Polyelectrolyte Capsules with Tunable Shell Behavior Fabricated by the Simple Layer-by-Layer Technique for the Control of the Release and Reactivity of Small Guests

Abstract

A novel simple protocol for the layer-by-layer coating of uncharged organic substrates (hydrophobic carboxylic acid esters, CAEs) and control of their loading/release behavior has been developed. The approach involves the preliminary treatment of CAEs with the cationic surfactant cetyltrimethylammonium bromide followed by poly(acrylic acid)/polyethyleneimine alternate deposition. The basic hydrolysis of the substrates is used to spectrophotometrically control the loading/release behavior through monitoring the absorbency of the reaction product p-nitrophenolate ion. Unlike the reactivity of free CAEs, highly sensitive to the solution pH, and the presence of micellar catalysts, the reaction rate of the loaded substrates is unaffected by reaction conditions and can be administered by the capsule design (numbers of deposition cycles, adjusted pH, ultrasonication). The developed protocol makes it possible to omit the use of the sacrificial template and stages of its removal. Capsules corresponding to the biorelevant size criterion, with diameter of ≤200 nm, are obtained. They can be successfully applied for sustaining the dosage of different specimens with the desirable rate and for the control of the guest reactivity by tuning the shell permeability.

Spectroscopic Study of the Interaction of Carboxyl-Modified Gold Nanoparticles with Liposomes of Different Chain Lengths and Controlled Drug Release by Layer-by-Layer Technology

“…Such behavior is assumed to occur at the outset of coating (for the initial layers), which is generally characterized by an inconsiderable increase in the shell thickness. 79 DLS measurements and the zeta potential give results following a similar pattern for DMPC and DLPC also, as shown in the Supporting Information (SI Table 1). We characterized the morphology of the obtained capsule structures with SEM imaging (Figure 6), which reveals that the capsules have a uniform size of around 150 nm.…”

Organometallic Polymer Electrolyte Membrane Fuel Cell Bis‐Ligand Nickel(Ii) Complex of 1,5‐Di‐P‐Tolyl‐3,7‐Dipyridine‐1,5,3,7‐Diazadiphosphacyclo‐Octane Catalyst

“…Atomic force microscopy (AFM) is a convenient method for visualizing the morphological characteristics in the nanoscale range of soft supramolecular formations, monolayers, and polymer systems on atomically smooth substrates. To study the shape of the organometallic catalysts’ particles immobilized on the carbon substrate the catalysts were deposited on an atomically smooth surface of pyrolytic graphite (Figure A).…”

“…[11] In aP EMFC using Ni(Py-p-Tol)/C at the anode withouta ny CNTs and stitching procedures to them and Pt/C at the cathode the powerd ensity reached 14.66 mW cm À2 ,w hich is at the level of the best known analog with CNTs. [13] Atomic force microscopy( AFM)i saconvenient method for visualizing the morphological characteristics in the nanoscale range of soft supramolecular formations, [17][18][19] monolayers, [20,21] and polymer systems [22,23] on atomically smooths ub-strates.T os tudy the shape of the organometallic catalysts particles immobilized on the carbon substrate the catalysts were depositedo na na tomically smooth surface of pyrolytic graphite (Figure 2A). Thea ggregates with ah eight of af ew nanometers ( Figure 2B)a nd al ateral size of about 240 nm ( Figure 1C)a re typical for the compound Ni(Py-p-Tol).…”

Self-Assembling Drug Formulations with Tunable Permeability and Biodegradability

“…This approach has been used in the layer-by-layer protocol, in which a micellar core composed of cationic surfactants was used as a template for the deposition of polyanion/polycation pairs. In this case, multiple tasks can be achieved: (i) hydrophobic guest solubilization; (ii) stabilization of a micellar nanocontainer loaded with drug or probe; (iii) the electrostatic promotion of adsorption of the first oppositely charged polyelectrolyte layer [95][96][97][98].…”