Sensors for disposable bioreactors

Modern bioprocess monitoring demands sensors that provide on‐line information about the process state. In particular, sensors for monitoring bioprocesses carried out in single‐use bioreactors are needed because disposable systems are becoming increasingly important for biotechnological applications. Requirements for the sensors used in these single‐use bioreactors are different than those used in classical reusable bioreactors. For example, long lifetime or resistance to steam and cleaning procedures are less crucial factors, while a requirement of sensors for disposable bioreactors is a cost that is reasonable on a per‐use basis. Here, we present an overview of current and emerging sensors for single‐use bioreactors, organized by the type of interface of the sensor systems to the bioreactor. A major focus is on non‐invasive, in‐situ sensors that are based on electromagnetic, semiconducting, optical, or ultrasonic measurements. In addition, new technologies like radio‐frequency identification sensors or free‐floating sensor spheres are presented. Notably, at this time there is no standard interface between single‐use bioreactors and the sensors discussed here. In the future, manufacturers should address this shortcoming to promote single‐use bioprocess monitoring and control.