Flexible and Lightweight Devices for Wireless Multi-Color Optogenetic Experiments Controllable via Commercial Cell Phones

Abstract

Optogenetics provide a potential alternative approach to the treatment of chronic pain, in which complex pathology often hampers efficacy of standard pharmacological approaches. Technological advancements in the development of thin, wireless, and mechanically flexible optoelectronic implants offer new routes to control the activity of subsets of neurons and nerve fibers in vivo. This study reports a novel and advanced design of battery-free, flexible, and lightweight devices equipped with one or two miniaturized LEDs, which can be individually controlled in real time. Two proof-of-concept experiments in mice demonstrate the feasibility of these devices. First, we show that blue-light devices implanted on top of the lumbar spinal cord can excite channelrhodopsin expressing nociceptors to induce place aversion. Second, we show that nocifensive withdrawal responses can be suppressed by green-light optogenetic (Archaerhodopsin-mediated) inhibition of action potential propagation along the sciatic nerve. One salient feature of these devices is that they can be operated via modern tablets and smartphones without bulky and complex lab instrumentation. In addition to the optical stimulation, the design enables the simultaneously wireless recording of the temperature in proximity of the stimulation area. As such, these devices are primed for translation to human patients with implications in the treatment of neurological and psychiatric conditions far beyond chronic pain syndromes.

Fully Implantable Low-Power High Frequency Range Optoelectronic Devices for Dual-Channel Modulation in the Brain

“…Although a device may activate or deactivate in the presence of electromagnetic interferences or noises, the tunable nature ensures a robust device operation in a manner that extends the switching time long enough and therefore offers insensitivity to surroundings or environmental electromagnetic noises. Figure 2 g highlights the essential feature of the device, a low-power wireless operation for channel activation/deactivation, and comparisons with the power requirements for a multichannel operation enabled by µC embedded communication, NFC, or Bluetooth systems [ 14 , 15 , 16 ]. The measurement result reveals that the proposed logic circuit requires <300 µA for switching or channel selection, while the datasheet or white papers of µCs (ATTINY84A, ATMEL ® & MKL03Z32VFG4, NXP Semiconductors), NFC (M24LR64E-R, ST microelectronics), or Bluetooth (nRF51824, Nordic semiconductor) devices indicate at least 2.5 mA for a multichannel operation [ 17 , 18 , 19 , 20 ].…”

“…A multichannel operation can be accomplished by commercially available µC embedded communication systems, NFC, or Bluetooth chips. The benefit of employing these chips in implantable applications is their user-friendly interface and software, and/or “easily understandable” characteristics of HF range electromagnetic waves, allowing researchers with little or no expertise in RF electronics to utilize the technologies for their experiments [ 15 ]. However, these solutions demand considerable power requirements for a wireless operation (>10 mA or 30 mW), and the wireless TX system must deliver a transmitted power level of 8–12 W to activate the device in a cage [ 16 , 20 ].…”

“…Most existing wireless technologies allow for a single-channel operation in high frequency (HF)/ultra-high frequency ranges (UHF) or dual-channel operation in UHF ranges [ 9 , 10 , 11 , 12 , 13 ]. Microcontroller (µC) embedded communication systems, near field communication (NFC), or Bluetooth chips could achieve multichannel operation [ 14 , 15 , 16 ]. Although such wireless platform systems provide some utility with user-friendly software, the power requirements for wireless operation (~3 mA for a µC embedded communication system, ~3.5 mA for an NFC chip, and ~10 mA for a Bluetooth device) make them less ideal for small animal research or longitudinal experiments [ 17 , 18 , 19 , 20 ].…”

Interfaces with the peripheral nervous system for the control of a neuroprosthetic limb: a review

“…As for optogenetic stimulation, a fully implantable optoelectronic device which contains its own light source with a stretchable antenna that harvests wireless radio power has been developed, and it has shown promising results when tested to evoke pain sensation in mice [160]. A further fully implantable, battery-free, wireless optogenetic device equipped with tiny LEDs powered by resonant magnetic coupling has demonstrated its ability to excite opsin-expressing nociceptors in mice, and it can be operated by a smartphone [161].…”

Spontaneous and Induced Animal Models for Cancer Research

“…In addition, the adequate sites for tissue implantation have large area and layered structures, and this can favor the metastatic profile allowing cells networks development and movement [109]. Subcutaneous and orthotopic routes can be explored for implantation of different electronic devices or materials which can serve as therapeutic platforms including molecular levels evaluators [110].…”