Open-cell recording of action potentials using active electrode arrays

The investigation of complex communication in cellular networks requires superior measurement tools than those available to date. Electrode arrays integrated onto silicon electronics are increasingly used to measure the electrical activity of cells in an automated and highly parallelized fashion, but they are restricted to recording extracellular potentials. Here, we report on an array of TiN electrodes built using standard silicon electronics for intracellular action potential recording. Intracellular access, possible at each of the 16 384 electrodes on the chip, was accomplished by local membrane electroporation using electrical stimulation with subcellular, micrometer-sized electrodes. Access to the cell interior was transient and could be tuned in duration by adapting the electroporation protocol. Intracellular sensing was found to be minimally invasive in the short and long-term, allowing consecutive intracellular recordings from the same cell over the course of days. Finally, we applied this method to investigate the effect of an ion channel blocker on cardiac electrical activity. This technique opens the door to massively parallel, long-term intracellular recording for fundamental electrophysiology and drug screening.status: publishe

Low loss CMOS-compatible PECVD silicon nitride waveguides and grating couplers for blue light optogenetic applications

© 2009-2012 IEEE. This paper presents silicon nitride (SixNy) photonic integrated circuits (PICs) with high performance at a wavelength of 450 nm, which, therefore, is suitable for neuronal stimulation with optogenetics. These PICs consist of straight and bent waveguides, and grating couplers that are fabricated in a complementary metal-oxide-semiconductor (CMOS)-compatible plasma enhanced chemical vapor deposition SixNy platform. Their characterization shows propagation losses of 0.96 $\pm$ 0.4 dB/cm on average for straight waveguides that are 1-5 $\mu$m wide and bend insertion losses as low as 0.2 dB/90 $^\circ$ for 1 $\mu$m wide waveguides with a radius of 100 $\mu$m. Additionally, the grating coupler characterization shows that they can deliver about 10 $\mu$W of light in an area of 5 $\times$ 9 $\mu$m2 (240 mW/mm2), which is captured from an uncollimated laser diode (70 mW). Besides delivering sufficient power for optogenetic applications, the gratings have dimensions that are comparable to the size of a neuron, which would allow single cell interaction. These results demonstrate that, with this SixNy platform, high-density and large-scale implantable neural devices can be fabricated and readily integrated into existing CMOS-compatible neuro-electronic platforms.status: publishe

Alirocumab and cardiovascular outcomes after acute coronary syndrome

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Alirocumab and Cardiovascular Outcomes after Acute Coronary Syndrome

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