Transferable Enzyme-Polymer Stickers for Modular Assembly of 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 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 introduce a new assembly strategy in which sensing films composed of redox-active polymers and enzymes are pre-fabricated as sensor stickers that can be transferred in a single step either onto individual 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 targeting four analytes: hydrogen, formate, nitrate, and NADPH. Accurate sensing was achieved both on conventional glassy carbon electrodes and on custom-designed microelectrode arrays modified with the sensor stickers. The resulting sensors displayed high selectivity with minimal cross-interference, even in complex mixtures 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.