Biohybrid material works like cartilage — ScienceDaily

Producing biomaterials that match the performance of cartilage and tendons has been an elusive goal for scientists, but a new material developed at Cornell demonstrates a promising new approach to mimicking natural tissue.

The results were published on July 8 at Proceedings of the National Academy of Sciencesand provide a new strategy for synthesizing clinical solutions for damaged tissues.

The tissue must be soft enough to bend and flex, but strong enough to withstand prolonged loading — for example, the weight a knee tendon must support. When tissues are worn or damaged, collagen hydrogels and synthetic materials have the potential to serve as substitutes, but none of them possess the right combination of biological and mechanical properties of natural tissue.

Now, Cornell researchers have created a biohybrid composite material with the essential characteristics of a natural tissue. The material consists of two main components: collagen — which gives the material its softness and biocompatibility — and a synthetic zwitterionic hydrogel, which contains positively and negatively charged molecular clusters.

“These charge groups interact with the negatively and positively charged groups in collagen, and this interaction is what enables the materials to dissipate energy and achieve high levels of durability,” said Lawrence Bonassar, the Daljit S. and Elaine Sarkaria Professor of Engineering Biomedical. in the College of Engineering and co-author of the study.

The biohybrid composite approaches the performance of articular cartilage and other biological tissues, possessing 40% more elasticity and 11 times the fracture energy—a measure of durability—of the zwitterionic material by itself.

Nikolaos Bouklas, assistant professor in the Sibley School of Mechanical and Aerospace Engineering and co-author of the study, said the material’s biocompatibility means it can recruit cells and keep them alive.

“Ultimately, we want to create something for regenerative medicine purposes, such as a piece of scaffold that can withstand some initial loads until the tissue is fully regenerated,” Bouklas said. “With this material, you can 3D print a porous scaffold with cells that can eventually create the actual tissue around the scaffold.”

In addition, the biohybrid material is self-assembled after the two components are mixed, Bouklas said, creating “the same interconnected network of collagen seen in natural cartilage, which would otherwise be extremely difficult to manufacture.” “.

The research brought together four research labs from three different departments thanks to a seed grant from the Cornell Center for Materials Research. The collagen used in the biohybrid composite was already under development in Bonassar’s lab, while the zwitterionic hydrogel was developed by study co-authors Robert Shepherd, an associate professor in the Sibley School, and Emmanuel Giannelis, the Walter R. Read Professor of Engineering in the Department of Science. and Materials Engineering.

The study authors are continuing to investigate the material and the molecular processes behind its synthesis. Bonassar said the material is suitable for the type of bioprinting seen in his lab, and the authors have begun experimenting with using it as a 3D printing material.

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Materials provided by Cornell University. Original written by Syl Kacapy, College of Engineering, courtesy of Cornell Chronicle. Note: Content may be edited for style and length.

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