Comparative analysis of human serum albumin adsorption and complement activation for intraocular lenses.

Intraocular liquid, in contrast to blood, has no cellular components; therefore, proteins (human serum albumin [HSA], and [alpha, beta, gamma] globulins) are the major components that determine patients' response to the intraocular lens (IOL) surface. In addition to the amount of adsorbed proteins, the possibility of its conformational changes, including conformational changes of globulins C1 and C3 that respond for the activation of the complements system by the classical and alternative pathways, cannot be excluded. The interaction between IOLs and protein components of intraocular liquid directly influences the ocular exudative reaction in the early postoperational period, the intensity of cellular and pigmental scurf on the surface of the IOLs, and the state of endothelial cells of the cornea in the distant postoperational period. Our goal was to compare the interaction of commercial IOLs made from polymethylmethacrylate, silicone, poly-2-hydroxyethyl methacrylate (p-HEMA), and copolymer p-HEMA with collagen with HSA and the complement system. The total internal reflection fluorescence (TIRF) method and hemolytic assay were used for this task, respectively. It has been demonstrated that the probability of biocompatibility of commercially produced IOLs on the stage of protein adsorption can be evaluated using the kinetic of HSA-fluorescein isothiocyanate adsorption onto the IOL surface by the TIRF METHOD: In the case of IOLs from p-HEMA, a negative correlation was shown between the degree of irreversible adsorption of HSA and the minimum relative rate constant of the surface-induced complement activation. We did not find any correlation between hydrophilicity/hydrophobicity of lenses and their adsorptional properties including complement activation. From suggested adsorptional criteria in vitro for biocompatible surfaces, the hydrogel lens from p-HEMA has a lower probability of biocompatibility in comparison with other IOLs.

Carbon coated polyethylene: effect of surface energetics and topography on human platelet adhesion.

The influence of surface energy and structural properties of carbon coated polyethylene (PE) on the human platelet adhesion was studied. Three types of amorphous carbon coating were obtained by plasma pulse discharge, with the number of pulses grading as 10, 50, 100. Human serum albumin adsorption experiments have been carried out with all samples in vitro. Platelet adhesion analysis by SEM included determination of total quantity of adherent platelets, and respective quantities of platelets at different stages of activation (single, spread, aggregates). Surface topographies ranged from bare PE and such (10 pulses), to globular 0.5 microm in size (50 pulses), and complex fibrillar 3-4 microm structures (100 pulses). Surface free energy varies from 31.7 +/- 0.6 to 40.4 +/- 0.6 mN/m for uncoated PE and 10 pulse coatings, respectively, as determined by contact angle techniques. All studied coatings demonstrate weaker platelet activation properties in comparison with untreated PE. Among all studied coatings, the 50 pulse coated surface seems to be the least suitable for contact with platelets, mainly due to its structural rather than to its energy properties. These data are related to a sharp decrease in the adsorbed protein level for the samples with 50 pulse coatings. The applied analysis of platelet activation enables more accurate characterization of platelet-biomaterial interaction.

[Competitive adsorption of human fibrinogen on an amorphic quartz surface]. / Konkurentnaia adsorbtsiia fibrinogena cheloveka na poverkhnosti amorfnogo kvartsa.

The kinetics of adsorption of fibrinogen on the surface of amorphous quartz from binary solutions containing human serum albumin and gamma-globulin was studied by the method of fluorescence of total internal reflection. A model of energetically nonhomogeneous interactions in the surface/protein system was used to explain the mechanism of competitive adsorption of proteins.

[Use of the fluorescence method in the study of protein adsorption onto the surface of intraocular lenses]. / Primenenie metoda fliuorestsentsii dlia issledovaniia adsorbtsii belkov na poverkhnosti intraokuliarnykh linz.

The paper shows it possible to use the method of total internal reflection-fluorescence for study of the kinetics of protein adsorption onto the surface of intraocular lenses (IOL) made from optically transparent hydrophobic polymers and hydrogels. The nature of the materials (polymethylmethacrylate, silicone, p-HEMA, p-HEMA-collagen copolymer) used for IOL on the adsorption and desorption of human serum albumin was studied.