RESUMO
Endotracheal tubes (ETTs) are a common source of bacterial colonization, leading to ventilator-associated pneumonia (VAP). This research developed a biofilm-resistant ETT, following the principles of green chemistry. Using an aqueous layer-by-layer (LbL) technique, a thick polyelectrolyte multilayered film was deposited on a ventilation tube. The polyelectrolyte multilayered film accommodated silver nanoparticles (AgNPs) formed in situ by reducing Ag+ ions with Eucalyptus citriodora leaf extract. The multilayered film coating conformed to the curved surfaces of the ETT. Film thickness and silver content increased exponentially with the number of polyelectrolyte bilayer pairs, and a sufficiently high AgNPs content of 10-30%w/w was obtained at 75 to 125 bilayer films. Adhesion of the Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa was prevented by 99.9 and 99.99%, respectively, without cytotoxic effects against human lung epithelial cells (pâ¯<â¯0.05).
Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Química Verde/métodos , Intubação Intratraqueal , Nanopartículas Metálicas/química , Polieletrólitos/farmacologia , Prata/farmacologia , Células A549 , Morte Celular/efeitos dos fármacos , Forma Celular/efeitos dos fármacos , Humanos , Nanopartículas Metálicas/ultraestrutura , Testes de Sensibilidade Microbiana , Gases em Plasma/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/fisiologia , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Staphylococcus aureus/fisiologia , MolhabilidadeRESUMO
Nanostructured polymeric capsules have been applied in different fields, and specifically are regarded as promising for smart drug delivery applications. The physical-chemical and mechanical properties, and thus the permeability of the polyelectrolyte multilayer shell, play an important role in efficient delivery. Quartz crystal microbalance working in liquid has been used for the characterization of the buildup process and of the viscoelastic properties of biocompatible multilayers and of their functionalization by S-layer proteins. Optical and scanning electron microscopy have been used for the morphological characterization of nanostructured capsules obtained at physiological conditions by the assembly of the characterized multilayers onto spherical cores and by their subsequent removal. The proposed functionalized biocompatible capsules can be regarded as promising candidates for smart drug delivery applications.