Due to their shape anisotropy, high aspect ratio magnetic nanoparticles offer many advantages in biomedical applications. For biocompatibility, it is essential to have full control over the dimensions and surface chemistry of the particles. The aim of this study was to synthesize biocompatible nanowires with tuneable dimensions. This was achieved by electrodeposition of Ni in polycarbonate membranes. To ensure biocompatibility, a continuous gold coating was deposited onto the Ni wires by a newly developed electroless deposition method. The coating was analysed using electron microscopy and X-ray diffraction. Magnetic properties, anisotropy and Au film thickness were studied using vibrating sample magnetometry. After biofunctionalization, no significant cytotoxic effects were found in studies involving a diverse range of primary and tumour cells exposed to increasing concentrations of nanowires for up to 7 days. These nanowires may thus be used for in vivo applications such as magnetic drug delivery.

Activation of the T cell receptor (TCR) on the T cell through ligation with antigen-MHC complex of an antigen-presenting cell (APC) is an essential process in the activation of T cells and induction of the subsequent adaptive immune response. Upon activation, the TCR, together with its associated co-receptor CD3 complex, assembles in signaling microclusters that are transported to the center of the organizational structure at the T cell-APC interface termed the immunological synapse (IS). During IS formation, local cell surface receptors and associated intracellular molecules are reorganized, ultimately creating the typical bull's eye-shaped pattern of the IS. CD6 is a surface glycoprotein receptor, which has been previously shown to associate with CD3 and co-localize to the center of the IS in static conditions or stable T cell-APC contacts. In this study, we report the use of different experimental set-ups analyzed with microscopy techniques to study the dynamics and stability of CD6-TCR/CD3 interaction dynamics and stability during IS formation in more detail. We exploited antibody spots, created with microcontact printing, and antibody-coated beads, and could demonstrate that CD6 and the TCR/CD3 complex co-localize and are recruited into a stimulatory cluster on the cell surface of T cells. Furthermore, we demonstrate, for the first time, that CD6 forms microclusters co-localizing with TCR/CD3 microclusters during IS formation on supported lipid bilayers. These co-localizing CD6 and TCR/CD3 microclusters are both radially transported toward the center of the IS formed in T cells, in an actin polymerization-dependent manner. Overall, our findings further substantiate the role of CD6 during IS formation and provide novel insight into the dynamic properties of this CD6-TCR/CD3 complex interplay. From a methodological point of view, the biophysical approaches used to characterize these receptors are complementary and amenable for investigation of the dynamic interactions of other membrane receptors.

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<p>Nitrogen compounds such as nitrogen dioxide (NO<sub>2</sub>) and ammonia (NH<sub>3</sub>) contribute significantly to air pollution and environmental degradation. Fine-grained networks of sensors for ambient nitrogen compounds can be used to inform policy makers and farmers about the effectiveness of techniques to reduce emissions of nitrogen compounds. We are developing a low-cost self-sustaining sensor system that can be deployed outdoors in large numbers in and around agricultural areas to measure the concentration of NH<sub>3</sub>, NO<sub>2</sub>, temperature and humidity with a high spatiotemporal resolution. We use off-the-shelf electrochemical sensors to measure nitrogen compounds. A preliminary comparison between the NH<sub>3</sub> measurements taken by our sensor system and by a differential optical absorption spectroscopy instrument (miniDOAS) demonstrate encouraging results. After calibration, the measurements from our system show fairly good agreement with hourly-averaged miniDOAS measurements, at concentrations down to ~20 µg/m<sup>3</sup>. We are currently setting up a larger validation study to further assess the performance and robustness of our system in different outdoor agricultural environments. Our sensor system has the potential to greatly expand the availability and affordability of NH<sub>3</sub> monitoring across wide areas, enabling farmers and policymakers to gain insights on the effectiveness of potential nitrogen reduction measures.</p>