Correlating the Effect of Dynamic Variability in the Sensor Environment on Sensor Design

Authors

Pulak BhushanFollow

Document Type

Dissertation

Degree

Doctor of Philosophy (PhD)

Major/Program

Electrical and Computer Engineering

First Advisor's Name

Dr. Shekhar Bhansali

First Advisor's Committee Title

Committee chair

Second Advisor's Name

Dr. Jean Andrian

Second Advisor's Committee Title

Committee member

Third Advisor's Name

Dr. Shubhendu Bhardwaj

Third Advisor's Committee Title

Committee member

Fourth Advisor's Name

Dr. Bruce McCord

Fourth Advisor's Committee Title

Committee member

Fifth Advisor's Name

Dr. Orlin Velev

Fifth Advisor's Committee Title

Committee member

Sixth Advisor's Name

Dr. Michael Daniele

Sixth Advisor's Committee Title

Committee member

Keywords

Wearable sensors, wound monitoring, electrochemical sensing, dynamic variability

Date of Defense

3-25-2021

Abstract

This dissertation studies the effect of biofluid dynamics on the electrochemical response of a wearable sensor for monitoring of chronic wounds. The research investigates various dynamic in vivo parameters and correlates them with experimentally measured behavior with wound monitoring as a use case. Wearable electrochemical biosensors suffer from several unaddressed challenges, like stability and sensitivity, that need to be resolved for obtaining accurate data. One of the major challenges in the use of these sensors is continuous variation in biofluid composition. Wound healing is a dynamic process with wound composition changing continuously. This dissertation investigates the effects of several in vivo biochemical and environmental parameters on the sensor response to establish actionable correlations. Real-time assessment of wound healing was carried out through longitudinal monitoring of uric acid and other wound fluid characteristics. A textile sensor was designed using a simple fabrication approach combining conductive inks with a polymeric substrate, for conformal contact with the wound bed. A −1 cm⁻², establishing the applicability of the sensor for measurements in the physiologically relevant range. The sensor was also found to be stable for a period of 3 days when subjected to physiological and elevated temperatures (37^oC and 40^oC) confirming its relevance for long-term monitoring. A direct correlation between sensor response and the dynamic parameters was seen, with the results showing a ~20% deviation from the accurate UA reading. The results confirmed that as a consequence of these parameters temporally changing in the wound environment, the sensor response will be altered. The work develops mathematical models correlating this effect on sensor response to allow for real-time sensor calibration. The clinical validation studies established the feasibility of UA measurement by the developed electrochemical sensor and derive correlations between the wound chronicity and UA levels. The protocols developed in this work for the design, fabrication, and calibration of the sensor to correct for the dynamic in vivo behavior can be extended to any wearable sensor for improved accuracy.

Identifier

FIDC009698

ORCID

https://orcid.org/0000-0003-1655-9389

Previously Published In

1. Songkakul, Tanner, et al. "Towards a long-term multi-site electrochemical wound monitoring system." 2019 IEEE SENSORS. IEEE, 2019.

2. Bhushan, Pulak, et al. "Biosensor for Monitoring Uric Acid in Wound and Its Proximity: A Potential Wound Diagnostic Tool." Journal of The Electrochemical Society 166.10 (2019): B830.

3. Bhushan, Pulak, et al. "Toxicity assessment of wearable wound sensor constituents on keratinocytes." Toxicology in Vitro 58 (2019): 170-177.

4. RoyChoudhury, Sohini, et al. "Multimodal Enzymatic Sensing for Continuous Wound Monitoring." ECS Transactions 88.1 (2018): 419.

Creative Commons License

This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License

Recommended Citation

Bhushan, Pulak, "Correlating the Effect of Dynamic Variability in the Sensor Environment on Sensor Design" (2021). FIU Electronic Theses and Dissertations. 4633.
https://digitalcommons.fiu.edu/etd/4633