RESUMO
Poly(ethylene oxide) (PEO) was immobilized by the Williamson ether synthesis onto halogenated surfaces such as poly(vinylidene chloride), surface-brominated polypropylene, and surface-brominated poly(ethylene terephthalate). PEO (Mw 20,000) was converted to its sodium salt and reacted for various times with the halogen-containing surfaces at 95 degrees C in the melt, or as a solution in 2-methoxyethyl ether. X-ray photon spectroscopy and water contact-angle measurements confirmed the surface-immobilization of PEO. The adsorption from phosphate buffer of human serum albumin, immunoglobulin G (IgG) and fibrinogen, and murine IgG was reduced after modification of the surfaces. In addition, IgG adsorption from pooled human sera was diminished. The difference in protein adsorption between test samples and controls exhibited a strong dependence on input protein concentration.
Assuntos
Materiais Biocompatíveis , Polietilenoglicóis , Adsorção , Animais , Materiais Biocompatíveis/química , Fibrinogênio , Humanos , Imunoglobulina G , Técnicas In Vitro , Teste de Materiais , Camundongos , Polietilenoglicóis/química , Polietilenotereftalatos/química , Polipropilenos/química , Polivinil/química , Ligação Proteica , Albumina Sérica , Propriedades de SuperfícieRESUMO
The loss of 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) from solution was studied using fluorescence polarization immunoassay (FPIA) technology and x-ray photoelectron spectroscopy (XPS). Several materials (glass, silylated glass, high density polyethylene, polypropylene, polystyrene, polymethylmethacrylate, Teflon, and Kynar) were studied along with three solvents (water, urine, and Abbott cannabinoids diluent). THC-COOH losses ranging from 0 to 9.7 ng/cm2 and concentration reductions to 46% of starting values were measured. XPS indicated the presence of fluorine-labeled THC-COOH at materials surfaces. A half-life of 10 min was calculated for THC-COOH loss from urine stored in high density polyethylene at room temperature. Sample handling losses during pipetting were determined and ranged from 1.1 to 7.9 ng per aliquot. The effects of sample volume and sample handling on the THC-COOH concentrations of controls were also investigated.
