A single link to the first track to allow the export script to build the search page
  • Addiction, Drugs
  • Information from Lay-Language Summaries is Embargoed Until the Conclusion of the Scientific Presentation

    218—Nanotools for Neuroscience

    Sunday, November 10, 2013, 1:00 pm - 3:45 pm

    218.03: Three-dimensional macroporous nanowire nanoelectronic network for brain implant

    Location: 7B

    *C. XIE, J. LIU, X. DAI, W. ZHOU, C. M. LIEBER;
    Harvard Univ., Cambridge, MA

    Abstract Body: Long-term and stable brain machine interface requires a seamless integration of the brain implant and the brain tissue. Micro-fabricated brain implants have been widely used in both basic neuroscience and clinical neural prosthetics. However, the resultant tissue response to the presence of the implant has been the greatest challenge facing their long-term functioning. After implantation, chronic deterioration of the implant-tissue interface is elicited by the huge physical property mismatch between the implants and the brain tissue. For instance, brain implants, usually made from metal or silicon, have an elastic modulus 107 times larger than that of the brain tissue.
    Nanowire based macroporous nanoelectronic networks, recently developed in our group, have been demonstrated to have (i) extremely low bending stiffness which is similar to that of brain tissue, (ii) three-dimensional (3D) macroporous structure that allows the implant and tissue interpenetrate into each other, (iii) microscale-to-nanoscale feature sizes and nanoscale feature units.
    In this work, we demonstrate the design and implantation of the 3D macroporous nanoelectronic neural probe, and show their potential as a seamless brain machine interface. The 3D macroporous nanoelectronic neural probes are constructed by semiconducting silicon nanowires (30 nm in diameter and 2 um in channel length) as sensing units, metal contacts (100 nm in thickness, 5 um in width), and two polymer encapsulation layers (300 nm in thickness, 7 um in width). The probes are free-standing in solutions with an ultra-low effective bending stiffness of 0.04 nN/m. We further assign different build-in strains at different region of the probes to fine control the global structure and the local gesture of the probes. In consequence, we are able to optimize the probe-tissue interface and their integration after implantation. 3D macroporous nanoelectronic neural probes are extremely soft. In order to meet the mechanical requirement during the implantation, we introduce a strategy to temporarily increase the probe strength using a low temperature treatment in liquid nitrogen. With that, we successfully implanted these probes into rat brains with minimum surgery damage. Multiplexed local field potential recordings from the motor cortex and somatosensory areas are demonstrated. In addition, histology analysis and long-term stability of the probe-tissue interface will also be described.
    J. Liu, C. Xie, X. Dai, L. Jin, W. Zhou and C.M. Lieber, Proc. Natl. Acad. Sci. USA 110, 6694-6699 (2013).
    B. Tian, J. Liu, T. Dvir, L. Jin, J.H. Tsui, Q. Qing, Z. Suo, R. Langer, D.S. Kohane and C.M. Lieber, Nature Mater. 11, 986-994 (2012)

    Lay Language Summary: Three-dimensional Macroporous Nanowire Nanoelectronic Networks for Brain Probes
    In this work, we designed, fabricated and implemented a novel type of brain probe, macroporous nanoelectronic neural probe, which allows for a “seamless” implant-tissue interface.
    Long-term and stable brain machine interface requires a seamless integration of the brain implant and the brain tissue. Micro-fabricated brain implants have been widely used in both basic neuroscience and clinical neural prosthetics. However, the resultant tissue response to the presence of the implant has been the greatest challenge facing their long-term functioning. After implantation, chronic deterioration of the implant-tissue interface is elicited by the huge physical property mismatch between the implants and the brain tissue. For instance, brain implants, usually made from metal or silicon, have an elastic modulus 107 times larger than that of the brain tissue.
    Semiconducting nanowire based macroporous nanoelectronic networks, recently developed in our group, can overcome these limitations since they have (i) extremely low bending stiffness (highly flexible) similar to that of brain tissue, (ii) three-dimensional (3D) macroporous structure that allows interpenetration of the implant and tissue, (iii) only biologically-relevant microscale-to-nanoscale feature sizes, and (iv) inert and bio-compatible properties.
    Here, we demonstrate the design, fabrication and implantation of a novel 3D macroporous nanoelectronic neural probe. These probes are highly flexible and free-standing in solution. They are designed with built-in strains to control both global and local device structures, which allow the probe-tissue interface to be optimized. In order to meet the mechanical requirement during the implantation, the soft 3D macroporous nanoelectronic neural probes were inserted in a ‘frozen’ state into the brains of anesthetized rats with minimal surgical damage. Multiplexed recordings from both the motor cortex and somatosensory areas have been demonstrated. In addition, histology analysis reveals the long-term stability of the probe-tissue interface.
    These novel probes could lead to opportunities for brain activity mapping and as chronic implants for next generation brain-machine interfaces.