A microtool for in vitro cell array manipulation

This paper reports on the fabrication of a transparent micro-post array with supporting pillars for in-vitro cell array manipulation. The capability to manipulate and apply mechanical force to an array of cells will enable the engineering of living neural networks having defined connectivity. The micro-tool described in this paper was designed to achieve this goal. Its transparency permits visual access through a light microscope. When the microtool is placed on top of a cell culture, the tips of the posts are 3-5 μm microns above the surface due to the differential height between the posts and the supporting pillars. This small gap prevents the cells from being damaged when the microtool is translated with respect to the cells, while allowing them to touch and adhere to the posts. The micro-tool was tested by using it to apply force to non-arrayed embryonic chick forebrain cells in vitro. The array was moved at a constant speed of 36 μm/hour during one hour. In response, several neurite-like cytoplasmic processes initiated from cells that had formed adhesions to posts, and these processes elongated in response to further translation. This is the first reported microarray designed to apply mechanical forces to cells.