Polyhedral oligomeric silsequioxane-polyurethane nanocomposite microvessels for an artificial capillary bed.

Fabricating artificial vascularised tissue would involve tissue-engineering techniques, but current technology limits this as cultured cells depend on growth media in vitro and on diffusion in vivo. Therefore, there is a need to construct a synthetic microvascular network, which would sustain these cultured cells in a similar manner to normal tissue. This is again hampered by the poor patency rates of current microvascular grafts. Based on our previous work on polyhedral oligomeric silsesquioxane-polyurethane nanocomposites, which have shown the unique ability to repel coagulant proteins whilst still allowing endothelialisation, we have now developed a new generation of microvascular prosthesis using this polymer. Using these dip-coated nanocomposite microvessels, we have shown that it is possible to mimic the hydraulic conductivity and pressure-responsive radial compliance characteristics of biological microvessels. This would allow nutrient exchange across its walls as well as minimise compliance mismatch throughout the physiological pressure range thus reducing intimal hyperplasia in the long term. This microvessel would have the following implications: (1) as a microvascular substitute to vein grafts and (2) in the future as a component of a microvascular network.