(2l) High Density Soft Electronic Fibers

Biomedical devices with 1D geometry, such as surgical sutures, biopsy needles, endoscopes, guidewires, manometry probes, fiberscopes, and deep brain stimulation electrodes have been extensively used in the clinic for several decades. Compared to 3D systems and 2D thin films, 1D devices are more compact and flexible, making them favorable for deep penetration into tissues and body channels through minimally invasive implantation procedures. Furthermore, they can be readily retrieved and removed after completing sensing or therapeutic functions.

Among the prominent examples of 1D devices, electronic fibers have gained considerable attention owing to their compelling structural properties and diverse functionalities (e.g., sensing, tissue modulation, energy harvesting, and light emission). However, manufacturing electronic fibers poses challenges because they are incompatible with traditional microfabrication techniques designed for planar substrates. Consequently, currently available fiber devices suffer from drawbacks such as low density, limited functionality, and imprecise component positioning. Various approaches, including fiber spinning, 3D printing, (micro)fluidics, functionalization of commercial fibers, and thermal drawing, have been employed to fabricate 1D fiber devices. Although electronic fibers prepared by thermal drawing can potentially host tens of recording sites, the sensing/recording region is typically located at the tip of the fiber. Additionally, achieving high-density fibers with precise control over device structure, position, and orientation remains difficult. Add to this the tough requirement for compatibility with the thermal drawing process which considerably reduces the variety of materials that can be used.

In my postdoctoral work, I developed a method to prepare high-density electronic fibers that can host a variety of functional components. Briefly, we perform fabrication processes on a 2D substrate, which is subsequently transformed into a 1D structure. A suitable layout design is essential to achieving transformed electronic fibers (t-EFs) with precise control over the longitudinal, angular, and radial device positions. I demonstrated the advantages of our t-EFs for sensing and stimulation in the highly dynamic and loopy GI environment as well as neural recording in the brain. This work established a proof-of-concept for the transformation approach, opening up numerous future opportunities. From here, my envisioned future lab will lead the development of this emerging area of t-EFs by focusing on the following two directions:

• Developing and expanding the spectrum of t-EFs:

The transformation process I introduced during my postdoctoral research is still in its early stage. I intend to automate the transformation process for better control over device position, fiber structure, and size. Developing rolling machines will enable faster prototyping of fibers for any intended application, releasing time limitations that we currently have with the manual approach. Being able to create versatile on-demand fibers will hugely boost collaborative opportunities. One of our goals is to distribute custom-designed fibers for laboratories and research groups throughout the US and abroad, facilitating further testing and enabling advanced applications. My group will explore the material aspect of the transformed fibers (e.g., core materials: stretchable, bioresorbable, self-healing; and coatings: non-stick, tissue adhesive, etc.). We will explore new functions: sensing, modulation, actuation, delivery, energy harvesting and storage, and optical guiding. Furthermore, we are interested in the design and development of more intricate structures, including transistors and complex circuits (such as amplifiers and active matrix), for on-fiber signal manipulation and, ultimately, computing. These studies will involve comprehensive characterizations of mechanical, structural, and functional properties of the t-EFs.

• Implementation of t-EFs for various applications:

The versatility of the 2D-to-1D transformation approach presents a wide range of opportunities for diverse fiber applications. In the biomedical area, t-EFs are attractive as minimally invasive implantable systems. One compelling application is to utilize them as electronic sutures for wound monitoring (e.g., feedback about the healing process) and manipulation (e.g., electrical stimulation). Medical sutures used today are round in cross-section and range from 30 – 800 microns in diameter, posing a big limitation on the feasibility of on-suture micropatterning. My approach will stand out in this area and allow for suturing technologies that have not been realized before. On a different front, I also aim to develop methods for injecting and retrieving fibers into different target locations within the body, offering minimally invasive implantation and release procedures. Notably, the transformation process will allow the integration of micro-patterned components onto commercially available 1D medical devices (e.g., medical guidewires, biopsy needles, and endoscopes), something that can be readily translated into useful applications and allows expedited market entry.

