Cell arrays are of foremost importance for many applications in pharmaceutical research or fundamental biology. Although arraying techniques have been widely investigated for adherent cells, organization of cells in suspension has been rarely considered. The arraying of non-adherent cells using the diamagnetic repulsive force is presented. A planar arrangement of Jurkat cells is achieved at the microscale above high quality microfabricated permanent magnets with remanent magnetization of J(r)≈ 1 T, in the presence of a paramagnetic contrast agent. The cytotoxicity of three Gd based contrast agents, Gd-DOTA, Gd-BOPTA and Gd-HP-DO3A, is studied. Among them, Gd-HP-DO3A appears to be the most biocompatible toward Jurkat cells. In close agreement with analytical simulations, diamagnetically 'suspended' cells have been successfully arrayed above square and honeycomb-like micromagnet arrays, which act as a "diamagnetophobic" surface. Living cell trapping is achieved in a simple manner using concentrations of Gd-HP-DO3A as low as 1.5 mM.

3D packaging and hybrid heterogeneous integration are currently attracting considerable interest in the literature. In most publications, the power dies and their respective gate drivers are interconnected using flex or PCB layers. Apart from a few exceptions, packaging is mainly based on separate power and driver dies, focusing on improving the performance of individual chips. This paper presents a different approach in which the design of the power and gate driver chips takes the interconnection of the two dies into account. This method is used in order to simplify and optimize packaging and interconnections and to improve the overall performance. The basic idea is to flip chip the integrated gate driver directly onto the power die, resulting in the 3D heterogeneous assembly of a vertical power device and a CMOS integrated gate driver. In order to simplify the implementation of this solution, the gate driver supply, its storage capacitor and the control signal insulation unit are also integrated and interconnected in and on the two silicon dies. Index Terms--power conversion, semiconductor device packaging, hybrid integrated circuit interconnections