Professor David Kaplan, the chair of the Department of Biomedical Engineering at Tufts, has dedicated over two decades to his research in naturally produced silks, namely spider silk and silkworm silk. The Daily sat down with Kaplan to discuss his research and its applications.
The Tufts Daily: Why did you first get involved with research in spider silk?
David Kaplan: So many years ago, I read a paper about the mechanical properties of silks and I was intrigued by how strong they were … I was curious about how that was possible. That’s what got me interested and excited about learning about spider silk.
I had always had interest and was doing studies on biopolymers — materials produced by natural systems. That’s always been my area of interest in research since my graduate school days. When spider silks came along it was part of that theme but it was a new area to look at.
TD: What are some of the applications or benefits of spider silk?
DK: Spider silks themselves are useless in terms of applications because … there aren’t enough supplies of spider silk around today. All of the applications come from genetically engineered spider silk. The interest then is, from a fundamental perspective, trying to understand how silks are made and how to tailor the sequence of the protein itself to a specific function — what we call structure-function relationships.
We take that information and then we re-engineer it in new directions. That also brings in the fundamental interest of [whether we can] start to develop predictive models and tools so that we can tailor-make a spider silk for a given function — that’s part of the ongoing research. In terms of applications, we hope that [in the] long-term these will have utility in many areas of medical devices and material coatings.
TD: What is a specific example of an application of this research?
DK: For example, right now we use the silks we work with — not just spider silks, these are also silkworm silks — we use these to make orthopedic devices, devices that would help reattach ligaments and tendons … [that are] strong enough to do that but degrade away in the body over time to get away from the metallic devices used today that don’t degrade.
TD: Is it expensive to engineer these products?
DK: To make the synthetic spider silk — yes. We do it right now with the very inexpensive silkworm silk.
TD: Does the silkworm silk offer the same benefits as the spider silk?
DK: Much of it is the same … the real benefit is that you can get [silkworm silk] in large quantities so we can make medical devices right away, which is a lot easier and quicker. The spiders are better for what I said before — the fundamental understanding of structure-function. In terms of applications, it’s much easier to work with the silkworm silk.
TD: What is the student involvement like for this research?
DK: We have probably 20 different ongoing research projects … there are undergrad students to graduate students to post-docs. Each has a different project — so one is working on the orthopedic screws and plates I mentioned before, [while] another one on the other extreme is working on the genetically engineered spider silks to improve our understanding of the structure-function.
If a student comes to me and says, “Dave, I want to get involved in research,” I’ll say, “What are you interested in learning about?”… Once I know, I’ll have the undergrad go meet with the current students who are working on the project [most pertinent to their interests]. You try to match up the student’s areas of interest and where they want to learn with what the different project needs are.
TD: What major innovations have been made so far and what do you hope to accomplish in the future?
DK: We just had this National Geographic article about the screws and plates … I’d say we’re making major strides in the next generation of orthopedic medical devices, particularly for children, where bones are growing fast so you want something that’s going to degrade very quickly. The other is our brain project that was highlighted this year in the New York Times. We use the silk to make three-dimensional brain tissue that we use in the laboratory to study brain connectivity and to study brain trauma and to look at drug screenings. The idea is to build tissue models for laboratory study that avoid the use of animals and are better than just traditional cell cultures. I’d say those are two areas that we’ve made major progress [with] this year.