A platform to restore intra-tissue flow in live explant assays

Tissue resection during first-line surgery is a standard strategy in the clinic for several life-threatening diseases, such as cancer. In case of malignancy, despite the benefits from surgery, cancer often becomes treatment-resistant and metastasises, limiting therapeutic options and patient survival. Due to tumour heterogeneity, treatment personalisation can improve patient outcomes, however tools based on native tissue samples, used for patient-specific drug screening remain very limited. This is primarily due to the diffusion-limited mass transport in static culture conditions, where tissue viability is rapidly reduced due to ischemia. Our aim is to develop a platform that restores intra-tissue flow through native tissue specimens to prolong their preservation ex vivo. Flow of culture media around tissue specimens has been commonly used for sample preservation. However, the efficacy of most currently available platforms has been limited, as ex vivo specimen perfusion is not facilitated in these technologies. As fluid is allowed to travel around specimen periphery, intra-tissue flow is hydraulically disadvantaged and benefits from culture media renewal only affect cells within 200 μm from explant surface. In this thesis, a novel system is presented that comprises a channel-based device with a suitably-designed constriction to block peri-fusion (i.e. flow around the tissue) and facilitate specimen entrapment and perfusion. Using a syringe pump, device efficacy to facilitate intra-tissue flow was investigated, showing that the induced perfusion occurred through both the vasculature and the interstitium. The effects of perfusion on specimen maintenance and function were also investigated. It was showed that healthy mouse liver and cancerous mouse and human omental specimens were better preserved under perfused conditions in the developed apparatus for 48h. Intra-tissue flow was also effective to inhibit cell metabolism after a 2h-specimen perfusion with a metabolic poison, suggesting this system may have great potential for predictive, live explant assays.Open Acces