Design and fabrication of Si-neuroprobe arrays
01 Dec 2010-pp 796-800
TL;DR: In this paper, the fabrication of silicon microprobes for neural prosthesis is presented, which can be used to reduce tissue trauma during implant implant insertion and thus serve as an enabling platform for manufacture-able process leading to low cost neurodevices.
Abstract: In this work we proposed designs and demonstrated the fabrication of silicon microprobes for neural prosthesis. Silicon probes of various sizes, cross-sectional shapes and involving different probe encapsulation bio-compatible materials such as Polyimide were fabricated. Especially, isotropically etched (for Si) probes find significant application to reduce tissue trauma during implant. Our approach of using fully CMOS compatible silicon wafer processing with 200mm diameter silicon wafers is to subsequently serve as an enabling platform for manufacture-able process leading to low cost neurodevices. Silicon probes thus fabricated were packaged in order to demonstrate the complete product cycle- “Design-to-Packaging”.
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TL;DR: In this article, a microassembly method for low-profile three-dimensional probe arrays for neural prosthesis and neuroscience applications is presented. And the impedance of the assembled probe is also measured and discussed.
Abstract: This paper presents a microassembly method for low-profile three-dimensional probe arrays for neural prosthesis and neuroscience applications. A silicon (Si) lead transfer structure, Si interposer, is employed to form electrical connections between two orthogonal planes—the two dimensional probes and the dummy application-specific integrated circuit (ASIC) chip. In order to hold the probe array and facilitate the alignment of probes during assembly, a Si platform is designed to have through-substrate slots for the insertion of probes and cavities for holding the Si interposers. The electrical interconnections between the probes and the dummy ASIC chip are formed by solder reflow, resulting in greatly improved throughput in the proposed assembly method. Moreover, since the backbone of the probe can be embedded inside the cavity of the Si platform, the profile of the probe array above the cortical surface can be controlled within 750 µm. This low-profile allows the probe array not to touch the skull after it is implanted on the brain. The impedance of the assembled probe is also measured and discussed.
14 citations
01 Dec 2011
TL;DR: In this paper, a low profile probe array system is proposed for minimizing tissue trauma after implantation, where planar neural probes are assembled with a Si platform to form a 3D probe array, which is then connected to the application-specific integrated circuit (ASIC) chip with a flexible polyimide cable by flip-chip bonding to complete the whole integration.
Abstract: In this work, an integration method of low profile probe array system is proposed for minimizing the tissue trauma after implantation. The planar neural probes was assembled with a Si platform to form a 3D probe array, which is then connected to the application-specific integrated circuit (ASIC) chip with a flexible polyimide cable by flip-chip bonding to complete the whole integration. The probe array and flexible polyimide cable have undergone electrical tests to prove to be highly stable and reliable. With the specially designed components, flexible assembly is achieved. The proposed integration method achieved a low profile of the probe array and the requirements for its applications. The impedance of the assembled probe electrode in artificial cerebrospinal fluid (aCSF) is measured to be about 1.1 MΩ at 1kHz.
3 citations
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TL;DR: Techniques for characterizing electrochemical properties relevant to stimulation and recording are described with examples of differences in the in vitro and in vivo response of electrodes.
Abstract: Electrical stimulation of nerve tissue and recording of neural electrical activity are the basis of emerging prostheses and treatments for spinal cord injury, stroke, sensory deficits, and neurological disorders. An understanding of the electrochemical mechanisms underlying the behavior of neural stimulation and recording electrodes is important for the development of chronically implanted devices, particularly those employing large numbers of microelectrodes. For stimulation, materials that support charge injection by capacitive and faradaic mechanisms are available. These include titanium nitride, platinum, and iridium oxide, each with certain advantages and limitations. The use of charge-balanced waveforms and maximum electrochemical potential excursions as criteria for reversible charge injection with these electrode materials are described and critiqued. Techniques for characterizing electrochemical properties relevant to stimulation and recording are described with examples of differences in the in vitro and in vivo response of electrodes.
