The effect of Amaranth oil on monolayers of artificial lipids and hepatocyte plasma membranes with adrenalin-induced stress.

In this paper the oil from seeds of Amaranthus cruentus L. (AmO) was shown to be an efficient modulator of the physical chemical properties of artificial lipid and rat hepatocyte plasma membranes. AmO improved the membrane stability, their stress resistance and the adsorption of neurotensin to plasma membranes with the distinct biphasic interactions being observed even after adrenalin stress exposure. The analysis of pro-/antioxidant balance in rat blood revealed a mild prooxidant activity after AmO intake, which was accompanied by accumulation of oxidative destruction products in plasma membranes. This prooxidant action of AmO was corroborated in vitro in an adrenalin autooxidation model. On the other hand, the observed improved resistance to adrenalin stress in AmO supplemented rats was associated with an antioxidant response in blood and plasma membrane studies. The AmO effects can be attributed to the modulation of the metabolic pathways involved into oxygen and free radical homeostasis.

Colorimetric test-systems for creatinine detection based on composite molecularly imprinted polymer membranes.

An easy-to-use colorimetric test-system for the efficient detection of creatinine in aqueous samples was developed. The test-system is based on composite molecularly imprinted polymer (MIP) membranes with artificial receptor sites capable of creatinine recognition. A thin MIP layer was created on the surface of microfiltration polyvinylidene fluoride (PVDF) membranes using method of photo-initiated grafting polymerization. The MIP layer was obtained by co-polymerization of a functional monomer (e.g. 2-acrylamido-2-methyl-1-propanesulfonic acid, itaconic acid or methacrylic acid) with N, N'-methylenebisacrylamide as a cross-linker. The choice of the functional monomer was based on the results of computational modeling. The creatinine-selective composite MIP membranes were used for measuring creatinine in aqueous samples. Creatinine molecules were selectively adsorbed by the MIP membranes and quantified using color reaction with picrates. The intensity of MIP membranes staining was proportional to creatinine concentration in an analyzed sample. The colorimetric test-system based on the composite MIP membranes was characterized with 0.25 mM detection limit and 0.25-2.5mM linear dynamic range. Storage stability of the MIP membranes was estimated as at least 1 year at room temperature. As compared to the traditional methods of creatinine detection the developed test-system is characterized by simplicity of operation, small size and low cost.