Sol-gel technology in enzymatic electrochemical biosensors for clinical analysis

摘要: Enzymes are without question the most powerful, versatile and efficient, wide-spread biocatalysts in biological world, being responsible for remarkable reaction rate enhancements. also very specific, able to discriminate between substrates with quite similar structures. They exhibit different types of selectivity (chemo-, enantio-, regioand diastereoselectivity) can catalyse a broad range reactions. Moreover they environmentally friendly, acting under mild conditions. used many biotechnological domains, as isolated enzymes or whole cells, free immobilized form. The dual character an enzyme, both protein catalyst, brings face special properties proteins like activity, selectivity, inhibition phenomena, unfolding harsh environment need stability, reproducibility, long term reusability catalyst. catalytic activity depends on integrity their native conformation. If enzyme is denatured dissociated into its subunits, usually lost. Thus primary, secondary, tertiary, quaternary structures essential activity. Therefore, cannot be at high temperature, extreme pH ionic strength, operation parameters that could lead deactivation. Another issue limits efficiency enzymatic reactions substrate product – stops working higher and/or concentration (Chibata, 1978; Smith, 2004). So, reliable techniques stabilization great practical importance (Rothenberg, 2008). biosensors “immobilized” Even though beginning 21th century immobilization biomolecules may first glance solved problem, reality shows work has yet done order obtain stable, longliving robust active biocatalysts, even if (enzymes, proteins, nucleic acids), cells other species. A lot methods available. Among them, sol-gel technology application biosensing been interest last two decades. Sol-gel (Brinker & Scherer, 1990) opens simple route produce materials glasses, monoliths, powders, thin films Inorganic hybrid organic-inorganic micro nanostructered matrices based mainly silica gels will briefly described.