Meet the Researchers: Rebecca Keate

Rebecca Keate is a graduate student co-advised by SQI members Guillermo Ameer and Jonathan Rivnay. In this Q&A, Keate previews her Aug. 31 Rising Stars of SQI Lecture titled “Conductive Polymer Form Influences Composite Properties and Cell Response" (register here) and discusses her future research plans. 

How would you summarize your Rising Stars Lecture topic?

My research is mostly looking at how conductive polymers, which are organic electrically conductive materials, can be incorporated into new biomaterials and/or how they can enhance regeneration of different tissues. A major component of this is trying to understand how conductive polymers, and bioelectronic materials in general, change the electronic environments of cells and why it leads to differences in tissue engineering outcomes. One example is that we’ve seen conductive polymer loading alone can change cell differentiation patterns.

Are there any particular tissues that you are interested in, or are you testing these materials on all different types of tissue?

It’s pretty broad right now because a lot of the work that I do is on how the material characteristics change. Our bodies are so diverse that different tissue types have highly specific requirements, so by not specifying we can leave it more open initially and then see which material might be best suited for different types of tissue.

What inspired you to become a scientist in the first place?

I grew up in Chicago, and on a fifth-grade field trip to the Museum of Science and Industry, I saw an exhibit on medical devices. In particular, there was a balloon kyphoplasty device, which use balloons to reposition injured vertebrae. I thought it was the coolest thing that someone thought to use balloons in medical devices and I was really inspired by that novelty and creativity. Ever since then, I wanted to come up with similarly creative solutions and apply them to human health.

How did the opportunity arise to be part of both the Ameer and Rivnay laboratories, and what interested you in that path of being co-advised?

When I started at Northwestern in 2019, there was a postdoc, Anthony Petty, who was co-advised by both of them, so I was able to build relationships with both advisors and create an opportunity for myself to be co-advised.

I think having the expertise of both labs has been really important for my research. Jonathan is an expert in conductive polymers and their fundamental material properties, so his lab is very scientifically diverse. For example, there are people doing X-ray scattering at Argonne National Laboratory to understand the chemistry of conductive polymers at a fundamental level and there are also students characterizing new sensors and other biomaterials.

At the same time, Guillermo’s lab looks more at the clinical application of materials and he’s always thinking about what criteria materials need to satisfy in order to be clinically applied in regenerative engineering. I think having that balance has helped me better understand the physics of conductive polymers, especially in the context of how we can apply these materials to improve outcomes for patients.

You’ve coauthored three published papers since joining these labs, including two first-author papers. What do you think has enabled you to be so productive early in your time at Northwestern?

Much of the credit goes to having good collaborators and a lot of support. Anthony did a significant amount of work developing the chemistry for the projects that I work on, and there are a lot of great resources at Northwestern. There are numerous core facilities and really knowledgeable colleagues that have gone out of their ways to be helpful in troubleshooting techniques, experimental design, or confusing results with me.

The other thing is, I just enjoy working on the projects and have always been open-minded to the suggestions and input of my colleagues for new project directions. I think conductive polymers are really cool, and it always makes it easier to spend a lot of time on something when you like what you’re doing.

Of the three papers you’ve published, do any of them stand out as a highlight of your grad school career so far?

Of the work I have published so far, I would say the Chemical and Molecular Bioengineering paper was the biggest deal for me.

I’ve always been really interested in cartilage and bone regeneration, and in general I think conductive polymers have been underexplored in cartilage regeneration. To have that publication where we actually showed that conductive polymers enhance chondrogenic potential — or the potential to form cartilage — is one piece of information that will hopefully get the ball rolling for more possible applications.

Can you briefly summarize the key takeaways from that paper? 

We added a self-doped conductive polymer called PEDOT-S to a collagen sponge and we measured a marker for chondrocyte differentiation (cartilage tissue cells). We found that having the conductive polymer on the sponge significantly upregulated the cells’ production of that particular differentiation marker. In some later studies that weren’t published in the paper, I found that over longer periods of time SOX-9, which is a later-stage marker for chondrogenesis, was also upregulated when we added the conductive polymer to the collagen.

What research directions or applications are you interested in exploring going forward?

I’m currently working on functionalizing a novel citrate-based elastomer that was developed within the Ameer lab with conductive polymers. We are planning to load varying levels of conductive polymers to this material to measure how the conductive polymer might change the cellular response to the material. 

These studies are more focused on why or how the material properties — with or without conductive polymers — change cell differentiation. For example, is it possible to change the amount of conductive polymer that is loaded onto a substrate and see differences in how cells differentiate, and could we then create more complex patterns or regenerate more holistic tissue?

One of the current projects I’m working on is applying these materials for bladder regeneration in collaboration with Arun Sharma and John Rogers’ group.