A low-cost, flexible electrochemical sensor for monitoring silver ion concentration in alginate wound dressings

We present an inexpensive flexible Ag⁺ sensor on a paper substrate that can be embedded into commercial silver dressings to enable real-time monitoring of the Ag⁺ concentration in situ. The sensor consists of a silver measuring electrode and a Ag/AgCl reference electrode screen-printed on a laser-machined parchment paper substrate; the reference electrode is covered with PDMS chambers of KCl and KNO₃ to form a double-junction electrode. The fabrication features layerby-layer assembly with no need for expensive cleanroom processes. Experiments in aqueous solutions of various concentrations of AgNO₃ show a generated potential that is linear (r²=0.9752) with log[Ag⁺] and has a sensitivity of 62 mV/decade.