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Innovations in Wireless Bioelectronics for Precision Medicine, from Sustainable Sweat Sensing to Ingestible Gut Monitoring


Min, Jihong (2024) Innovations in Wireless Bioelectronics for Precision Medicine, from Sustainable Sweat Sensing to Ingestible Gut Monitoring. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/kcm7-wz71.


Biofluids, constituting about 60% of the human body, serve as treasure troves of biomarkers such as metabolites and electrolytes, shedding light on individual health conditions. Although blood and urine tests have been routinely utilized, they are limited by their invasive and episodic nature. However, the promise of continuous and noninvasive access to other biofluids like sweat, GI fluids, and saliva paves the way for real-time, onsite health monitoring. This thesis delves into the untapped potential of wearable sensors and noninvasive biofluid analysis, emphasizing the importance of continuous and sustainable monitoring for predictive personal healthcare. Chapter 1 introduces the paradigm of biofluid sensing, focusing on sweat as a key candidate for personalized healthcare applications. Chapter 2 delves into the physiology of sweat glands, highlighting the composition of sweat and the mechanisms behind sweat extraction, either through natural exercise or iontophoretic stimulation. Chapter 3 embarks on the development of innovative sensors designed for detecting clinically pertinent biomarkers in sweat, a step forward in predictive health analytics. In Chapter 4, the spotlight is on system integration, as the study emphasizes the need for miniaturized and reliable wireless sensor devices that ensure minimal discomfort and maximum reliability. Chapters 5 and 6 delve into strategies for sustainably powering wearable devices from energy harvested from body motions and from ambient light, respectively. The final chapter, Chapter 7, extrapolates the aforementioned technologies for the realm of ingestible devices, adapting them for electrochemical sensing in alternate media, primarily gastrointestinal fluids. This allows for enhanced detection of gastrointestinal diseases and a deeper understanding of the intricate gut-brain axis. The ultimate vision of this research is to equip individuals with wearable and ingestible sensors that can seamlessly monitor a broad spectrum of clinically relevant biomarkers. This continuous monitoring, coupled with data analytics, will potentially catalyze a shift from reactive to predictive healthcare, ushering in an era of personalized therapeutic interventions. As wearable sweat and ingestible sensors become mainstream, a confluence of biosensing mechanisms, materials science, and flexible electronics is anticipated enable continuous and unobtrusive acquisition of clinically relevant biomarkers over prolonged periods and large populations, further refining the nexus between health monitoring and precision medicine.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Wearable sensors, ingestible electronics, personalized healthcare, energy harvesting
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Medical Engineering
Thesis Availability:Not set
Research Advisor(s):
  • Gao, Wei
Thesis Committee:
  • Emami, Azita (chair)
  • Gao, Wei
  • Shapiro, Mikhail G.
  • Lester, Henry A.
Defense Date:14 November 2023
Funding AgencyGrant Number
Office of Naval Research (ONR)N00014-21-1-2483
Office of Naval Research (ONR)N00014-21-1-2845
Tobacco-Related Disease Research Program High Impact Pilot Research AwardT31IP1666
American Cancer Society Research ScholarRSG-21-181-01-CTPS
Record Number:CaltechTHESIS:12052023-185529151
Persistent URL:
Related URLs:
URLURL TypeDescription adapted for ch.1, ch.2, ch.3, ch.4 adapted for ch.2, ch.3 adapted for ch.2, ch.6 adapted for ch.3 adapted for ch.3 adapted for ch.5 adapted for ch.5 adapted for ch.5
Min, Jihong0000-0002-5788-1473
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:16255
Deposited By: Jihong Min
Deposited On:02 Jan 2024 20:24
Last Modified:02 Jan 2024 20:24

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