Traditional electrochemical biosensors have long used reference electrodes to ensure measurement stability. However, the use of such reference electrodes, often made of materials such as silver, pose challenges when creating low-cost, disposable devices. To address this issue, Léonard Bezinge in collaboration with the Shih Group have been exploring two-electrode detection systems that eliminate the need for a reference electrode altogether. The approach simplifies and reduces fabrication costs by forming graphitised electrodes within nitrocellulose paper via laser-pyrolysis. Importantly, readout is performed by a $3 in-house made reader, enhancing the utility and accessibility of the platform. The team applied their platform to detect urinary creatinine, a crucial diagnostic marker for kidney function. Specifically, the system uses a ferricyanide-mediated (Fe(CN)63-) electrochemical reaction, an until now obscure system in the electrochemical sensing field, with the system demonstrating comparable performance to gold-standard commercial laboratory assays. This work not only defines an exciting new platform for point-of-care diagnostics, but also provides unprecedented insights into the ferricyanide-mediated reaction itself.
Written by Javier Hernández
Read the published article here.