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Laser-Engraved Wearable Sweat Sensor for Metabolic Monitoring


Yang, Yiran (Isabella) (2023) Laser-Engraved Wearable Sweat Sensor for Metabolic Monitoring. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/5yfm-tt16.


Wearable sensors have shown great potential in health diagnostics and monitoring. Continuous monitoring of metabolites in sweat could potentially offer great insight into a person’s health, but current sweat sensing technology faces challenges in different realms: The sensing strategies are limited and there is a need to achieve high sensitivity for low-concentration targets and widen the detection spectrum of chemical targets. The lack of efficient sweat sampling creates inaccurate sensing results from sweat mixing with skin contaminants or sensing byproducts. Moreover, the lack of evaluation of sweat metabolites with respect to relevant clinical conditions and the lack of scalable fabrication technique pose hurdles in the eventual applications of non-invasive sweat monitoring. In this thesis, efforts advancing progress in these fronts are presented. Chapter 1 establishes a brief topical overview of the sweat-sensing background. In Chapter 2, we demonstrate how to utilize laser-engraving technique to achieve high-performance graphene sensors for electroactive metabolite sensing and vital signs detection. Chapter 3 describes subsequent efforts built on laser-engraved graphene sensors to improve sensing selectivity and widen the detection spectrum to detect non-electroactive targets in sweat. In Chapter 4, design and performance of our laser-engraved microfluidics are described and shown to improve sweat sampling in both exercise-induced and iontophoresis-induced sweating individuals. Chapter 5 presents our endeavors in evaluating sweat biomarkers with clinical conditions in pilot studies involving individuals with gout and metabolic syndrome. In total, the works summarized here expand biology, chemistry, material science, and mechanical engineering, and could potentially facilitate future applications in precision nutrition.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Wearable Biosensors; sweat sensors
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Medical Engineering
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Gao, Wei
Thesis Committee:
  • Tai, Yu-Chong (chair)
  • Emami, Azita
  • Gharib, Morteza
  • Gao, Wei
Defense Date:17 January 2023
Record Number:CaltechTHESIS:02082023-162753604
Persistent URL:
Related URLs:
URLURL TypeDescription adapted for Ch. 1 and Ch. 4 adapted for Ch. 2 adapted for Ch. 2, Ch. 4 and Ch. 5 adapted for Ch. 3, Ch. 4 and Ch. 5
Yang, Yiran (Isabella)0000-0001-8770-8746
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:15102
Deposited By: Yiran Yang
Deposited On:17 Feb 2023 17:50
Last Modified:08 Nov 2023 00:25

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