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Researchers at the University of Birmingham’s School of Chemistry recently announced the creation of a new thermoplastic biomaterial that could have broad applications for orthopedic technologies. Lead Researcher Josh Worch, Ph.D., and Professor Andrew Dove, Ph.D., described the biomaterial as “adaptable nylon,” and believe it could be applied to bone replacements and other medical devices involving minimally invasive surgeries that require flexibility in implant materials.
“This is a new class of biocompatible plastic that is as strong as nylons but is much easier to shape and manipulate due to its unique structural design, which is only accessible using our synthetic approach,” Dr. Worch said. Traditional non-resorbable biomaterials such as metal and composite present significant drawbacks ranging from costs to the risk of particle fragments breaking off inside the body. “We specifically addressed these challenges by creating a tough plastic with changeable mechanical properties (varying stiffness and/or stretchability), excellent processability, and shape-memory behavior. We believe this combination of properties makes the material very unique and attractive.”
“This material offers some really distinctive advantages over existing products used to manufacture medical devices such as bone and joint replacements,” Dr. Dove added. “We think it could offer a cost-effective, versatile, and robust alternative in the medical device marketplace.” The team of researchers claim that the material can be created through standard chemistry techniques and can be easily adjusted to suit the needs of unique products.
Drs. Worch and Dove and other researchers engineered the new biomaterial through the development of an organocatalyzed polymerization reaction in a lab at the University of Birmingham. According to Dr. Worch, the material is tolerant to both air and moisture, and doesn’t require high temperatures to produce, making it both user-friendly and scalable.
When asked about the level of confidence for the biomaterial retaining its shape inside the body over long periods of time, Dr. Worch said that his outlook is hopeful. “The research is still in preliminary stages (materials produced on ~20 g quantities with successful animal testing), but these results have been very promising. The recovered implanted samples from the animal testing were physically identical to the pre-implanted sample. This shows that no significant changes occurred to the material during implantation, albeit this one on a timescale of months and not years.”
The researchers also performed an intensive mechanical analysis of the material in a simulated biological environment, with early results showing the material initially softening in response to aqueous environments before quickly becoming stable again.
In the researchers’ findings, chemical similarities were found between implanted and pre-implanted sections of the material, a sign that indicates minimal biological interaction with the material’s chemical structure, according to Dr. Dove. “This was expected due to the polyamide-like backbone structure. Polyamides (or nylons) are known to be very resistant to hydrolysis and other chain-cleavage reactions.”
The team of researchers thinks that the new biomaterial is a promising candidate for orthopedic implants based on its ability to return to its original shape when heated, after being significantly molded and stretched. The creation of the plastic came about while researchers were exploring ways to manipulate the polyesters and polyamides that form nylons through a process called stereochemistry. A subdiscipline of chemistry, stereochemistry is the study of the spatial arrangement of atoms.
“It is a really fascinating material in its own right that can mechanically compete with conventional hard plastics (such as polycarbonates or acrylics, in addition to other nylons),” said. Dr. Worch, who believes that its shape-memory properties provide the added benefit of being repairable.
Now under a patent, the researchers plan to further test and explore the properties of the recently created biomaterial before teaming up with a suitable commercial partner.
