Screen-printed disposable urease-based biosensors for inhibitive detection of heavy metal ions

Low-cost and small-size, all-solid-state potentiometric pH-urease electrodes useful for determination of heavy metals ions have been developed by means of screen-printing. The biosensing thick-film is prepared using biocomposite screen-printable material composed of ruthenium dioxide, urease, graphite and organic polymer. Electric circuit and electrode insulation are also fabricated in the same thick-film technology using inexpensive commercially available pastes. All the pastes used for manufacturing of the biosensor are cured under mild conditions not dangerous for the immobilized enzyme and for the plastic flexible foil used as a substrate for screen-printing. The developed enzyme electrodes are useful as disposable potentiometric biotests for selected urease inhibitors. They enable detection of silver and copper ions at sub-ppm levels.