Series of time-lapse images of microtentacles on the surface of a breast tumor cell (confocal image taken every 10 seconds). Cells are held by lipid tethers to the surface of microfluidic channels, to allow confocal microscopy of microtentacle dynamics without the blurring aided by drift of floating tumor cells. Since the microenvironments of metastasis (blood circulation, lymphatic) discover the transit of tumor cells in a floating state, this cell-linking technology allows studying the dynamics of floating cells to improve the understanding of metastasis.