Paper-based biosensors: when paper becomes a huge resource in electrochemistry.

The paper-based colorimetric assays have been widely reported in literature being cost-effective, not requiring additional components (i.e. pump) for microfluidic handling of the solution, and avoiding the sample treatment thanks to the filtering property of the paper. In the last decade, the electroanalysis has discovered the utility of using paper as electrode-active support, converging the reported advantages of paper with the features of electroanalysis such the high sensitivity, selectivity, and the capability to work in complex matrices (e.g. coloured samples).