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Multilayered Films (multilayered + film)
Selected AbstractsConstruction of Polyethyleneimine-,-cyclodextrin/pDNA Multilayer Structure for Improved In Situ Gene Transfection,ADVANCED ENGINEERING MATERIALS, Issue 1-2 2010Yan Hu This study reports in situ gene delivery from gene-functionalized poly(D,L -lactic acid) (PDLLA, Mw of around 2.0,×,105,g,mol,1) films, which were constructed via layer-by-layer (LbL) assembly technique with low molecular weight polyethylenimine-,-cyclodextrin (PEI-CD) conjugate and plasmid DNA (pDNA). PEI-CD was characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR), respectively. The buildup of multilayered PEI-CD/pDNA pairs onto PDLLA films was monitored with contact angle measurements and UV,Vis spectrometer, respectively. A sustained release of pDNA from multilayered films was observed for 28,h. The mechanism of in situ gene delivery on PDLLA film was investigated in this study as well. Spherical PEI-CD/pDNA complexes were formed and released following the deconstruction of multilayered films, which was confirmed by transmission electron microscopy (TEM) and gel electrophoresis, respectively. Surface mediated in situ gene transfection was achieved when culturing hepatoma G2 (HepG2) and human embryonic kidney 293 (HEK293) onto PEI-CD/pDNA multilayered films. Furthermore, PEI-CD improved the gene transfection efficiency when compared with that of PEI. Such gene-functionalized biomaterial reported here has potential application in tissue engineering and implant technology. [source] Fabrication of Galactosylated Polyethylenimine and Plasmid DNA Multilayers on poly (D,L -lactic acid) Films for in situ Targeted Gene Transfection,ADVANCED ENGINEERING MATERIALS, Issue 5 2009Yan Hu This study presents surface-mediated targeted in situ gene delivery from gene-tagged poly(D,L -lactic acid) (PDLLA) films, which were fabricated via a layer-by-layer (LbL) assembly technique with galactosylated polyethylenimine (GP) and plasmid DNA (pDNA, pSV-,-galactosidase). A linear growth of GP/pDNA multilayered films was observed. The pDNA was continuously released from multilayered films for over 32,h. The multilayered structure degraded and simultaneously formed GP/pDNA complexes in situ when exposing to a physiological environment. The pDNA was well protected by GP against DNase I digestion within formed GP/pDNA complexes. Our results demonstrated that GP contributes to receptor-mediated targeting for cell uptake and in situ gene transfection. The results reported here are potentially important for gene therapy, surface engineering of biomaterials, tissue engineering and implant technology. [source] Biomimetic Surfaces for High-Performance OpticsADVANCED MATERIALS, Issue 46 2009Yunfeng Li High-performance antireflective and antifogging surfaces are fabricated on planar silica substrates and planconvex lenses. Such surfaces dramatically suppress reflection over a large range of wavelengths and a large field of view. Additionally, the ARS surfaces exhibit high-quality superhydrophilic properties. For antireflective and antifogging applications, the ARS surfaces exhibit more high-quality mechanical stability and better durability than multilayered films. [source] Peeling Back the Layers: Controlled Erosion and Triggered Disassembly of Multilayered Polyelectrolyte Thin Films,ADVANCED MATERIALS, Issue 23 2007M. Lynn Abstract Methods for the layer-by-layer deposition of oppositely charged polymers on surfaces can be used to assemble thin multilayered films using a broad range of natural, synthetic, and biologically relevant materials. These methods also permit precise, nanometer-scale control over the compositions and internal structures of multicomponent assemblies. Provided that the individual components of these materials are selected or designed appropriately, these methods provide tantalizing new opportunities to design thin films and coatings that provide spatial, temporal, or active control over the release of one or several different agents from surfaces. The last two years have seen a significant increase in reports describing the development of new chemical, physical, and biomolecular approaches to the controlled erosion, triggered disassembly, or general deconstruction of multilayered polymer films. In this Progress Report, we highlight recent work from our laboratory and several other groups toward the design of ultrathin multilayered assemblies that i),permit broad, tunable, and sophisticated control over film erosion, and ii),provide new opportunities for the localized release of macromolecular therapeutics, such as DNA and proteins, from surfaces. [source] Experimental and modeling analysis of diffusive release from single-shell microcapsulesAICHE JOURNAL, Issue 11 2009Enrique Muñoz Tavera Abstract There is much experimental and mathematical work that describes chemical transport from multilayered films of planar geometries. There is less so, however, for chemical transport from multilayered spheres, a common structure for controlled-release materials. Based on the Sturm,Liouville approach of Ramkrishna and Amundson (1974), explicit analytical solutions for the concentration profiles and release kinetics from spherical capsules are presented. Fluorescent dye-release studies using single-shelled microspheres called nanoparticle-assembled capsules were performed to validate the model for uniformly and nonuniformly sized capsules. The combined experiment-modeling approach allows optical microscopy images and release measurements to be readily analyzed for estimating diffusion coefficients in capsule core and shell walls. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] | ||||||||||