Development of an Integrated EEG/fNIRS Brain Function Monitoring System.

In this study, a fully integrated electroencephalogram/functional near-infrared spectroscopy (EEG/fNIRS) brain monitoring system was designed to fulfill the demand for a miniaturized, light-weight, low-power-consumption, and low-cost brain monitoring system as a potential tool with which to screen for brain diseases. The system is based on the ADS1298IPAG Analog Front-End (AFE) and can simultaneously acquire two-channel EEG signals with a sampling rate of 250 SPS and six-channel fNIRS signals with a sampling rate of 8 SPS. AFE is controlled by Teensy 3.2 and powered by a lithium polymer battery connected to two protection circuits and regulators. The acquired EEG and fNIRS signals are monitored and stored using a Graphical User Interface (GUI). The system was evaluated by implementing several tests to verify its ability to simultaneously acquire EEG and fNIRS signals. The implemented system can acquire EEG and fNIRS signals with a CMRR of -115 dB, power consumption of 0.75 mW/ch, system weight of 70.5 g, probe weight of 3.1 g, and a total cost of USD 130. The results proved that this system can be qualified as a low-cost, light-weight, low-power-consumption, and fully integrated EEG/fNIRS brain monitoring system.

Low-noise Transimpedance Amplifier Design using Chopper-stabilized Technique for Nanopore Applications.

This paper presents a low-noise transimpedance amplifier (TIA) employing chopper-stabilized technique for nanopore applications. The TIA, which is used as a headstage for the monitoring system, must achieve low-noise performance to accurately measure a minute ionic current signal generated from the nanopore. In this work, we analyze detailed input- referred noise current of the capacitive-feedback TIA and propose a core amplifier adopting the chopper-stabilized technique to effectively reduce flicker noise in a bandwidth of interest for nanopore applications. This proposed circuit schematic is designed by harnessing 0.35 $\mu \mathrm{m}$ CMOS process and is verified using elaborate simulation results.

Development of an intrafascicular neural interface for peripheral nerve implantation.

This paper describes an intrafascicular neural interface for peripheral nerve implantation. The flexible penetrating microelectrode array with varying lengths (vl-FPMA), interconnection cable, wireless recording and stimulator modules were designed and fabricated to detect neural signals from the peripheral nerves or to stimulate them. The vl-FPMA consisted of silicon needles and polydimethylsiloxane (PDMS) platform supporting the needles. The length of electrode needles varied from 600 to 1000 µm. The interconnection cable was fabricated as parylene-metal-parylene sandwiched structure. The wireless recording/stimulation modules were also developed and connected with the electrodes. The integrated system was implanted in the sciatic nerve of beagles and the recording capability of the integrated system was demonstrated successfully.