Self-assemblying of tissue spheroids on polymeric membranes

In this study multicellular tissue spheroids were fabricated on polymeric membranes in order to accelerate the fusion process and tissue formation. To this purpose tissue spheroids composed of three different cell types, myoblasts, fibroblasts and neural cells were formed and cultured on agarose and membranes of polycaprolactone (PCL) and chitosan (CHT). Membranes prepared by phase inversion technique display different physico-chemical, mechanical and transport properties, which can affect the fusion process. Membranes accelerated the fusion process of a pair of spheroids with respect to the inert substrate. In this process a critical role is played by the membrane properties especially by mechanical characteristics and the oxygen and carbon dioxide mass transfer. The rate of fusion was quantified and found to be similar for fibroblast, myoblast and neural tissue spheroids on membranes, which completed the fusion within 3 days. These spheroids underwent a faster fusion and maturation on PCL membrane in comparison with agarose, the rate of fusion being proportional to the value of oxygen and carbon dioxide permeances and elastic characteristics. Consequently, tissue spheroids on the membranes expressed high biological activity in terms of oxygen uptake making them more suitable as building blocks in the fabrication of tissues and organs.