Monodisperse Polyelectrolyte‐Supported Asymmetric Lipid‐Bilayer Vesicles

Abstract

Cataposit 44 (Shipley) in water. After 10 min the fibers were recovered by filtration and suspended in a wash solution of Cataprep 404. Filtration was repeated and followed with 4 washes with 1 L of water. The final filter cake was freeze-dried to yield a fine light-gray powder. The electroless copper-plating bath was Fidelity 1025. Dry fibers were added at the concentrations specified in the text and subjected to continuous stirring. Once exhausted the reaction mixture was filtered, and the fibers washed copiously with water and freeze-dried.Absolute density was determined by water displacement. A known mass of fibers was placed in a pre-weighed graduated cylinder. Water was added to a total known volume (bubbles were removed by subjecting the cylinder to vacuum). The volume of water was determined by re-weighing the cylinder. The volume occupied by the fibers was determined by subtracting the volume of water from the total volume.An approximation of the conductivity of the metal plated onto cellulose was determined by use of a Spectra/Por cellulose membrane (Spectrum) as a surrogate material. Measurement of the conductivity of individual fibers is impractical, and the conductivity of bulk fiber is dominated by contact resistance. A membrane of 10 mm width and 8.5 cm long was plated with electroless copper essentially as described above. The final thickness was 30.5 lm, with a copper layer on both sides of less than 100 nm (as determined by weight gain). The resistance of this membrane was 3.5 X, which corresponds to a conductivity of 8.1 10 5 X ±1 m ±1 . Sample composites were fabricated by adding the requisite mass of fibers to polyurethane LS-40 (BJB Enterprises) to yield the desired volume percentage. Moldings were made between two flat plates, with shims to determine the thickness. Samples were cured for 24 h at room temperature. Electromagnetic measurements were conducted with a Hewlett-Packard 8510 Network Analyzer and permittivities were calculated by the Nicholson-Ross technique [14]. Samples were 1.27 mm thick and toroidal, with an inner diameter of 3 mm and an outer diameter of 7 mm and measured in a coaxial cable arrangement.DC conductivity of the composites was measured across the thickness of the samples (1.27 mm) between metal plates of 5 cm by 1.8 cm in dimension. Measurements were made with a Keithley 194 A Digital Multimeter. The limit of detection was approximately 3 10 ±10 X ±1 m ±1 .

Novel Engineered Ion Channel Provides Controllable Ion Permeability for Polyelectrolyte Microcapsules Coated with a Lipid Membrane

“…An easier and proven way to ensure that the microcapsules do not stimulate an immune response is coating the polyelectrolyte with phospholipid membranes. [4][5][6][7][8] A further advantage of this approach is the possibility to incorporate biomolecules such as membrane transport proteins in the supported phospholipid membranes, as has been explored recently by several groups [9,10] and reported in this paper. The…”

Stimuli‐Responsive Multilayered Hybrid Nanoparticle/Polyelectrolyte Capsules

“…Recently, this technique has been applied for the fabrication of tiny three-dimensional microstructures, called hollow polyelectrolyte capsules, by LbL coating of a sacrificial template followed by the dissolution of this template. [8,9] Due to the multifunctionality of the LbL technique, it is possible to fabricate tailor-made capsules with functionalized [10,11] or stimuli-responsive [12,13] walls which could be promising for drug-delivery applications. [14,15] Nanoparticle-containing capsules have already been reported in literature, although in all cases the number of nanoparticle layers was limited to one [16] or the nanoparticles were introduced (e.g., by synthesis within the capsule wall) after the fabrication of the capsules.…”

Enzyme-Encapsulated Layer-by-Layer Assemblies: Current Status and Challenges Toward Ultimate Nanodevices

“…Katagiri and Caruso applied step-by-step LbL assembly to preparation of lipid bilayer vesicles with asymmetric structures between inner and outer shells [251]. They first assembled polyelectrolyte multilayers on melamine-formaldehyde particles and terminated the assembly with negative outermost surfaces.…”