In late 2017, T-cell therapy became the first gene therapy to have been approved by the US FDA and in 2018 approved for use in the UK. From the clinical data presented thus far, it appears these genetically modified T-cells (a specific type of white blood cell) present a CURE for some of the most aggressive forms of cancer (particularly acute Leukaemia in children). The current manufacture of T-cells is undertaken in a laboratory and can take up to 21 days, depending on the quality of the patient's starting cellular material. The long, complex and expensive process poses the risk of contamination and further complications due to patient variations. Here we propose experiments as part of a larger EPSRC-funded project to move this manufacturing process onto the body. Specifically, we will study a new approach to capture T-cells from whole blood embedded in a microfluidic device under flow.