Electrochemical Dissolved Oxygen Sensor-Integrated Platform for Wireless In Situ Bioprocess Monitoring

•Integrated wireless platform for real-time, autonomous, in situ electrochemical monitoring of chemical analytes in bioreactors.•Dissolved oxygen is electrochemically detected by a tape-based Clark-type sensor•Entire free-floating system is implemented in a 3-D printed shell including the sensor, supporting electronics, a battery and a Bluetooth Low Energy wireless link for data transmission.•Potential applications in bioprocess monitoring in large-scale industrial bioreactors. This work presents a bio-processing online device (bPod) platform, capable of real-time in situ monitoring of bioreactor cell culture parameters, such as dissolved oxygen (DO). The bPod is an integrated system comprised of a potentiostat analog-front-end (AFE), a Bluetooth Low Energy (BLE) microcontroller, and a chemical sensor, exemplified here by a Clark-type DO sensor, which enables monitoring of dissolved oxygen content. The Clark-type electrochemical sensor performs chronoamperometric measurement of DO percent saturation, and the BLE microcontroller wirelessly transmits data to a smartphone while submerged in aqueous media. After several electrode design modifications, the bPod showed a linear electrochemical current response corresponding to DO percent saturation levels with a sensitivity of 37.5 nA/DO% and limit of detection of 8.26 DO%, covering concentration ranges relevant for mammalian culture processes within bioreactors. The wireless bPod provides a free-floating capsule architecture for monitoring DO and can be adapted for an array of electrochemical sensors, targeting different process parameters for diverse bioprocess monitoring applications.