Wireless Microstimulators for Neural Prosthetics

Şahin, Mesut; Pikov, Victor

doi:10.1615/critrevbiomedeng.v39.i1.50

Cited by 23 publications

(17 citation statements)

References 81 publications

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“…Wireless neural stimulators are being developed to avoid complications associated with traditional lead-based implants (Sahin and Pikov, 2011 ). These complications include lead-breakage, scar-tissue growth, MRI restrictions, and undesirable tethering during animal studies (Hamani and Temel, 2012 ; Desai et al, 2015 ; Ersen et al, 2015 ).…”

Section: Introductionmentioning

confidence: 99%

A Sub-millimeter, Inductively Powered Neural Stimulator

et al. 2017

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Wireless neural stimulators are being developed to address problems associated with traditional lead-based implants. However, designing wireless stimulators on the sub-millimeter scale (<1 mm3) is challenging. As device size shrinks, it becomes difficult to deliver sufficient wireless power to operate the device. Here, we present a sub-millimeter, inductively powered neural stimulator consisting only of a coil to receive power, a capacitor to tune the resonant frequency of the receiver, and a diode to rectify the radio-frequency signal to produce neural excitation. By replacing any complex receiver circuitry with a simple rectifier, we have reduced the required voltage levels that are needed to operate the device from 0.5 to 1 V (e.g., for CMOS) to ~0.25–0.5 V. This reduced voltage allows the use of smaller receive antennas for power, resulting in a device volume of 0.3–0.5 mm3. The device was encapsulated in epoxy, and successfully passed accelerated lifetime tests in 80°C saline for 2 weeks. We demonstrate a basic proof-of-concept using stimulation with tens of microamps of current delivered to the sciatic nerve in rat to produce a motor response.

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Section: Introductionmentioning

confidence: 99%

A Sub-millimeter, Inductively Powered Neural Stimulator

et al. 2017

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“…However, activation of the primary device at power levels several times higher than the supra maximal level may be needed due to the fact that the implanted stimulators will move along with the neural tissue with respect to the optical fiber delivering the light power. We envision attaching the fiber optic to some bony structure outside the CNS for chronic applications (Sahin and Pikov, 2011). Thus the devices may move in and out of focus when the spinal cord or the brain moves with respect to the vertebrae or the skull, respectively.…”

Section: Discussionmentioning

confidence: 99%

“…Additionally, radio-frequency radiation is seen as a potential wireless paradigm for transferring power and data, but it requires the use of a coil that is typically in the millimeter size range (Harrison et al, 2007). Current wireless stimulation paradigms are reviewed by Sahin and Pikov (2011).…”

Section: Introductionmentioning

confidence: 99%

Improved selectivity from a wavelength addressable device for wireless stimulation of neural tissue

et al. 2014

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Electrical neural stimulation with micro electrodes is a promising technique for restoring lost functions in the central nervous system as a result of injury or disease. One of the problems related to current neural stimulators is the tissue response due to the connecting wires and the presence of a rigid electrode inside soft neural tissue. We have developed a novel, optically activated, microscale photovoltaic neurostimulator based on a custom layered compound semiconductor heterostructure that is both wireless and has a comparatively small volume (<0.01 mm3). Optical activation provides a wireless means of energy transfer to the neurostimulator, eliminating wires and the associated complications. This neurostimulator was shown to evoke action potentials and a functional motor response in the rat spinal cord. In this work, we extend our design to include wavelength selectivity and thus allowing independent activation of devices. As a proof of concept, we fabricated two different microscale devices with different spectral responsivities in the near-infrared region. We assessed the improved addressability of individual devices via wavelength selectivity as compared to spatial selectivity alone through on-bench optical measurements of the devices in combination with an in vivo light intensity profile in the rat cortex obtained in a previous study. We show that wavelength selectivity improves the individual addressability of the floating stimulators, thus increasing the number of devices that can be implanted in close proximity to each other.

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“…Percutaneous wires present a pathway for infection (Hargreaves et al 2004) and implanted wires can also limit the ability of the stimulators to move with the tissue, leading to a foreign body response or loss of contact with the target tissue (Roy et al 2007;Markwardt et al 2013). Additionally, chronic stress and strain on wires, particularly for devices in the periphery, can lead to failure in the wire itself or its connection to the stimulator (Sahin & Pikov 2011). In small animals like rats and mice, wires used to power neural stimulators can interfere with natural behavior, particularly when studying social interaction between multiple animals (Pinnell et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Magnetoelectric materials for miniature, wireless neural stimulation at therapeutic frequencies

Wickens

Avants

Verma

et al. 2018

Preprint

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A fundamental challenge for bioelectronics is to deliver power to miniature devices inside the body. Wires are common failure points and limit device placement. On the other hand, wireless power by electromagnetic or ultrasound waves must overcome absorption by the body and impedance mismatches between air, bone, and tissue. In contrast, magnetic fields suffer little absorption by the body or differences in impedance at interfaces between air, bone, and tissue. These advantages have led to magneticallypowered stimulators based on induction or magnetothermal effects. However, fundamental limitations in these power transfer technologies have prevented miniature magnetically-powered stimulators from applications in many therapies and disease models because they do not operate in clinical "highfrequency" ranges above 50 Hz. Here we show that magnetoelectric materials -applied in bioelectronic devices -enable miniature magnetically-powered neural stimulators that can operate up to clinically-relevant high-frequencies.As an example, we show that ME neural stimulators can effectively treat the symptoms of a hemi-Parkinson's disease model in freely behaving rodents. We further demonstrate that ME-powered devices can be miniaturized to mmsized devices, fully implanted, and wirelessly powered in freely behaving rodents. These results suggest that ME materials are an excellent candidate for wireless power delivery that will enable miniature bioelectronics for both clinical and research applications.

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Wireless Microstimulators for Neural Prosthetics

Cited by 23 publications

References 81 publications

A Sub-millimeter, Inductively Powered Neural Stimulator

A Sub-millimeter, Inductively Powered Neural Stimulator

Improved selectivity from a wavelength addressable device for wireless stimulation of neural tissue

Magnetoelectric materials for miniature, wireless neural stimulation at therapeutic frequencies

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