A TiNi/diamond-like-carbon (DLC) microcage has been designed for biological applications. The structure is composed of a top layer of TiNi film and a bottom layer of highly compressively stressed DLC for upward bending once released from the substrate. The fingers of the microcage quickly close through the shape memory effect once the temperature reaches the austenite start transformation point to execute the gripping action. Opening the microcage is realized by either decreasing the temperature to make use of the martensitic transformation or further increasing the temperature to use the bimorph thermal effect. The biocompatibility of both the TiNi and DLC films has been investigated using a cell-culture method. © 2008 IOP Publishing Ltd.