Wrinkle-free bonding of thin membranes in a microfluidic bioreactor

Understanding the interaction between plants and pathogens, like fungi, allows to develop a more sustainable plant protection. A better knowledge of the communication between a host plant and the attacking fungi could allow to boost the systemic resistance of this crop. A microfluid bioreactor (MBR) allows to share the same supply flow for the cultivation of fungi and plant cells but to keep them spatially apart, to be able to analyse the signalling molecules be-tween them. Such MBRs exist and are in use, however, it has been noticed that the current assembly process for the MBR – ultrasonic welding – leads to the development of strong wrinkles in the membrane dividing the cultivation chamber from the supply chamber. This hampers the even flow conditions and creates uneven cultivation areas. Thus, a less aggressive assembly process – laser transmission welding (LTW) – was tested for the installation of the mem-brane in the MBR and sealing the chip halves tight. The results were promising as LTW created less wrinkles. However, the seal of the laser transmission welded MBR was not as strong as an ultrasonically welded one. Based on these find-ings we derived a new design that should evade the current problems.