Publications by authors named "Joao Batista M Rocha Neto"

The self-assembled layer-by-layer technique has attracted a great deal of attention as a method for engineering bio-functional surfaces under mild chemical conditions. The production of multilayer films, starting from newly designed building blocks, may be laborious, considering the inherent limitations for anticipating how minimal changes in the macromolecular composition may impact both film deposition and performance. This paper presents an automated, high-throughput approach to depositing polyelectrolyte multilayers (PEMs) in multiwell plates, enabling the screening of nearly 100 film formulations in the same process.

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This study presents the axial molar composition of polysaccharide-based polyelectrolyte multilayer (PEM) films loaded with silver ions for antimicrobial applications. Individual polymers (chitosan, hyaluronan or alginate) and silver composition were determined using X-Ray Photoelectron Spectroscopy coupled with C cluster ion sputtering technique, while the influence of silver loading on film topography was assessed using Atomic Force Microscopy. Despite the use of the layer-by-layer approach for film assembly, these PEM films present a non-stratified, nanoblend-like, polymer composition, with a nearly uniform metal distribution over the axial direction.

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The layer-by-layer film deposition is a suitable strategy for the design and functionalization of drug carriers with superior performance, which still lacks information describing the influence of assembly conditions on the mechanisms governing the drug release process. Herein, traditional poly(acrylic acid)/poly(allylamine) polyelectrolyte multilayers (PEM) were explored as a platform to study the influence of the assembly conditions such as pH, drug loading method, and capping layer deposition on the mechanisms that control the release of calcein, the chosen model drug, from PEM. Films with 20-40 bilayers were assembled at pH 4.

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Since chitosan presents the ability to interact with a wide range of molecules, it has been one of the most popular natural polymers for the construction of layer-by-layer thin films. In this study, depth-profiling X-ray photoelectron spectroscopy (XPS) was employed to track the diffusion of sulfonated polystyrene (SPS) in carboxymethyl cellulose/chitosan (CMC/Chi) multilayers. Our findings suggest that the CMC/Chi film does not constitute an electrostatic barrier sufficient to block diffusion of SPS, and that diffusion can be controlled by adjusting the diffusion time and the molecular weight of the polymers that compose the CMC/Chi system.

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