Accelerating wound recovery with advanced microtissue technology holds promise for treating severe or chronic injuries to soft tissues. Researchers at MIT Lincoln Laboratory’s Mechanical Engineering Group are developing new types of bioabsorbable fabrics that can mimic the unique way soft tissues stretch while nurturing growing cells.
Treating severe or chronic injury to soft tissues such as skin and muscle is a significant challenge in healthcare. Current methods can be costly and ineffective, and the frequency of chronic wounds is expected to rise due to conditions like diabetes and vascular disease, as well as an increasingly aging population.
The Limitations of Traditional Scaffolding Materials
One promising treatment method involves implanting biocompatible materials seeded with living cells (i.e., microtissue) into the wound. These materials provide a scaffolding for stem cells or other precursor cells to grow into the wounded tissue and aid in repair. However, current techniques suffer from a recurring setback: human tissue moves and flexes in a unique way that traditional soft materials struggle to replicate.
The Importance of Mimicking Tissue Un-crimping
‘The human body has this hierarchical structure that actually un-crimps or unfolds, rather than stretches,’ explains Steve Gillmer, a researcher at MIT Lincoln Laboratory’s Mechanical Engineering Group. ‘That’s why if you stretch your own skin or muscles, your cells aren’t dying. What’s actually happening is your tissues are uncrimping a little bit before they stretch.’
A New Approach: Knitted Microtissue
Gillmer and his team are working on creating new types of bioabsorbable fabrics that can mimic the unique way soft tissues stretch while nurturing growing cells. They have developed three basic knit constructions – interlock, rib, and jersey – which can move similarly to different types of soft tissue.
Knitted microtissues are a type of biomaterial engineered using electrospinning and knitting techniques.
These microstructures mimic the organization and properties of natural tissues, such as skin and muscle.
They consist of ultrafine fibers knitted together to create a three-dimensional network.
Knitted microtissues have shown potential in tissue engineering, wound healing, and drug delivery applications due to their high surface area, porosity, and biocompatibility.
Designing Knit Patterns for Tissue Repair
The team has conducted a number of tests embedding mouse embryonic fibroblast cells and mesenchymal stem cells within the different knit patterns and seeing how they behave when the patterns are stretched. Each pattern had variations that affected how much the fabric could uncrimp, in addition to how stiff it became after it started stretching.
Potential Applications
So far, the team has demonstrated a high rate of cell survival using these knitted microtissues. While their project began with treating skin and muscle injuries in mind, their fabrics have the potential to mimic many different types of human soft tissue, such as cartilage or fat. The team recently filed a provisional patent outlining how to create these patterns and identifies the appropriate materials that should be used.
Knitted microtissues are engineered tissues created by knitting together individual cells, typically using a combination of natural and synthetic materials.
These innovative biomaterials have numerous applications in regenerative medicine, tissue engineering, and biomedical research.
They can be designed to mimic the structure and function of native tissues, allowing for improved wound healing, tissue repair, and organ regeneration.
Knitted microtissues are also being explored for use in drug delivery systems, biosensors, and implantable devices.
Collaboration and Innovation
Gillmer emphasizes that this project has been a learning experience for him, highlighting the importance of collaboration between different branches of expertise. ‘Each branch of this team has a unique expertise, and I think the project would be impossible without them all working together,’ he says.
