The REACH-project is a direct result of the FP7 StemExpand project, which aimed at the expansion and engraftment of hematopoietic and mesenchymal stem cells (MSC) for clinical use. The results of these research activities show that a novel, closed and controlled bioreactor can be developed to grow clinically relevant numbers (>400 million) of MSCs. XPand Biotechnology BV(NL) [bioreactor development, technology valorization], Aber Instruments ltd (UK)[biomass sensor] and PreSens Precision Sensing GmbH (GE) [DO, pH sensor] are three SMEs that have teamed up to develop this novel bioreactor system to a pre-commercial scale. The overall aim of the REACH project is to further develop and engineer the bioreactor (incl. valorization, testing and technical and biological validation) to a closed-system sensor-controlled bioreactor with sampling possibilities that allows for GMP-grade MSC production outside a cleanroom. The system will contain a disposable bioreactor bag with unique miniaturized disposable sensors. The DO and pH sensors use optical chemical methods capable of high frequency sampling, this ensures an enhanced stability of the expansion process. Using an expandable bioreactor the volume can be increased during cell culture, without the need for passaging of the cells. Because of this feature the system can be truly closed, without the limitations of a fixed culture substrate area. Leiden University Medical Center (NL) will validate the system and the products in a clinical setting by comparing bioreactor-expanded MSCs with GMP grade MSCs produced by established protocols in the LUMC. Successful development of this bioreactor system will be beneficial for the participating SMEs as well as the medical sector which will be able to develop cell therapies in a faster, cheaper and more efficient way. Collectively, the partners in REACH will develop an exploitation and business plan for the successful valorization of the research done in the FP7 StemExpand project.