Three-dimensional tissue model in direct contact with an on-chip vascular bed enabled by removable membranes

Three-dimensional (3D) tissue culture is a powerful tool for understanding physiological events. However, 3D tissues still have limitations in their size, culture period, and maturity, which are caused by the lack of nutrients and oxygen supply through the vasculature. Here, we propose a new method for culturing a 3D tissue-a spheroid-directly on an 'on-chip vascular bed'. The method can be applied to any 3D tissue because the vascular bed is preformed, so that angiogenic factors from the tissue are not necessary to induce vasculature. The essential component of the assay system is the removable membrane that initially separates the 3D tissue culture well and the microchannel in which a uniform vascular bed is formed, and then allows the tissue to be settled directly onto the vascular bed following its removal. This in vitro system offers a new technique for evaluating the effects of vasculature on 3D tissues.