All Publications

  • Enhanced Thin-Film Encapsulation Through Micron-Scale Anchors ADVANCED FUNCTIONAL MATERIALS Hemed, N., Pham, A., Zhao, E. T., Wang, P., Melosh, N. A. 2024
  • A 1024-Channel 268-nW/Pixel 36 x 36 μm<SUP>2</SUP>/Channel Data-Compressive Neural Recording IC for High-Bandwidth Brain-Computer Interfaces IEEE JOURNAL OF SOLID-STATE CIRCUITS Jang, M., Hays, M., Yu, W., Lee, C., Caragiulo, P., Ramkaj, A. T., Wang, P., Phillips, A. J., Vitale, N., Tandon, P., Yan, P., Mak, P., Chae, Y., Chichilnisky, E. J., Murmann, B., Muratore, D. G. 2023
  • A CMOS-based highly scalable flexible neural electrode interface. Science advances Zhao, E. T., Hull, J. M., Mintz Hemed, N., Uluşan, H., Bartram, J., Zhang, A., Wang, P., Pham, A., Ronchi, S., Huguenard, J. R., Hierlemann, A., Melosh, N. A. 2023; 9 (23): eadf9524


    Perception, thoughts, and actions are encoded by the coordinated activity of large neuronal populations spread over large areas. However, existing electrophysiological devices are limited by their scalability in capturing this cortex-wide activity. Here, we developed an electrode connector based on an ultra-conformable thin-film electrode array that self-assembles onto silicon microelectrode arrays enabling multithousand channel counts at a millimeter scale. The interconnects are formed using microfabricated electrode pads suspended by thin support arms, termed Flex2Chip. Capillary-assisted assembly drives the pads to deform toward the chip surface, and van der Waals forces maintain this deformation, establishing Ohmic contact. Flex2Chip arrays successfully measured extracellular action potentials ex vivo and resolved micrometer scale seizure propagation trajectories in epileptic mice. We find that seizure dynamics in absence epilepsy in the Scn8a+/- model do not have constant propagation trajectories.

    View details for DOI 10.1126/sciadv.adf9524

    View details for PubMedID 37285436

    View details for PubMedCentralID PMC10246892

  • Direct-print three-dimensional electrodes for large- scale, high-density, and customizable neural inter- faces. bioRxiv : the preprint server for biology Wang, P., Wu, E. G., Uluşan, H., Phillips, A. J., Rose Hays, M., Kling, A., Zhao, E. T., Madugula, S., Vilkhu, R. S., Vasireddy, P. K., Hier-Lemann, A., Hong, G., Chichilnisky, E. J., Melosh, N. A. 2023


    Silicon-based planar microelectronics is a powerful tool for scalably recording and modulating neural activity at high spatiotemporal resolution, but it remains challenging to target neural structures in three dimensions (3D). We present a method for directly fabricating 3D arrays of tissue-penetrating microelectrodes onto silicon microelectronics. Leveraging a high-resolution 3D printing technology based on 2-photon polymerization and scalable microfabrication processes, we fabricated arrays of 6,600 microelectrodes 10-130 μm tall and at 35-μm pitch onto a planar silicon-based microelectrode array. The process enables customizable electrode shape, height and positioning for precise targeting of neuron populations distributed in 3D. As a proof of concept, we addressed the challenge of specifically targeting retinal ganglion cell (RGC) somas when interfacing with the retina. The array was customized for insertion into the retina and recording from somas while avoiding the axon layer. We verified locations of the microelectrodes with confocal microscopy and recorded high-resolution spontaneous RGC activity at cellular resolution. This revealed strong somatic and dendritic components with little axon contribution, unlike recordings with planar microelectrode arrays. The technology could be a versatile solution for interfacing silicon microelectronics with neural structures and modulating neural activity at large scale with single-cell resolution.

    View details for DOI 10.1101/2023.05.30.542925

    View details for PubMedID 37398164

    View details for PubMedCentralID PMC10312573

  • Automated and Wireless Accelerated Heat Soak Testing System to Assess Hermetic Failure Mechanism of Inductively Powered Implantable Medical Applications ADVANCED MATERIALS TECHNOLOGIES Yeon, P., Kim, M., Wang, P., Kim, C., Brand, O., Ghovanloo, M. 2023
  • A scalable bonding technique for the development of next-generation brain-machine interfaces Wang, P., Goh, T., Hemed, N., Melosh, N., IEEE IEEE. 2019: 863–66
  • Direct microfabrication of oxide patterns by local electrodeposition of precisely positioned electrolyte: the case of Cu2O SCIENTIFIC REPORTS Wang, P., Roberts, R. C., Ngan, A. W. 2016; 6: 27423


    An efficient technique for writing 2D oxide patterns on conductive substrates is proposed and demonstrated in this paper. The technique concerns a novel concept for selective electrodeposition, in which a minimum quantity of liquid electrolyte, through an extrusion nozzle, is delivered and manipulated into the desired shape on the substrate, meanwhile being electrodeposited into the product by an applied voltage across the nozzle and substrate. Patterns of primarily Cu2O with 80~90% molar fraction are successfully fabricated on stainless steel substrates using this method. A key factor that allows the solid product to be primarily oxide Cu2O instead of metal Cu - the product predicted by the equilibrium Pourbaix diagram given the unusually large absolute deposition voltage used in this method, is the non-equilibrium condition involved in the process due to the short deposition time. Other factors including the motion of the extrusion nozzle relative to the substrate and the surface profile of the substrate that influence the electrodeposition performance are also discussed.

    View details for DOI 10.1038/srep27423

    View details for Web of Science ID 000377011300001

    View details for PubMedID 27255188

    View details for PubMedCentralID PMC4891777