Abstract: A fully implanted integrated, wireless, flexible CMOS chip for long-term recording and stimulation of the brain in vivo and methods of manufacturing thereof are provided. The chip is an entire biocompatible system and can include the dense surface electrode array, the underlying CMOS integrated circuit architecture, integrated wireless powering and telemetry. Furthermore, miniaturization through manufacturing, permits implantation of the chip under the skull and other regions of interest with no wires or connections. Furthermore, these devices and systems can operate under a dual modality such as to be able to record and stimulate the surface of the brain and/or tissue in which they have been implanted.