Screen-printed graphite microbands as a versatile biosensor platform

• The use of extremely small working electrodes offers a variety of benefits for electroanalysis. The enhanced mass transport as a result of convergent diffusion is the most important advantage of microdimensional electrodes and results in improved of analytical performance The low detectable-currents problem can be solved by single microelectrode multiplication into an array, thus combining the advantages of enhanced mass transport and high output signals. The microband is one of the most cost-effective and easy-fabricated geometries for microelectrodes. The microband width is a critical microscopic dimension of the electrode, which maintains the dominance of convergent diffusion, whereas the microband length is macroscopic and ensures registration of high currents.Graphite screen-printing on a plastic support is a standard technology for large-scale production of low cost electrochemical devices. This has been combined with simple guillotine cutting to fabricate of microband arrays for autonomous environmental and clinical monitoring.Single-layer and multilayer microband arrays of different band lengths were produced and characterised using optical and electrochemical methods. The critical dimension for the microband width to facilitate convergent diffusion was assessed electrochemically and found to be in the order of 5 microns. The developed electrode structures were used as a versatile platform for the manufacture of model electroanalytical systems. Direct oxidation of ascorbic acid was explored at the microband arrays and a glucose biosensor based on mediated and immobilised glucose oxidase was fabricated. Both examples yielded significant enhancement of the analytical performance.A: the layout of the screen-printed graphite microband array of 5 electrode layers. B: voltammmetric responses obtained at the microband arrays.Acknowledgement: Formas and Security Link for financial support; David Nilsson (Acreo) for screen-printing.

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