Paper as an ecodesigned and smart material for sample preparation integrated with electrochemical (bio)sensors

Since 2009, paper-based electrochemical biosensors have demonstrated several additional features in analytical chemistry thanks to their capability to manage the fluids by pump-free microfluidics, easily preconcentrate the target analytes, treat the sample with a task-free approach, and detect the target analyte with high sensitivity and accuracy. Herein, we point out the use of paper as a functional material for sample preparation, addressing easily and in a sustainable way the fluid sample management, filtration, separation, centrifugation, chemical sample treatment, and reagent addition. The use of paper for sample preparation in the electrochemical (bio)sensor field is shed light for the first time in a dedicated review. The overriding goal is to highlight the advantages of these cost-effective, environmentally friendly, and easy-to-use devices for smart preparation procedures and accurate electrochemical detection of the target analytes in several fields, including biomedical, environmental, and agrifood.