US developer of the patent-protected monitor, Polestar Technologies, has given Cellexus a non-exclusive licensing deal to supply the product as part of its CellMaker Lite disposable bioreactor suite. Polestar developed the optical dissolved oxygen and pH monitor using its fluorescent quenching technology, which works by allowing oxygen detection or pH monitoring by integrating a patch inside the disposable bioreactor. This patch contains a fluorescent indicator, which is embedded in a highly permeable polymeric sensing membrane. Oxygen diffuses through this membrane where it quenches the fluorescence of the indicator molecule - the more oxygen that is present, the more the fluorescence is quenched. Cellexus can now include this small and disposable "patch" on the inner surface of its CellexusBag bioreactors and without having to use an invasive probe, users can measure the concentration of dissolved oxygen and the pH of the culture. "By simply pointing probes at the patches, these two key parameters can be measured," said Kevin Auton, CEO and inventor of the CellexusBag technology. "The devices that record and display these data are very small and are simple to use and the dissolved oxygen concentration or the pH can either be read from the display by an operator or can be output to a data tracking system." According to Polestar, another advantage of its fluorescent quenching technology is that it is non-oxygen consuming and is therefore immune to the type of calibration drift arising from fouling seen with traditional electrodes when they are used in bioreactors. "We believe that Polestar Technologies has a unique IP position in the use of their non-invasive monitoring systems for disposable bioreactors and are looking forward to incorporating these products into our current and future disposable systems," said Auton. Disposable bioreactors are ideal for use as sample bags, for mixing and dispensing media and buffers, collecting cell culture end-products and chromotography fractions and also for storage. These systems can reduces the risk of cross-contamination between batches whilst minimising turnaround time, cleaning costs and validations.