A 0.9 g Battery-Free Wireless Stimulator with Infrared Communication for Applications in Neural Repair and Regeneration.

This paper presents the design of a 0.9 g battery-free wireless neural stimulator to electrically stimulate neural precursor cells for neural repair. The stimulator can deliver charge-balanced current-mode stimulation with fully programmable parameters. The stimulator current source requires a single transistor outside of a general-purpose low-power microcontroller. Wireless power transfer is used to eliminate on-device batteries to reduce device size and weight for use in small animal models, such as mice. A bidirectional infrared communication module is integrated to wirelessly control the device and update the settings of the stimulation parameters. A temperature sensor is integrated to monitor the heat generated by the power transfer. The whole design uses only low-cost off-the-shelf electronic components and consumes only 0.81 mA current while delivering 0.2 mA stimulation at 285.7 Hz. The prototype has been validated in vivo and successfully activated adult endogenous neural precursor cells in terms of eliciting significant expansion in stem cell pool. The stimulation effectiveness of the wireless device is comparable to that of a wired stationary instrument. The proposed design is applicable to a wide range of neuroscience experiments.