the subtle pressure change in the wrist pulse by utilizing the effective mechano-

sensitivity. They have also tested the wireless transmission of the detected wrist pulse

signal using a wireless signal transferring unit and they were able to achieve the dis­

playing of the wrist pulse signal on the screen of a smartphone. Hence, the developed

MOF-PVDF ferroelectret can be used in auto-powered electronics, real-time wearable

healthcare monitoring devices, and artificial intelligence.

14.5 Future Scope

This chapter has demonstrated that MOFs have great potential in wearable sensing and

nanogenerator applications. Owing to the multiple advantages of MOFs, there is scope

for translational innovation in standalone wearable sensing. This domain would parti­

cularly be attractive in the current healthcare scenario because of the avoidance of

complex energy generation devices like batteries and fuel cells. In addition, sensors based

on MOFs have been reported to have very low LOD, which makes them very useful in the

early-stage detection of diseases like cancer. To realize the potential of MOF for use in

biosensors powered by nanogenerators, large-scale processing techniques like 2D and 3D

printing, screen printing, and roll-to-roll forming must be introduced. These techniques

are widely reported for the large-scale fabrication of devices based on a wide variety of

materials [49]. Although these techniques have been reported for the fabrication of MOFs,

their applications towards nanogenerators and biosensors need to be studied. Another

perspective that needs to be studied is the use of flexible substrates for developing these

devices. Since these MOFs will be used for wearable applications, these sensors must

adhere to the skin surface. The interaction between MOFs and these flexible substrates

needs to be optimized to ensure the proper working of the devices. A large volume of

work has been carried out on the optimization of such substrates, and working out the

interaction of MOF-based active materials with flexible substrates holds the key to rea­

lizing the application of MOFs for use in biosensors powered by nanogenerators [50].

Since the application of 2D materials is being focused on all areas of research, many

interesting properties and high-efficiency materials can be obtained if 2D MOFs can be

synthesized for applications in wearable biosensors and nanogenerators. Such conducting

MOFs and their composites can be used as support materials also thus paving way for

highly efficient devices with a small number of constituent layers [51,52]. Due to their

high surface area and highly flexible synthesis strategies, MOFs can be used to construct

support electronics such as active components of flexible printed circuit boards (PCBs)

also. These PCBs hold huge promise during innovation in the device scale as conven­

tional PCBs will be hard to integrate with flexible sensors and nanogenerators [53]. MOFs

have already been reported for the construction of diodes, transistors which are very

common components of conventional PCBs [54]. If these systems can be integrated into

the flexible PCBs, an ecosystem based on MOFs can be constructed. The ability of ma­

terials to be used in all components of the ecosystem clearly shows its potential for

commercial applications. From all these instances, it can be concluded that the field of

MOF-based sensors and nanogenerators is still in its infancy and holds great potential for

translational research directed towards battery-free standalone sensors for healthcare

applications. Such sensors can form nodes of an IoT (Internet of Things)–based network,

which can be used for real-time tracking of the physiological anomalies of the wearer.

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