David Kaplan, Tufts University – Silk Medical Improvements

Metallic screws and plates have long been used in reconstructive medical procedures.

Dr. David Kaplan, professor of biomedical engineering at Tufts University, touts the potential benefit of replacing metal with silk in these surgeries.

David Kaplan holds an Endowed Chair, the Stern Family Professor of Engineering, at Tufts University. He is Professor & Chair of the Department of Biomedical Engineering and also holds faculty appointments in the School of Medicine, the School of Dental Medicine, Department of Chemistry and the Department of Chemical and Biological Engineering. His research focus is on biopolymer engineering to understand structure-function relationships, with emphasis on studies related to self-assembly, biomaterials engineering and functional tissue engineering/regenerative medicine. He has published over 600 peer reviewed papers and edited eight books. He directs the NIH P41 Tissue Engineering Resource Center (TERC) that involves Tufts University and Columbia University. He serves of the editorial boards of numerous journals and is Associate Editor for the ACS journal Biomacromolecules. He has received a number of awards for teaching, was Elected Fellow American Institute of Medical and Biological Engineering and received the Columbus Discovery Medal and Society for Biomaterials Clemson Award for contributions to the literature.

David Kaplan – Silk Medical Improvements

When you fracture bones or have ligaments and tendons that need reattachment to bone, most surgical repair options today depend on the use of metallic screws and plates.  These devices have a long history of success, yet they also have limitations.  

So, orthopedic surgeons are interested in  new medical hardware that avoid problems associated with metallic plates and screws.  In our recent work, we developed all silk protein-based orthopedic screws and plates.  These devices are unique and avoid the complications associated with metallic systems. 

Silk is already approved by the FDA for some medical devices, so orthopedic devices are a logical next step for this unique biomaterial. Unlike metal systems, silk screws are 100% degradable in the body. This avoids having to remove the hardware with a second surgery once the fracture is repaired.  This is particularly relevant in children whose bones grow quickly.   

The silk devices are also radiolucent so there is no interference with x-rays to track bone healing or security screening problems.  In terms of mechanics, metallic systems tend to be rigid. Silk biomaterials are stiff when dry, which allows ease of mechanical insertion into bone. But they soften upon hydration in the body to provide a better mechanical match to native bone tissue, thereby avoiding complications that can arise.

Silk systems also avoid the temperature sensitivity which can be a problem with metallic fixation.  Silk is also biocompatible, producing natural amino acids as it degrades.   Another useful feature of silk screws is that they can be easily functionalized with antibiotics or other therapeutics to enhance repairs or reduce infections at the surgical site. 

The  future for silk-based medical devices is very exciting, and our team and collaborators remain hard at work to study and develop the next generation of implantable devices based on silk