Highly Sensitive Self-Powered Biomedical Applications Using Triboelectric Nanogenerator

A 0.8 V, 14.76 nVrms, Multiplexer-Based AFE for Wearable Devices Using 45 nm CMOS Techniques

Wearable medical devices (WMDs) that continuously monitor health conditions enable people to stay healthy in everyday situations. A wristband is a monitoring format that can measure bioelectric signals. The main part of a wearable device is its analog front end (AFE). Wearables have issues such as low reliability, high power consumption, and large size. A conventional AFE device uses more analog-to-digital converters, amplifiers, and filters for individual electrodes. Our proposed MUX-based AFE design requires fewer components than a conventional AFE device, reducing power consumption and area. It includes a single-ended differential feedback operational transconductance amplifier (OTA) and n-pass MUX-based AFE circuits which are related to the emergence of low power, low area, and low cost AFE-integrated chips that are required for wearable biomedical applications. The proposed 6T n-pass multiplexer measures a gain of -68 dB across a frequency range of 100 kHz with a 136.5 nW power consumption and a delay of 0.07 ns. The design layout area is approximately 9.8 µm2 and uses 45 nm complementary metal oxide semiconductor (CMOS) technology. Additionally, the proposed single-ended differential OTA has an obtained input referred noise of 0.014 µVrms, and a gain of -5.5 dB, while the design layout area is about 2 µm2 and was designed with the help of the Cadence Virtuoso layout design tool.

Biophysical Sensors Based on Triboelectric Nanogenerators

Triboelectric nanogenerators (TENGs) can not only collect mechanical energy around or inside the human body and convert it into electricity but also help monitor our body and the world by providing interpretable electrical signals during energy conversion, thus emerging as an innovative medical solution for both daily health monitoring and clinical treatment and bringing great convenience. This review tries to introduce the latest technological progress of TENGs for applications in biophysical sensors, where a TENG functions as a either a sensor or a power source, and in some cases, as both parts of a self-powered sensor system. From this perspective, this review begins from the fundamental working principles and then concisely illustrates the recent progress of TENGs given structural design, surface modification, and materials selection toward output enhancement and medical application flexibility. After this, the medical applications of TENGs in respiratory status, cardiovascular disease, and human rehabilitation are covered in detail, in the form of either textile or implantable parts for pacemakers, nerve stimulators, and nerve prostheses. In addition, the application of TENGs in driving third-party medical treatment systems is introduced. Finally, shortcomings and challenges in TENG-based biophysical sensors are highlighted, aiming to provide deeper insight into TENG-based medical solutions for the development of TENG-based self-powered electronics with higher performance for practical applications.