Bioelectronic innovations, empowered by chemistry
Photos by Evan Krape March 03, 2023
UD Professor Laure Kayser received an NSF CAREER award to further her group’s materials science research
Whether it’s a smartwatch that can detect irregular heartbeats or a continuous glucose monitor, electronics that can interface with biology have already started to revolutionize the future of healthcare. But while the potential of these devices is far-reaching, the materials that make up future bioelectronics have to meet several different criteria — such as not causing damage or irritation to skin and avoiding toxic metals, for example.
Creating new organic, biocompatible materials that can interface with living systems is Laure Kayser, assistant professor in the Department of Materials Science and Engineering at the University of Delaware’s College of Engineering. Now, thanks to an award from the National Science Foundation (NSF), she and members of her lab will continue their fundamental research on a new class of polymers that could pave the way for future applications in human health.
The Kayser Lab specializes in designing, synthesizing and characterizing new plastics and polymers that can conduct electricity while safely interfacing with living systems. By working at the intersection of chemistry, polymer science and materials engineering, her lab is able to develop innovative design and synthesis approaches for creating new types of plastic materials.
Kayser, who holds a joint appointment in the Department of Chemistry and Biochemistry in the College of Arts and Sciences, said that what sets her group apart from others in the field of organic bioelectronics is a strong foundation in organic chemistry and their ability to make any material they want instead of only being limited to what’s currently available.
“We do modern chemistry, including chemistry that is not necessarily typically used in the field, and apply it to materials science,” said Kayser. “Because we have a background in chemistry and synthesis, we can make any material, characterize it, establish structure-property relationships and tailor it so the material can be interfaced with biology.”
Design rules for electronic highways and ionic waves
Starting in July, Kayser’s group will be investigating a new type of organic bioelectronic material. With a five-year, $654,206 Faculty Early Career Development Program (CAREER) award from NSF, her lab will study the fundamental properties of polymers that have properties inspired by living systems and also meet the criteria for being able to be incorporated into bioelectronic devices.
For this project, the lab will be studying derivatives of PEDOT:PSS. This polymer belongs to a class of materials known as organic mixed ionic electronic conductors, which have the unique ability to conduct both electrons and ions.
This is a necessary yet difficult to achieve property for bioelectronics: Typical electronic devices, such as laptops or cell phones, use electrons to transmit signals, while systems in biology, such as nerves, use ions. This difference in communication methods makes it difficult to “translate” signals from electronic devices into ones that a cell or organ can interpret.
There are also engineering challenges in creating this class of materials, Kayser explained. “There are very different design rules whether you want a material to be an electronic conductor or an ionic conductor,” she said. “For example, electronic conductors are very well ordered — like a highway for electrons to travel down. But if you want to make a good ionic conductor, ions usually like to be on a floppy, almost liquid environment, so more like a wave.”
Members of the Kayser lab, including doctoral students Chun-Yuan Lo, Vidhika Damani, Dan My Nguyen, and Elorm Awuyah, were instrumental in getting preliminary results for the proposed research. The team recently published a paper in Polymer Chemistry (which was also featured on the journal’s May 21st 2022 cover), where they determined the role of different chemical properties in PEDOT:PSS and how they could be changed to make the material more efficient in bioelectronic devices, a key finding that showcased how the group’s expertise in this field could be applied to PEDOT:PSS.
Through the CAREER award, the lab will continue studying derivatives of PEDOT:PSS to gain a solid, fundamental understanding of how to control both electronic and ionic conduction. The long-term goal is to develop design rules for fabricating bioelectronic devices with this class of materials in the future.
“Our lab’s focus is to understand deeply how chemical structures affect the electronic properties of those materials,” said Kayser. “Through this grant, we're going to learn a lot about these materials — some of these ideas might fail, but we’ll learn something along the way.”
Materials science outreach and education
With this CAREER award, Kayser will also be leading different outreach and educational initiatives for both high school students and undergraduates.
Part of this work will include connecting with female students at local high schools. This will be done through both a materials science-focused outreach program as well as a mentorship program, where graduate students and senior undergraduate students will be paired with high school students to provide support throughout the college application process.
Kayser will also be working with Sheldon Hewlett, an assistant professor who leads instruction and teaching in the materials science and engineering department, on integrating research into undergraduate curriculum. With support from the CAREER award, junior year materials science students will conduct a polymerization of PEDOT:PSS, including synthesis, purification and characterization, as part of a laboratory module. There will also be opportunities for students to address additional research questions during the course module, as well as funded research programs for those who are interested in carrying their work into the summer.
Along with introducing students to the process of polymerization, Hewlett added that this project will allow students to work with a class of materials in a laboratory course that they are likely to encounter in their career. “Not only will this award give us an opportunity for students to do real research, but it also provides students with a novel material system to work with,” said Hewlett. “You don’t see a lot of lab courses working with these polymers at this level — of making a material from start to finish, and then characterizing it afterwards.”
Making new discoveries through 'great fundamental science'
"Chemistry will be central to the discoveries that Laure Kayser’s research group will advance on plastics and other polymeric materials through this NSF CAREER award,” said Joel Rosenthal, professor and chair of the Department of Chemistry and Biochemistry. “Rather than simply tweaking or studying materials that already exist, the Kayser lab is adept at leveraging synthetic chemistry to discreetly control the composition, and by extension, the properties of new polymers for various applications, including bioelectronics. I’m incredibly excited to see how her group's work will continue to develop over the next several years."
Joshua Zide, professor and chair of the Department of Materials Science and Engineering, added, “Professor Kayser is a fantastic contributor to the Materials Science and Engineering Department, and we are lucky to have her. Her research translates the chemistry to myriad important applications, and the perspective she brings is a huge benefit to the whole department.”
While Kayser is excited about the potential of her research to potentially impact a wide range of applications and fields, she is also looking forward to the “great fundamental science” that this CAREER award will enable her group to do.
“It's a relatively hot area that is going to continue growing, so it's a good place for us to be leading the pack,” she said. “I’m hoping that by learning more about the fundamentals of these materials, it might inspire others to explore different molecular designs and how they can be translated into devices. Overall, I think we’re going to make lots of really cool discoveries.”