RESUMO
A new metal-affinity sorbent based on lanthanum stearate monolayers has been developed and characterized. The prospect of its application to specific extraction of organophosphorous compound (OP) adducts of blood proteins was demonstrated. For this, the patterns of soman adducts of human serum albumin (HSA) were comprehensively characterized by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS).
Assuntos
Lantânio/química , Albumina Sérica Humana/química , Soman/química , Estearatos/química , Adsorção , Adulto , Humanos , Masculino , Pessoa de Meia-Idade , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
The purpose of this work was an optimization of polylactide film surfaces designed for human keratinocytes cultivation. The polylactide films were coated by collagen 1. The experiments showed that uniform covering of polymer surface by collagen, and formation of different collagen structures depend on the mode of the protein application. The differences in collagen distribution on the polymer surface influened the keratinocytes growth in culture. Analysis of keratinocytes alignment, as well as cytoskeleton organization demonstrated that fibrillar collagen promoted more even keratinocytes distribution in comparison with the distribution on molecular collagen.
Assuntos
Colágeno Tipo I/metabolismo , Poliésteres/metabolismo , Pele Artificial , Engenharia Tecidual/métodos , Implantes Absorvíveis , Materiais Biocompatíveis/metabolismo , Adesão Celular , Proliferação de Células , Células Cultivadas , Humanos , Queratinócitos/citologia , Queratinócitos/fisiologiaRESUMO
The influence of polylactic acid (PLA) surface films on the pattern of cell behavior was studied. The human dermal fibroblasts were cultivated on PLA covered glasses. The hydrophobic nature of PLA films depends on the availability of polymer solvent in the film preparation. PLA films obtained from a more polar solvent--aceton--appeared to be more hydrophilic than those obtained from methylene chloride. More hydrophilic polymer films also appeared to be more preferable for cell cultivation, and human dermal fibroblasts demonstrated a better adhesion and proliferation on hydrophilic rather than on hydrophobic PLA films.
Assuntos
Materiais Biocompatíveis/metabolismo , Teste de Materiais , Acetona , Materiais Biocompatíveis/química , Materiais Biocompatíveis/normas , Adesão Celular , Células Cultivadas , Fibroblastos/fisiologia , Humanos , Interações Hidrofóbicas e Hidrofílicas , Ácido Láctico/química , Ácido Láctico/metabolismo , Ácido Láctico/normas , Cloreto de Metileno , Poliésteres , Polímeros/química , Polímeros/metabolismo , Polímeros/normas , Pele , SolventesRESUMO
The dynamic surface elasticity of aqueous solutions of poly(N-isopropylacrylamide) (pNIPAM) has been measured by the oscillating barrier and capillary wave methods as a function of time and concentration. While the real and imaginary parts of the surface elasticity almost did not change with the concentration, their kinetic dependencies proved to be nonmonotonic. Simultaneous measurements of the film thickness and adsorbed amount by null-ellipsometry showed that the pNIPAM adsorption can be divided into two steps corresponding to the formation of a concentrated narrow region close to the air phase and a region of tails and loops protruding into the bulk liquid. The local maximum of the elasticity can be observed in the course of the first step when the adsorbed macromolecules do not form long loops and tails. The results are in agreement with recent data on the nonequilibrium surface properties of solutions of other nonionic homopolymers and the theory of dilational surface viscoelasticity.
RESUMO
A review of recent results on the dilational surface viscoelastic properties of aqueous solutions of non-ionic polymers is given. In the frequency range from 0.001 up to 1000 Hz the methods of transverse and longitudinal surface waves and the oscillating barrier method were applied. Viscoelastic behavior of adsorbed polymer films significantly differs from the behavior of films formed by only conventional surfactants of low molecular weight. For example, the dynamic surface elasticity of the former systems is low and almost constant in a broad concentration range. One can observe the increase of the surface elasticity only at extremely low concentrations and/or in the range of semi-dilute solutions. If the surface stress relaxation in conventional surfactant solutions is usually determined by the diffusional exchange between the surface layer and the bulk phase, the relaxation processes in the polymer systems proceed mainly inside the surface layer. Possible mechanism of the latter relaxation is discussed.
