Radio-Frequency sensing Platforms with Graphene Oxide for Wireless Health Care System

In the past decade, graphene has been widely researched to improve or overcome the performance of conventional radio-frequency (RF) nano-devices and circuits.

In recent years, novel RF bio and gas sensors based on graphene and its derivatives, graphene oxide (GO) and reduced graphene oxide (rGO), have emerged as new RF sensing platforms using a wireless remote system.

Although the sensing schemes are still immature, this review focuses on the recent trends and advances of graphene and GO (rGO)-based RF bio- and gas sensors for a real-time and continuous wireless health care system.

Graphene, a single atomic sheet of sp2-bonded carbon, is a unique and exciting material from many perspectives.

The thinnest material possesses highly excellent properties, such as mechanical strength, electrical and thermal conductivity, optical transparency, chemical stability, and impermeability.

For these reasons, graphene has received significant attention as one of the most interesting materials for a wide variety of potential applications since its discovery in 2004.

In particular, graphene exhibits semi-metallic and electro-mechanical properties in a wide frequency range, including radio-frequency (RF). Research on graphene-based novel RF devices and circuits has been one of the main topics in the RF nano-electronics field.

For example, graphene with semi-metallic properties was produced by silkscreen printing for a highly conductive radio-frequency identification (RFID) tag antenna, similar to the silver antenna but with much higher stability.

Additionally, graphene was studied as a membrane of a frequency mixer, which converts low-frequency into high-frequency, and vice versa, for RF components.

Furthermore, graphene-based field-effect transistors (G-FETs) were developed with a cutoff frequency of 100 GHz. These are proven results as an emblematic protagonist and real solutions for state-of-the-art RF nanoelectronics.

In recent years, promising nano-material platforms based on graphene, such as the fundamental two-dimensional (2D) carbon structure with exceptionally high electronic quality and high chemical sensitivity, have emerged for many potential applications, such as bio, gas, chemical, molecular and infectious sensors.

In graphene-based biosensors, the latest example based on nanotechnology in health care is a graphene-based wireless sensor that can make 24-h health care easier to achieve by enabling wireless monitoring of various biomedical events to better assess the health care status of the wearer.

Graphene that detects chemical/molecular agents and lengths of exposure can be used as a lightweight and transparent wearable or bio-implantable electronic sensor. It can provide an inexpensive sensing scheme to detect in real-time the biomedical substance of interest.

Next, the pros and cons of these sensing schemes are analyzed, and finally, the challenges and prospects for robust RF sensing platforms in a real-time and continuous health care monitoring system are discussed and suggested.

The term RF means all science and techniques that are related to transmitting and receiving information or power in the free space (atmosphere) or transmission lines utilizing electromagnetic waves—so-called radio waves and microwaves—and the equipment, e.g., devices and circuits, needed therein for wireless communication.

MDPI Applied Sciences / ABC Flash Point Science News 2023.