The utility of the transformed fibers is not necessarily limited to implantable or biomedical devices. In fact, another attractive realm of applications would be in electronic textiles. Smart textiles, which already rely on fibers as a basic component would hugely benefit from electronic fibers. In my futures lab, we will study the incorporation of t-EFs into commercially available textiles (e.g., gloves) and eventually use for body or environmental monitoring. One attractive application would be to use fiber-equipped gloves for monitoring hand gestures through strain sensing and recording of muscle electrophysiological activity (e.g., EMG). This use of t-EFs with machine learning methods will allow accurate mapping of human performance in sports and other professions requiring motoric activities. Our devices, in their fiber form factor, offer advantages in terms of seamless integration into textiles and excellent mechanical compatibility. These characteristics are expected to contribute to the long-term performance and reliability compared to currently available options.

Teaching Interests

During my high school and undergraduate studies, I found little enjoyment in sitting through classroom lectures or listening to dry presentations. My interest would wane almost instantly as I became engrossed in my own imaginative pursuits. For a long time, I thought it was my idiosyncrasy, but very soon I realized that old-fashioned teaching methods do not fit my personality and fail to captivate my attention. This realization has shaped my perspective on teaching and made me value the utmost importance of offering active experiences that go beyond the mere delivery of information.

I have been extensively engaged in teaching across different educational levels Throughout my career. At Technion, I had my first in-class teaching experience and became the head teaching assistant in Thermodynamics and Mass and Heat Transfer. Here, I conducted tutorials for small groups, developed class materials, evaluated assignments and exams, and provided in-person meetings with students. Concurrently, I also taught the international class, where I implemented strategies to bridge cultural gaps and foster an inclusive learning environment. A key aspect of my approach was initiating random conversations before each tutorial to break social barriers. Another notable teaching experience was conducting the online course Nano Sensors and Nanotechnology through Coursera. While the course primarily targeted Technion students, it was also open to the public in both Arabic and English. This course has received a lot of attention in the media and became a subject of research about critical thinking and active student evaluation – a collaboration with Prof. Miri Barak from the department of Education in Science and Technology. Besides in-class teaching, I gave private tutors in chemistry, physics, and math. I was invited several times to give guest lectures in various educational activities (e.g., entrepreneurship day and open days for high school students at Technion). In Stanford, I took part in workshops delivered for high school students through the Stanford Nanofabrication Facility. These workshops covered a range of topics such as nanotechnology, photolithography, and functional materials, allowing me to share my knowledge and passion for these subjects with aspiring young minds.

Looking forward, my extensive interdisciplinary background in chemical engineering, materials science, and biomedical engineering equips me with the necessary expertise to teach a wide range of core courses within engineering departments. I am also eager to contribute to the field of bioelectronics by designing and delivering an advanced course in this exciting area. Given the rapid advancements in technology and its application in the biomedical domain, it is imperative to equip students with the knowledge and skills required to address the challenges in this interdisciplinary field. This course will focus on the state-of-the-art development in the field of wearable and implantable bioelectronics as well as relevant material preparation and device fabrication technologies.

At the heart of my teaching approach lie the following strategies. First, I will prioritize the development of a welcoming and inclusive class environment for students of diverse backgrounds. I firmly believe in teaching learning skills and thinking patterns instead of solely delivering information. To this end, I will promote active discussions by incorporating frequent, purposeful questioning to keep students engaged and deepen their understanding. My classroom will be like a practicing session of communication and open dialogues. To incorporate practical learning, I aim to integrate a few experimental sessions into my class (e.g., in the bioelectronic course: fabrication and lithography, tissue stimulation, and body monitoring). I expect these hand-on sessions to solidify theoretical knowledge and spark intellectual curiosity. I will encourage collaborative spirits between students by giving group assignments. I plan to create recorded video lectures for students to watch at their own convenience. This will free up class time for active learning activities like problem-solving in small groups, literature review, as well as guest lectures.