Fabrication of 3D Magnetically Driven Soft Microactuator

In this paper we describe a novel fabrication method of three dimensional polymeric magnetically driven microtools (MMT) for non-intrusive and no contamination experiments on a chip. In order to obtain precise and complicated three dimensional patterns of magnetically driven 3D microtools, a grayscale photolithography technique has been applied by making good use of thick nega-photoresist as sacrificed mold. By controlling an amount of ultraviolet light with a gradation of gray tone mask, we have fabricated smoothly curved (gap of approximate to 100 mu m) object without steps which tend to be appeared in case of conventional layer by layer photolithography techniques. A wide range of on-chip application of microactuators can be proposed by using a softness of polymer-based 3D MMT (Young's modulus approximate to 5 MPa). For example, microloader was successfully actuated by the combination of magnetic and fluidic force. This technique has a great impact on automation of cloning process or a single cell diagnostics on a chip with a combination of MMT with other functions of stirrer, valve, sorter and so on.