Improvement of urease based biosensor characteristics using additional layers of charged polymers Original Research Article

Enzymatic sensors with urease immobilized on the surface of ion sensitive field effect transistors (ISFETs) were developed. Covering the immobilized enzyme with a charged polymer layer increases sensitivity and stability of the urea specific biosensor. Urease immobilization under a negatively charged polymer induces an increase of the inhibition effect of the heavy metal ions due to the cation accumulation in the polymeric matrix. On the other hand a positively charged additional membrane protects the bioselective material from positively charged heavy metal ions. Such developed enzymatic biosensors can be used for the analysis of trace levels of heavy metal ions in water samples through inhibition mechanisms. Thus, the concentrations of some heavy metal ions as low as 1 μM and lower can be detected.