An amperometric uric acid biosensor based on Bis[sulfosuccinimidyl] suberate crosslinker/3-aminopropyltriethoxysilane surface modified ITO glass electrode

A label free, amperometric uric acid biosensor is described by immobilizing enzyme uricase through a self assembled monolayer (SAM) of 3-aminopropyltriethoxysilane (APTES) using a crosslinker, Bis[sulfosuccinimidyl]suberate (BS3) on an indium-tin-oxide (ITO) coated glass plate. The biosensor (uricase/BS3/AFTES/ITO) was characterized by, scanning electron microscopy (SEM), atomic force microscopy (AFM) and electrochemical techniques. Chronoamperometric response was measured as a function of uric acid concentration in aqueous solution (pH 7.4). The biosensor shows a linear response over a concentration range of 0.05 to 0.58 mM with a sensitivity of 39.35 mu A mM(-1). The response time is 50s reaching to a 95% steady state current value and about 90% of enzyme activity is retained for about 7 weeks. These results indicate an efficient binding of enzyme with the crosslinker over the surface of APTES modified ITO glass plates, which leads to an improved sensitivity and shelf life of the biosensor. (C) 2010 Elsevier B.V. All rights reserved.