Abstract:
Following the discovery of graphene, there has been extensive research on 2D materials, leading to a wide range of applications in the healthcare industry due to their unique properties, such as a high surface-to-volume ratio, nanometre-size layered structure, and bandgap tuning capabilities. In this chapter, we have categorized 2D material-based health sensors into three types: (i) Flexible sensors, (ii) Chemical sensors and (iii) Biosensors. Flexible sensors involve stretching or compressing 2D materials on flexible substrates to vary their resistance or capacitance, enabling the detection of body movements and heart rate. The deposition of mono or a few layers of 2D materials on thin, flexible substrates allows for conformal contact-like properties, facilitating proper and easy placement on the skin of the human body. Chemical sensors produce measurable electric signals when a molecule sits on its active layer. Using 2D material as the active layer enhances their sensitivity due to their thin nature and high surface-to-volume ratio. In biosensors, 2D materials are not used for directly sensing biomolecules due to incompatibility with inorganic molecules. Instead, bioreceptor layers are utilized on 2D material to detect the presence of biomolecules. The presence of 2D material provides a planar conducting channel for current transport in biosensors. The sensors discussed in this chapter primarily have field effect transistor device structures and exhibit responses in terms of current and resistance for monitoring human health indicators such as heart rate, glucose level, pH level and early detection of life-threatening diseases such as tuberculosis, cancer and more. This chapter delves into the applications, reliability, scalability, challenges and future applications of 2D materials such as graphene, transition metal dichalcogenides (TMDCs), MXenes and black phosphorus in healthcare systems.