Researchers from Imperial College London have developed a new bioinspired material that interacts with surrounding tissues to promote healing. Materials are widely used to help heal wounds: Collagen sponges help treat burns and pressure sores, and scaffold-like implants are used to repair broken bones. However, the process of tissue repair changes over time, so scientists are looking to biomaterials that interact with tissues as healing takes place. Now, Dr. Ben Almquist and his team have created a new molecule that could change the way traditional materials work with the body. Known as traction force-activated payloads (TrAPs), their method lets materials talk to the body’s natural repair systems to drive healing.
The researchers say incorporating TrAPs into existing medical materials could revolutionise the way injuries are treated. This technology could help launch a new generation of materials that actively work with tissues to drive healing. After an injury, cells ‘crawl’ through the collagen ‘scaffolds’ found in wounds, like spiders navigating webs. As they move, they pull on the scaffold, which activates hidden healing proteins that begin to repair injured tissue. The researchers in the study designed TrAPs as a way to recreate this natural healing method. They folded the DNA segments into three-dimensional shapes known as aptamers that cling tightly to proteins. Then, they attached a customisable ‘handle’ that cells can grab onto on one end, before attaching the opposite end to a scaffold such as collagen.
During laboratory testing of their technique, they found that cells pulled on the TrAPs as they crawled through the collagen scaffolds. The pulling made the TrAPs unravel like shoelaces to reveal and activate the healing proteins. These proteins instruct the healing cells to grow and multiply. The researchers also found that by changing the cellular ‘handle’, they can change which type of cell can grab hold and pull, letting them tailor TrAPs to release specific therapeutic proteins based on which cells are present at a given point in time. In doing so, the TrAPs produce materials that can smartly interact with the correct type of cell at the correct time during wound repair.
This is the first time scientists have activated healing proteins using differing cell types in man-made materials. The technique mimics healing methods found in nature. Creatures from sea sponges to humans use cell movement to activate healing. This approach mimics this by using the different cell varieties in wounds to drive healing. This approach is adaptable to different cell types, so could be used in a variety of injuries such as fractured bones, scar tissue after heart attacks, and damaged nerves. New techniques are also desperately needed for patients whose wounds won’t heal despite current interventions, like diabetic foot ulcers, which are the leading cause of non-traumatic lower leg amputations.
TrAPs are relatively straightforward to create and are fully man-made, meaning they are easily recreated in different labs and can be scaled up to industrial quantities. Their adaptability also means they could help scientists create new methods for laboratory studies of diseases, stem cells, and tissue development. This technology could serve as a conductor of wound repair, orchestrating different cells over time to work together to heal damaged tissues. The research was funded by the Engineering and Physical Sciences Research Council and the Wellcome Trust.