No abstract

Optogenetics is a powerful technique that allows target-specific spatiotemporal manipulation of neuronal activity for dissection of neural circuits and therapeutic interventions. Recent advances in wireless optogenetics technologies have enabled investigation of brain circuits in more natural conditions by releasing animals from tethered optical fibers. However, current wireless implants, which are largely based on battery-powered or battery-free designs, still limit the full potential of in vivo optogenetics in freely moving animals by requiring intermittent battery replacement or a special, bulky wireless power transfer system for continuous device operation, respectively. To address these limitations, here we present a wirelessly rechargeable, fully implantable, soft optoelectronic system that can be remotely and selectively controlled using a smartphone. Combining advantageous features of both battery-powered and battery-free designs, this device system enables seamless full implantation into animals, reliable ubiquitous operation, and intervention-free wireless charging, all of which are desired for chronic in vivo optogenetics. Successful demonstration of the unique capabilities of this device in freely behaving rats forecasts its broad and practical utilities in various neuroscience research and clinical applications.

Optogenetics is an advanced neuroscience technique that enables the dissection of neural circuitry with high spatiotemporal precision. Recent advances in materials and microfabrication techniques have enabled minimally invasive and biocompatible optical neural probes, thereby facilitating in vivo optogenetic research. However, conventional fabrication techniques rely on cleanroom facilities, which are not easily accessible and are expensive to use, making the overall manufacturing process inconvenient and costly. Moreover, the inherent time-consuming nature of current fabrication procedures impede the rapid customization of neural probes in between in vivo studies. Here, a new technique stemming from 3D printing technology for the low-cost, mass production of rapidly customizable optogenetic neural probes is introduced. The 3D printing production process, on-the-fly design versatility, and biocompatibility of 3D printed optogenetic probes as well as their functional capabilities for wireless in vivo optogenetics is detailed. Successful in vivo studies with 3D printed devices highlight the reliability of this easily accessible and flexible manufacturing approach that, with advances in printing technology, can foreshadow its widespread applications in low-cost bioelectronics in the future.

Billions of neurons in the brain coordinate together to control trillions of highly convoluted synaptic pathways for neural signal processing. Optogenetics is an emerging technique that can dissect such complex neural circuitry with high spatiotemporal precision using light. However, conventional approaches relying on rigid and tethered optical probes cause significant tissue damage as well as disturbance with natural behavior of animals, thus preventing chronic in vivo optogenetics. A microscale inorganic LED (μ-ILED) is an enabling optical component that can solve these problems by facilitating direct discrete spatial targeting of neural tissue, integration with soft, ultrathin probes as well as low power wireless operation. Here we review recent state-of-the art μ-ILED integrated soft wireless optogenetic tools suitable for use in freely moving animals and discuss opportunities for future developments.

Robotic skin with human‐skin‐like sensing ability holds immense potential in various fields such as robotics, prosthetics, healthcare, and industries. To catch up with human skin, numerous studies are underway on pressure sensors integrated on robotic skin to improve the sensitivity and detection range. However, due to the trade‐off between them, existing pressure sensors have achieved only a single aspect, either high sensitivity or wide bandwidth. Here, an adaptive robotic skin is proposed that has both high sensitivity and broad bandwidth with an augmented pressure sensing ability beyond the human skin. A key for the adaptive robotic skin is a tunable pressure sensor built with uniform gallium microgranules embedded in an elastomer, which provides large tuning of the sensitivity and the bandwidth, excellent sensor‐to‐sensor uniformity, and high reliability. Through the mode conversion based on the solid–liquid phase transition of gallium microgranules, the sensor provides 97% higher sensitivity (16.97 kPa−1) in the soft mode and 262.5% wider bandwidth (≈1.45 MPa) in the rigid mode compared to the human skin. Successful demonstration of the adaptive robotic skin verifies its capabilities in sensing a wide spectrum of pressures ranging from subtle blood pulsation to body weight, suggesting broad use for various applications.