Assembly of erodible, DNA-containing thin films on the surfaces of polymer microparticles: Toward a layer-by-layer approach to the delivery of DNA to antigen-presenting cells

Abstract

We report a layer-by-layer approach to the assembly of ultrathin and erodible DNA-containing films on the surfaces of polymer microparticles. DNA-containing multilayered films were fabricated layerby-layer on the surfaces of polystyrene microspheres (~6 μm) by iterative and alternating cycles of particle suspension, centrifugation, and resuspension in solutions of plasmid DNA and a hydrolytically degradable polyamine. Film growth occurred in a stepwise manner, as demonstrated by characterization of the zeta potentials and fluorescence intensities of film-coated particles during film assembly. Characterization of film-coated particles by confocal fluorescence microscopy and scanning electron microscopy (SEM) revealed the multilayered particle coatings to be smooth, uniform, and free of large-scale physical defects. Film-coated microparticles sustained the release of transcriptionally active DNA into solution for approximately three days when incubated in physiologically relevant media. Past studies have demonstrated that the adsorption of DNA onto the surfaces of cationic microparticles can be used to target the delivery of DNA to antigen-presenting cells. As a first step toward the application of this layer-by-layer approach to the development of methods for the delivery of DNA to antigen-presenting cells, we demonstrated that film-coated microparticles could be used to transport DNA into macrophage cells in vitro using a model mouse macrophage cell line. Our results suggest the basis of a general approach that could, with further development, prove useful for the delivery of DNA-encoded antigens to macrophages, or other antigen-presenting cells, and provide new materials-based methods for the formulation and delivery of DNA vaccines.

A paradigm for peptide vaccine delivery using viral epitopes encapsulated in degradable polymer hydrogel capsules

“…A promising system for biomedical applications is based on colloidal capsules prepared by the layer-by-layer (LbL) adsorption of polymers onto sacrificial template particles [14,15]. This method provides control over the size of the capsules (from tens of nanometres [16][17][18] to several microns [19]), allows the use of biocompatible [20] and biodegradable [20,21] polymeric building blocks, and enables the engineering of capsules to respond to temperature [22], light [23][24][25] and pH [26]. Recent reports of LbLassembled capsules have demonstrated their utility in applications ranging from drug delivery [27], targeting [28] and sensing [29,30] to the creation of microreactors [31,32] and artificial cells [33].…”

An influenza virus-inspired polymer system for the timed release of siRNA

“…The accumulation of cationic species could result in unwanted toxicity especially when administered in multiple doses. To overcome the release problem of siRNA, polymers have been designed to incorporate side chain molecules that trigger a release when stimulated using temperature 23 , pH 24 , redox potential 25,26 , light 27 , electrical pulse 28,29 and enzymatic degradation 30,31 . Such release mechanisms rely on either external (remote) or environmental stimuli.…”

Multilayered thin films from poly(amido amine)s and DNA

“…Due to the inherent properties of DNA as a natural biological compound, multilayers containing DNA have been investigated for their possibility of providing relatively low-immunogenic coatings [3] and surface-mediated cell transfection on various substrates [4][5][6][7]. Multilayers containing a top DNA layer have shown a significant increase in primary rat dermal fibroblast proliferation as compared to non-coated glass surfaces in vitro, while in vivo tissue response studies also showed that the DNA-coatings are histocompatible without showing signs of inflammation or adverse reactions [3].…”