Electrical activation of central and peripheral nervous system has been investigated for treatment of neural disorders for many decades and a number of devices have already moved into clinical phase with success. As we learn more about the neural circuitry in the spinal cord and the brain, new applications are targeting more specific circuits in the central nervous system and thus requiring much more localized means of electrical stimulation. Some example neural prosthetic applications are microstimulation of the spinal cord to restore locomotion or micturition in spinal cord injury, microstimulation of the cochlear nucleus, midbrain, or auditory cortex to restore hearing, and stimulation of the visual cortex in the blind subjects. In order to satisfy the demand in these applications, microelectrode arrays have been developed over the past decade. However, the current implantable microelectrode arrays use wired interconnects for applying the electric stimulations. These fine wires are a major source of device failure since they are the first to break in chronic implants. Moreover, the brain and the spinal cord experience significant amounts of translation inside the skull and the spinal column. Movement of the tissue around these rigid microelectrodes causes significant shear forces due to the mechanical mismatch between the electrode material and the neural tissue. These shear forces, exacerbated by the tethering forces of the wired interconnects, result in a thick encapsulation tissue layer that forms around the electrode. The mechanical mismatch and tethering forces not only cause cellular damage but also the loss of specificity of the stimulations because of this barrier that forms between the electrode and the targeted neurons. We propose a floating micro-electrical device as an alternative technology to micro-electrode arrays. The proposed micro-stimulators will be energized with an infrared light beam through an optical fiber located just outside the dura mater. The floating microstimulators will be free from any interconnects and tethering forces. Because the overall device size is much smaller, the insult to the neural tissue will also be much reduced. The main objective of this proposal is to develop and characterize these floating light activated micro-electrical stimulators (FLAMES). This technology can be instrumental in translation of many neural prosthetic approaches into the clinic, particularly those that involve microstimulation of the spinal cord.

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The main objective of this proposal is to develop and test wireless microstimulators (<300 micron) for electrical activation of the central nervous system in neural prosthetic applications, such as those developed for individuals with spinal cord injury to regain some vital functions. We believe that these wireless micro-stimulators will eliminate the problems encountered with current microelectrode technology and thus enable the transfer of many neural prosthetic projects into the clinic.

National Institute of Health (NIH)
National Institute of Biomedical Imaging and Bioengineering (NIBIB)
Research Project (R01)
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Neurotechnology Study Section (NT)
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Peng, Grace
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Rutgers University
Biomedical Engineering
Schools of Engineering
United States
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Ersen, Ali; Sahin, Mesut (2017) Polydimethylsiloxane-based optical waveguides for tetherless powering of floating microstimulators. J Biomed Opt 22:55005
Ersen, Ali; Elkabes, Stella; Freedman, David S et al. (2015) Chronic tissue response to untethered microelectrode implants in the rat brain and spinal cord. J Neural Eng 12:016019
Ersen, Ali; Abdo, Ammar; Sahin, Mesut (2014) Temperature elevation profile inside the rat brain induced by a laser beam. J Biomed Opt 19:15009
Kuzma-Kuzniarska, Maria; Yapp, Clarence; Pearson-Jones, Thomas W et al. (2014) Functional assessment of gap junctions in monolayer and three-dimensional cultures of human tendon cells using fluorescence recovery after photobleaching. J Biomed Opt 19:15001
Seymour, Elif Ç; Freedman, David S; Gökkavas, Mutlu et al. (2014) Improved selectivity from a wavelength addressable device for wireless stimulation of neural tissue. Front Neuroeng 7:5
Abdo, Ammar; Ersen, Ali; Sahin, Mesut (2013) Near-infrared light penetration profile in the rodent brain. J Biomed Opt 18:075001
Abdo, Ammar; Ersen, Ali; Sahin, Mesut (2011) Temperature elevation inside neural tissue illuminated by NIR laser. Conf Proc IEEE Eng Med Biol Soc 2011:3987-9
Abdo, Ammar; Sahin, Mesut; Freedman, David S et al. (2011) Floating light-activated microelectrical stimulators tested in the rat spinal cord. J Neural Eng 8:056012
Sahin, Mesut; Pikov, Victor (2011) Wireless microstimulators for neural prosthetics. Crit Rev Biomed Eng 39:63-77
Abdo, Ammar; Sahin, Mesut (2011) Feasibility of Neural Stimulation With Floating-Light-Activated Microelectrical Stimulators. IEEE Trans Biomed Circuits Syst 2011:1

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