RESUMEN
The aim of present study was to determine the hemocompatibility, cellular response of endothelial cells and bacterial adhesion to a new polyester nanocomposite. The carbon nanoparticle nanocomposite was prepared via in situ polymerization of monomers to obtain material of hardness 55 Sh D similar to polyurethanes used in medical applications, for example, in heart-assisting devices. The carbon nanoparticle-containing polyester exhibits markedly reduced bacterial colonization, as compared to commercially available polyurethanes. Further the nanocomposite possesses markedly improved hemocompatibility, as determined by flow cytometry, and robust endothelialization. Possible explanations for these beneficial properties include surface nanoroughness of carbon nanoparticle-containing nanocomposites and presence of fatty acid sequences within polymer structure.
Asunto(s)
Materiales Biocompatibles/química , Carbono/química , Nanocompuestos/química , Nanopartículas/química , Poliésteres/química , Adhesión Bacteriana , Carbono/metabolismo , Adhesión Celular , Escherichia coli , Ácidos Grasos/química , Células Endoteliales de la Vena Umbilical Humana/citología , Humanos , Ensayo de Materiales , Nanocompuestos/microbiología , Nanocompuestos/toxicidad , Poliésteres/metabolismo , Poliuretanos/química , Propiedades de SuperficieRESUMEN
We demonstrate here for the first time the relationship between electron work function of metallic substrate material, used for coating with thin dielectric carbon (DC) film, and surface thrombocompatybility of this structure. Thin dielectric layers of DC, with thickness below 1 microm, were deposited on medical steel 316L, titanium alloy Ti6Al4V and titanium nitride (TiN) using the RFCVD method. The values of the DC coated metallic electrode potential in water and in serum and the number of adhered blood platelets to the DC coated metals depended on the electron work function (phiM) of the metallic substrate. As the phiM increased, the electrode potentials increased, whereas the number of adhered blood platelets decreased. This effect permits controlling the interaction between blood and the thin DC films by selecting an appropriate metallic substrate.
RESUMEN
Microscopic methods usable for sample surface imaging and subsequent qualitative and quantitative evaluation of platelet adhesion to the surface of the biomaterial studied were compared. It was shown, making use of the samples of medical steel (AISI 316L), that such tools as surface imaging with scanning electron microscopy (SEM), glutaraldehyde induced fluorescence technique (GIFT) and metallurgical microscopy (MM) are equivalent in evaluating surface platelet adhesion. The importance of biological variability of blood samples for a proper result assessment and the necessity of using internal standards were also considered.
Asunto(s)
Materiales Biocompatibles/metabolismo , Microscopía/métodos , Adhesividad Plaquetaria/fisiología , Materiales Biocompatibles/farmacología , Plaquetas/efectos de los fármacos , Plaquetas/ultraestructura , Humanos , Adhesividad Plaquetaria/efectos de los fármacos , Acero/farmacología , Propiedades de Superficie/efectos de los fármacosRESUMEN
The aim of the present work was to examine the interactions of parylene C with such selected biological objects as: blood plasma proteins, platelets, endothelial cells, and bacterial biofilm produced by E. coli cells. The results obtained strongly support the thesis that parylene C is a material worth considering for biomedical use. Parylene C coating on polished medical steel significantly reduces platelet adhesion to this surface. On the other hand, in the case of the surface of machined medical steel coated with parylene C, the number of adhered platelets is significantly higher. This also means that surface texture of substrate material is very well reproduced by parylene C coating and is an important factor facilitating the platelet adhesion. Adsorption of plasma proteins at parylene C surface is very effective, and this finding confirms a notion that cell interaction with surfaces is mediated by the adsorbed proteins. In the light of the above, a high susceptibility of parylene C surface to bacterial colonization is easy to explain. The results showing reduced proliferation and changes in endothelial cell gene expression should also be seriously analysed when parylene C is considered for the use in contact with blood vessels.
Asunto(s)
Materiales Biocompatibles , Polímeros , Xilenos , Adsorción , Adhesión Bacteriana , Materiales Biocompatibles/química , Proteínas Sanguíneas/metabolismo , Adhesión Celular , Línea Celular , Materiales Biocompatibles Revestidos , Células Endoteliales/citología , Escherichia coli/fisiología , Humanos , Técnicas In Vitro , Ensayo de Materiales , Adhesividad Plaquetaria , Polímeros/química , Acero Inoxidable , Propiedades de Superficie , Xilenos/químicaRESUMEN
Comparative analysis of the protein profile of blood platelets isolated from nondialyzed and hemodialyzed uremic patients and healthy controls has been performed. These preliminary results indicate markedly changed expression of several proteins in blood platelets from both groups of patients compared with controls, with dramatic changes in hemodialyzed patients in the over-expression of low molecular peptides with a very wide range of pI values.
