Hemocompatibility of Silicon-Based Substrates for Biomedical Implant Applications

Silicon membranes with highly uniform nanopore sizes fabricated using microelectromechanical systems (MEMS) technology allow for the development of miniaturized implants such as those needed for renal replacement therapies. However, the blood compatibility of silicon has thus far been an unresolved issue in the use of these substrates in implantable biomedical devices. We report the results of hemocompatibility studies using bare silicon, polysilicon, and modified silicon substrates. The surface modifications tested have been shown to reduce protein and/or platelet adhesion, thus potentially improving biocompatibility of silicon. Hemocompatibility was evaluated under four categories—coagulation (thrombin–antithrombin complex, TAT generation), complement activation (complement protein, C3a production), platelet activation (P-selectin, CD62P expression), and platelet adhesion. Our tests revealed that all silicon substrates display low coagulation and complement activation, comparable to that of Teflon and stainless steel, two materials commonly used in medical implants, and significantly lower than that of diethylaminoethyl (DEAE) cellulose, a polymer used in dialysis membranes. Unmodified silicon and polysilicon showed significant platelet attachment; however, the surface modifications on silicon reduced platelet adhesion and activation to levels comparable to that on Teflon. These results suggest that surface-modified silicon substrates are viable for the development of miniaturized renal replacement systems

ANTIPRODUCTION: PROBLEM OF METAL QUALITY

The most typical examples of defective metallurgical products, presented for analysis to the sector of metallographic and X-ray-structural analysis of FTl NAN of Belarus are examined

DETERMINATION OF OXYGEN CONTENT IN COPPER BY MEANS OF COMPUTER ANALYSIS OF IMAGES

The possibility of determination of oxygen concentration in cast copper in program «IMAGE SP» is considered. It is shown the satisfactory compliance with results, received under state standard specification 13938.13-93. The advantages of computer methods of analysis are demonstrated

POWDER-GAS DISCHARGE, FORMED AT MELTING OF ALUMINIUM CASTING ALLOYS IN INDUCTION CRUCIBLE FURNACE IAT- 6

The carried out analysis of powder-gas discharge shows that volumes and composition of the forming dust are determined by composition of recycled material, type of lubrication for machines under high pressure, quality of recycled material preparation and technology of refining processing

Influence of casting mode on the structure and physical characteristics of sacrificial zinc anodes

The article presents the results of investigation of structure, specific weight, electrical conduction and thermoelectromotive force of zinc strands manufactured by chill casting and by continuous casting, as well as by rolling of ingots and thin block casting^. Solubility of zinc anodes produced in this way in electroplating baths is studied

INVESTIGATION OF POWDER-GAS EMISSIONS, FONNED AT MELTING AND REFINING OF ALUMINIUM ALLOYS IN REVERBERATING FURNACES

As a result of carried out analysis of processes of aluminium alloys casting and refining in reverberating  furnaces it is determined that searching source of harmful emissions are the refining processes

INFLUENCE OF MELTING TECHNOLOGY IN SHORT-FLAME ROTOR FURNACE ON COMPOSITION OF POWDER-GAS EMISSIONS

It is shown that processes of unprepared recycled material melting and of refining processing make ecological danger. That is why one of the variants of ecological safety of refining processes is development and application of more low-toxic preparation and refining alloys

INCREASING OF ECOLOGICAL SAFETY OF THE PROCESSES OF SILUMINS REFINING DUE TO APPLICATION OF LOW-TOXIC FLUX METALS AND PREPARATIONS

It is shown that the received complex of mechanical and technological characteristics of alloy AK9 after processing of melt with investigated fluxes and preparations can be recommer ded for use in plant conditions that will enable the increase of ecological safety of color-founding production

PECULIARITIES OF POWDER-GAS FORMATION AT REFINING OF ALUMINIUM ALLOYS BY CHLORINECONTAINING COMPOUNDS

The peculiarities of powder-gas formation at refining of aluminium alloys with chlorine-containing combinations are considered