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This paper discusses the modelling, design and characterization of planar micr~xoils to be used in telemetu' systems that supply energy to miniaturized implants. Parasitic electrical effects that may become important at a.c. frequencies of se',eral megahertz are e,,aluated. The fabrication process and electrical characterization of planar recei,,er microcoils ~vill be described, and it will be ,,hown that a power of a few milliwatts is feasible. Co) 1997 Elsevier Science S.A.

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Abstract-Anovel electrochemical microactuator was developed, which operates as an active valve. The microactuator consists of an electrochemical cell and a membrane that deflects because of the pressure of oxygen gas generated by electrolysis. Relatively large pressures (up to tens of bars) can be reached with only low energy consumption (in the PW range). In a first prototype a Cu/aq. 1 M CuSOdPt system was used in an electrochemical cell with dimensions 2 x 2 x 1 mm3, fabricated with silicon micromachining and thin film deposition techniques. When the actuator was driven at 1.6 V and currents below 50 pA, pressures of 2 bar could be obtained within seconds, causing membrane deflections in the 30 to 70 pm range. It was found that, in order to improve the performance of the microactuator, it will be necessary to replace the Cu/Cu2 + electrode. A possible alternative is the Sb/Sb-oxide electrode. This system was studied by cyclic voltammetry and the first results are promising. 0 1997 Published by Elsevier Science Ltd

In this study we investigated the applicability of the (silver-enhanced) immunogold labeling method for atomic force microscopy. Human lymphocytes were labeled with anti-CD3 conjugated to fluorescein isothiocyanate and a secondary antibody (goat anti-mouse) linked with 1- or 30-nm colloidal gold particles. Silver enhancement was applied on these labeled cells to increase the size of the labels. In a setup combining an inverted optical microscope and a stand-alone atomic force microscope, a direct correlation was made between the force and the fluorescent images. Additionally, we performed flow cytometric analysis. From the results we conclude that immunogold labeling using small labels (1 nm) in combination with silver enhancement (30 min) proves to be a reliable method for high-resolution cell surface antigen detection in atomic force microscopy.