Dual role of Prussian blue in polyenzymatic biosensing systems

Prussian blue (PB) films are widely recognized for their exceptional utility in electrochemical and optical enzymatic biosensors. They serve as highly selective transducing layers for the detection of hydrogen peroxide produced in the course of oxidase-catalyzed reactions. Their effectiveness and reliability in this role have been extensively reported in the field of (bio)analytical chemistry. In this communication, we demonstrate that enzymatically modified PB films can serve not only as efficient biosensing layers but also as effective anti-interference components (scavenger layer) in biosensor architectures. This dual functionality is particularly advantageous in polyenzymatic biosensors, where suppressing signals from interfering intermediate species is essential to ensure high selectivity and analytical accuracy. To demonstrate this dual role of PB, a model bienzymatic biosensor enabling selective sucrose determination while simultaneously suppressing interferences from glucose is presented. This concept, which has not been previously reported in the scientific literature, is demonstrated here using a simple paper-based microfluidic optical biodevice for the simultaneous determination of both sugars without the use of analytical instruments.