1,843 citations
"Design and fabrication of Si-neurop..." refers background in this paper
...With the development of microelectromechanical systems (MEMS) technologies, sophisticated microprobes with electrode arrays have been developed and are widely used in neural activity studies, artificial retinas, motor prosthesis, cochlear implants and so on [1-5]....
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TL;DR: This review presents the biological components and time course of the acute and chronic tissue reaction in brain tissue, analyses the brain tissue response of current electrode systems, and comments on the various material science and bioactive strategies undertaken by electrode designers to enhance electrode performance.
1,741 citations
"Design and fabrication of Si-neurop..." refers background in this paper
...In other words, it can be termed as excessive stress-shielding effect meaning that the brain tissue tries to adapt to the excessive stress generated at the brain and probe interface leading towards the strengthening of the brain tissue and thus evolve (adapt to the high stress) as a scar tissue [9,10]....
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TL;DR: Data indicate that device insertion promotes an early response proportional to device size and a sustained response that is independent of device size, geometry, and surface roughness, which may be associated with the amount of damage generated during insertion.
771 citations
"Design and fabrication of Si-neurop..." refers background in this paper
...The key aspects of the reported designs are (i) the tip of the probe being extremely sharp for easy insertion into the tissue (ii) minimal material and maximum strength of the probe (iii) have the less flexural stiffness so as to accommodate micro movements of the brain [6-8]....
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TL;DR: Control of prostheses using cortical signals is based on chronic microelectrode arrays, extraction algorithms, and prosthetic effectors and has the capability of restoring much of the arm movement lost with immobilizing deficits.
Abstract: Control of prostheses using cortical signals is based on three elements: chronic microelectrode arrays, extraction algorithms, and prosthetic effectors. Arrays of microelectrodes are permanently implanted in cerebral cortex. These arrays must record populations of single- and multiunit activity indefinitely. Information containing position and velocity correlates of animate movement needs to be extracted continuously in real time from the recorded activity. Prosthetic arms, the current effectors used in this work, need to have the agility and configuration of natural arms. Demonstrations using closed-loop control show that subjects change their neural activity to improve performance with these devices. Adaptive-learning algorithms that capitalize on these improvements show that this technology has the capability of restoring much of the arm movement lost with immobilizing deficits.
592 citations
"Design and fabrication of Si-neurop..." refers background in this paper
...With the development of microelectromechanical systems (MEMS) technologies, sophisticated microprobes with electrode arrays have been developed and are widely used in neural activity studies, artificial retinas, motor prosthesis, cochlear implants and so on [1-5]....
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28 Jul 2003
TL;DR: This study investigated the use of planar, silicon-substrate microelectrodes for chronic unit recording in the cerebral cortex and provided a performance baseline to support further electrode system development for intracortical neural implant systems for medical applications.
Abstract: This study investigated the use of planar, silicon-substrate microelectrodes for chronic unit recording in the cerebral cortex. The 16-channel microelectrodes consisted of four penetrating shanks with four recording sites on each shank. The chronic electrode assembly included an integrated silicon ribbon cable and percutaneous connector. In a consecutive series of six rats, 5/6 (83%) of the implanted microelectrodes recorded neuronal spike activity for more than six weeks, with four of the implants (66%) remaining functional for more than 28 weeks. In each animal, more than 80% of the electrode sites recorded spike activity over sequential recording sessions during the postoperative time period. These results provide a performance baseline to support further electrode system development for intracortical neural implant systems for medical applications.
403 citations
"Design and fabrication of Si-neurop..." refers background in this paper
...In other words, it can be termed as excessive stress-shielding effect meaning that the brain tissue tries to adapt to the excessive stress generated at the brain and probe interface leading towards the strengthening of the brain tissue and thus evolve (adapt to the high stress) as a scar tissue [9,10]....
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