Drawn-on-skin bioelectronics to seamlessly interface with the body
Restricted (Penn State Only)
- Author:
- Ershad, Faheem
- Graduate Program:
- Biomedical Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- June 06, 2024
- Committee Members:
- Cunjiang Yu, Chair & Dissertation Advisor
Xiaojun Lian, Major Field Member
Mark Horn, Outside Field Member
Xiao Liu, Major Field Member
Mehdi Kiani, Outside Unit Member
Yuguo Lei, Professor in Charge/Director of Graduate Studies - Keywords:
- bioelectronics
direct writing
drawn-on-skin
wearable electronics
stretchable/flexible electronics - Abstract:
- Recent advances in wearable bioelectronics, which attach directly to the epidermis, have highlighted pathways for health monitoring, disease prevention, and treatment. Despite their potential, existing wearable bioelectronics in the format of thin patches often suffer from motion artifacts due to inadequate adhesion and conformal interfacing with the skin. Addressing this critical challenge, I present the ultra-conformal, customizable, and deformable Drawn-on-Skin (DoS) bioelectronics platform. Due to the liquid nature of the DoS inks used for in situ fabrication and customization, DoS bioelectronics is robust to motion and capable of providing point-of-care therapy. This technological platform presents several advantages over existing wearable and/or printed bioelectronics including simple fabrication, multifunctionality, and immunity to motion artifacts without additional hardware or computation, thus offering a groundbreaking solution to a longstanding challenge in the field. Building on this new platform, the subsequent study focused on the biocompatibility of an improved DoS conductive ink, investigating its electrical and mechanical properties. Although in situ fabrication of electronic devices was minimally explored, studies on cytotoxicity and inflammatory responses to raw electronic materials at cellular, tissue, and organ levels were lacking. We developed fully biocompatible inks that can capture electrophysiological signals with high fidelity. Demonstrated across multiple cell types and tissues, the DoS ink showed biocompatibility with cardiomyocytes, neurons, mice skin, and human skin. The electrical performance of the ink was maintained under mechanical deformations, showcasing the potential for personalized, long-term electrophysiology. Further advancing the capability of this platform, the final study focused on the advantages of developing personalized multielectrode arrays (MEAs) that are unique to the subject’s muscle anatomies, compared to conventional technologies. Traditional electromyography (EMG) MEAs, constrained by fixed shapes and the inability to adjust in situ, often miss crucial muscle activity and suffer from data redundancy. I developed customizable and reconfigurable DoS MEAs, demonstrating the first high-density EMG mapping from in situ fabricated electrodes. These MEAs, adaptable to subject-specific muscle anatomy, reduce data redundancy and improve classification accuracy, illustrating a paradigm shift in wearable EMG technologies. Overall, this dissertation encapsulates the development of a versatile DoS bioelectronics platform that addresses critical challenges in wearable bioelectronics through a customizable manufacturing technique, diverse device functionalities, and demonstrations in sensing, stimulation, and human-machine interface applications. The presented work not only enhances the fidelity and functionality of bioelectronic devices but also forges a new path and standard for personalized healthcare technologies.