**4. Conclusions and future prospects**

This chapter has reviewed some examples of new trends of skin-worn enzymebased electrochemical systems, focusing on biosensors, BFC, and self-powered sensors. The existing systems provide significant advances toward the painless and point-of-care applications and personalized electrochemical biodevices, which was not possible without such new biodevices. However, researchers still face many challenges, such as electrochemistry, electrical wiring of enzymes, enzyme behaviors, the fabrication of stretchable electrodes, O2 fluctuations in biofluids, interferences, and difficulty in sweat extraction. Moreover, the workability and reliability of biodevices can be limited due to the limited fluctuating and volume of biofluids. In order to avoid frequent recalibrations, the stability of biodevices or self-calibration systems are also important. Precise electrochemical functions for on-skin applications are still very challenging. Therefore, it is required careful attention to address all challenges in order to advance such wearable technologies.

Although main skin-worn BFCs have been driven by glucose and lactate fuels, it is interesting to explore new opportunities, such as from alcohol-based BFCs, where the bioanode can be functionalized with alcohol dehydrogenases. Future efforts may be made to expand the spectrum of current concepts. New integrated devices can be achieved by designing multifunctional sensors that can provide informative series of personalized data. This will require the incorporation of big-data analysis and Internet of things (IoT) to build up integrated networks and personalized baselines of each wearer. Big data collected from networks and individuals can

**45**

**Author details**

Itthipon Jeerapan1,2

**Acknowledgement**

Hat Yai, Songkla, Thailand

La Jolla, California, United States

provided the original work is properly cited.

\*Address all correspondence to: itthipon.j@psu.ac.th

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

1 Department of Chemistry, Faculty of Science, Prince of Songkla University,

The author would like to acknowledge Hassler Bueno for proof reading.

2 Department of NanoEngineering, University of California San Diego,

*Wearable Skin-Worn Enzyme-Based Electrochemical Devices: Biosensing, Energy Harvesting…*

then warn the user whether the body is in a healthy and equilibrium state or not. It is expected that developing new electrochemical biodevices will eventually track "fingerprints" of various pathologies and disorders. This aims toward wearable systems for early disease diagnosis. Moreover, full closed-loop concepts such as biocomputing logic gate, sensing, and therapeutic systems can also be further exploited in the integration of biosensors, BFCs, and drug delivery devices, in order to obtain both diagnostic and therapeutic applications. The next success of wearable biodevices needs the hybrid of multidiscipline, including physiological medicine, electronics, electrochemistry, bio- and nanoengineering, and computer science. These continued collaborative efforts will open fantastic opportunities for addressing current challenges and step further to create novel wearable devices and acquire comprehensive big data. Ultimately, it is expected that innovative wearable electrochemical technologies and new findings will contribute to revolutionizing diverse

*DOI: http://dx.doi.org/10.5772/intechopen.85459*

personalized wearables and biomedical applications.

*Wearable Skin-Worn Enzyme-Based Electrochemical Devices: Biosensing, Energy Harvesting… DOI: http://dx.doi.org/10.5772/intechopen.85459*

then warn the user whether the body is in a healthy and equilibrium state or not. It is expected that developing new electrochemical biodevices will eventually track "fingerprints" of various pathologies and disorders. This aims toward wearable systems for early disease diagnosis. Moreover, full closed-loop concepts such as biocomputing logic gate, sensing, and therapeutic systems can also be further exploited in the integration of biosensors, BFCs, and drug delivery devices, in order to obtain both diagnostic and therapeutic applications. The next success of wearable biodevices needs the hybrid of multidiscipline, including physiological medicine, electronics, electrochemistry, bio- and nanoengineering, and computer science. These continued collaborative efforts will open fantastic opportunities for addressing current challenges and step further to create novel wearable devices and acquire comprehensive big data. Ultimately, it is expected that innovative wearable electrochemical technologies and new findings will contribute to revolutionizing diverse personalized wearables and biomedical applications.
