Enzyme-Polymer stickers for assembling single and multi-analyte biosensors

Electrochemical biosensors have achieved widespread commercial success due to their high selectivity, ease of use, and low cost. However, the fabrication of many such systems, especially when targeting multianalyte sensing, is often constrained by the preparation of the sensing film, which typically relies on drop-casting a polymer–enzyme solutions followed by drying to form the active layer. Depending on the enzyme-polymer formulation, this step can be difficult to integrate into large-scale, roll-to-roll production processes and lacks flexibility for constructing multianalyte sensors. Here, we propose a new fabrication concept in which the sensing film is produced separately as transferable sensor stickers. These stickers contain enzymes and redox polymers and can be transferred in a single step either onto singular electrodes to generate single-analyte sensors or combined on electrode arrays for multianalyte sensing. We demonstrate the sensor sticker concept using four oxidoreductases as biorecognition elements that catalyze the oxidation or reduction of four different analytes (H₂, HCOONa, KNO₃, and NADPH). Accurate sensing was achieved on both standard glassy carbon electrodes and on specifically designed microelectrode arrays modified with the sensor stickers. The stickers exhibited high selectivity with minimal interference, even in mixed samples containing all four analytes. This modular approach to assembling multianalyte sensors on microarrays is broadly applicable to other analytes and holds strong promise for flexible, customizable, and scalable fabrication of multianalyte biosensors.