Surface-modified silicon nano-channel for urea sensing

Silicon nano-channels have been surface functionalized with the enzyme urease for biosensor applications to detect and quantify urea concentration. The device is nanofabricated from a silicon-on-insulator (SOI) wafer with a top down lithography approach. The differential conductance of silicon nano-channels can be tuned for optimum performance using the source drain bias voltage, and is sensitive to urea at low concentration. The experimental results show a linear relationship between surface potential change and urea concentration in the range of 0.1–0.68 mM. The sensitivity of our devices shows high reproducibility with time and different measurement conditions. The nano-channel urea biosensor offers the possibility of high quality, reusable enzyme sensor array integration with silicon-based circuits.