Screen printed carbon advantages

In an effort to develop a rapid and efficient scheme for immobilizing nucleic acids onto carbon screen-printed transducers, many authors took advantage of the strong adsorptive accumulation of these biomolecules at the screen-printed carbon surfaces. In particular, many of them reported that electrochemical adsorption (adsorption controlled by a positive potential) enhances the stability of the probe and this technique was preferentially chosen. 

An approach similar to the amperometric morphine sensor has very recently been described by Kroger et al. [81]. Particles of poly(EDMA-co-4-vinylpyridine) imprinted with 2,4-dichlorophenoxyacetic acid were trapped in agarose on a screen-printed carbon electrode. The sensor was equilibrated in a solution of the template analyte species with a fixed amount of the electroactive competitor homogentisic acid, then the free homogentisic acid was quantified by differential pulse voltammetry. This approach has the advantage of being applicable to non-redox-active species, provided a suitable redox-active competitive probe can be found. 

Advantages of the Enzyme-Based Electrochemical Genosensors in Detecting Bacteria on Screen-Printed Carbon Chips... 

Pseudohomogenous amperometric displacement immunosensors have also been developed. The displacement assay is performed on a disposable screen printed carbon electrode and takes advantages of the cross-reactivity of some monoclonal antibodies. As an example, the monoclonal anti-2,4-D antibody exhibits a relative cross-reactivity toward immobilized MCPA. In the presence of the target analyte (2,4-D) a displacement effect is observed. Consequently, the peroxidase label of the remaining anti-2,4-D antibodies is detected at the carbon electrode, when adding hydrogen peroxide and potassium iodide as redox mediator, at OV versus Ag/AgCl. 

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