Wireless Sensor-Integrated Platform for Localized Dissolved Oxygen Sensing in Bioreactors

This work presents a miniaturized electrochemical sensor-integrated bioprocess monitoring pod (bPod) that wirelessly monitors local dissolved oxygen (DO) saturation within bioreactors in real-time. The system comprises a compact printed circuit board (PCB) that integrates a potentiostat analog-front-end (AFE) and a Bluetooth Low Energy (BLE) microcontroller with an electrochemical DO sensor. In situ detection of DO within the bioreactor is enabled via a 3-D printed ABS-M30i shell, representing a robust and biocompatible packaging solution for prolonged monitoring. The platform is evaluated in a bench-scale bioreactor filled with aqueous media, and data is extracted wirelessly via a custom-developed application. A linear response corresponding to DO saturation levels was achieved using chronoamperometry (CA), exhibiting a dynamic voltage range between 1.3 V ( $-4.9\,\,\mu \text{A}$ ) and 0.87 V ( $-11.1\,\,\mu \text{A}$ ), corresponding to 0% and 100% DO saturation respectively, with a sensitivity of 6.3 mV/DO%. This work highlights a unique sensor assembly and packaging approach to overcome challenges for localized bioprocess monitoring platforms in bioreactors. [2020-0149]