Memsensors with a Crossbar Structure for In-vivo H2O2 Detection

Abstract

A molybdenum disulfide $(\mathbf{MoS}_{2})$ based hydrogen peroxide $(\mathbf{H}_{\boldsymbol{2}}\mathbf{O}_{\boldsymbol{2}})$ memsensor (a memory sensor or a sensor with memory) is designed as a passive one oriented to be carried by microrobots, where a local power supply is hardly be available. The sensor has a crossbar configuration and is microfabricated of $\mathbf{Au}/\mathbf{MoS}_{\boldsymbol{2}}/\mathbf{Au}$ with a junction area of 0.25 $\boldsymbol{\mu} \mathbf{m}^{\boldsymbol{2}}$. It functions with physical absorption of oxide ions on the surfaces or between layers and/or chemical oxidation on the edges and defects of $\mathbf{MoS}_{\boldsymbol{2}}$. Due to its nature of irreversible structure, calibration has been done at a lower concentration of $\mathbf{H}_{\boldsymbol{2}}\mathbf{O}_{\boldsymbol{2}}$ and confirmed at a higher one presetting a scenario that the sensor will be carried out by a microrobot being sent to a certain region for sensing $\mathbf{H}_{\boldsymbol{2}}\mathbf{O}_{\boldsymbol{2}}$ with an intermediate concentration and collected back for understanding the information where the microrobot has been staying. Experiments show that the proposed calibration and sensing method has an acceptable resolution in the range of 200 nmol/L to 1200 nmol/L.