Establishing a method to transport and deliver adipose derived stem cells to chronic wounds

Chronic wounds present a challenge to heal due to the surrounding complications they often present with. These wounds are both debilitating and distressing to patients and can lead to amputation of the afflicted limb. Stem cell therapy is currently being investigated as a method of healing these wounds, however delivery and transport methods of stem cells are not universally agreed on. The aim of this thesis was to present a method of delivering adipose derived stem cells to a human skin model, keeping cells viable whilst out of conventional culture conditions in a ‘ready to use’ product requiring no further processing at point of use. Specific objectives were to assess which biomaterials readily supported cells over a period of 3 days. In this investigation human derived keratinocytes, fibroblasts, adipose derived stem cells and bone marrow derived stem cells were seeded onto synthetic poly(lactic-co-glycolic acid) or encapsulated in fibrin gels and cell viability assessed using an MTT assay. These cell and scaffold combinations were further assessed when in transport conditions, left in ambient conditions (~22°C) with or without supplementing airtight containers with 5% CO2 to aid the carbonate buffering of the cell media, compared to controls at 37°C in a conventional incubator with 5% CO2 supplementation. It was found that maintaining pH by use of 5% CO2 supplementation was a requirement for keeping these cell types viable over 3 days. Finally, characteristics of adipose derived stem cells were investigated when encapsulated in fibrin gels after being in transport conditions for 48 hours by their ability to differentiate, ability to migrate to a skin wound mode and retention of common stem cell markers. In summary, human cells can be supported and maintained when outside of conventional culture conditions providing that pH of cell media is maintained by supplementing air with 5% CO2. Furthermore, adipose derived stem cells encapsulated in fibrin gels can be transported in these conditions whilst retaining common stem cell markers.