plasmid DNA (pDNA) using silk fibroin (SF) layer-by-layer assembled microcapsules. Deposition of fluorescently labeled SF onto polystyrene (PS) template particles resulted in increasing fluorescence intensity and decreasing surface charge in correlation to SF layer number. After removal of the PS core, hollow, monodisperse, and structurally stable SF microcapsules of variable size and shell thickness were obtained. Plasmid DNA encoding for enhanced green fluorescent protein (eGFP) was loaded onto 1 or 4 μm capsules, either by incorporation of pDNA within the innermost layer of the shell or by adsorption to the microcapsules surface, and in vitro pDNA release, cytotoxicty and eGFP expression were studied. Sustained pDNA release over 3 days was observed using both loading techniques, being accelerated in the presence of protease. DNA loaded SF microcapsules resulted in efficient cell transfection along with low cytotoxicity after 3 days incubation compared to treatment with pDNA/branched polyethylenimine complexes. Among the tested conditions highest transfection efficiencies were achieved using 1 μm capsules where pDNA was adsorbed to the capsule surface. Our results suggest that SF microcapsules are suitable for the localized delivery of pDNA, combining low cytotoxicity and high transfection efficiency.Biomaterials 06/2014; · 8.31 Impact Factor
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ABSTRACT: Layer-by-layer (LbL) assembly is a powerful tool with increasing real world applications in energy, biomaterials, active surfaces, and membranes; however, the current state of the art requires individual sample construction using large quantities of material. Here we describe a technique using capillary flow within a microfluidic device to drive high-throughput assembly of LbL film libraries. This capillary flow layer-by-layer (CF-LbL) method significantly reduces material waste, improves quality control, and expands the potential applications of LbL into new research spaces. The method can be operated as a simple lab bench top apparatus or combined with liquid handling robotics to extend library size. Here we describe and demonstrate the technique and establish its ability to recreate and expand on known literature for film growth and morphology. We use the same platform to assay biological properties such as cell adhesion and proliferation, and ultimately provide an example of the use of this approach to identify LbL films for surface-based DNA transfection of commonly used cell types.ACS Nano 05/2014; · 12.03 Impact Factor
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ABSTRACT: The use of surface-based methods for the delivery of therapeutics has recently generated increasing interest. These platforms have tremendous potential to minimize detrimental side effects associated with systemic delivery by localizing the therapeutic vehicle, and thus provide higher local doses for improved efficacy. Cationic lipids are one of the most commonly used synthetic carriers for the delivery of genetic cargo, such as DNA and RNA. However, reports on the use of lipid-based films for gene delivery are scarce. Here we investigate the use of a lipid-based film for the in vitro delivery of plasmid DNA. Solid DNA-lipid films show very low levels of transfection, while identical complexes prepared for bolus delivery provide high levels of transfection when used directly. We investigate the mechanism, whereby the activity of these solid-state films is lost and suggest methods for circumventing these challenges and restoring the efficacy of these films as gene delivery platforms. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3203–3213, 2013AIChE Journal 09/2013; 59(9). · 2.58 Impact Factor