A wounded human body relies on hidden healing proteins to mend itself, which in turn activate different types of cells that grow, multiply and put the sufferer on the road to recovery. But different stages of healing call on different types of cells, meaning one-dimensional materials made to promote general healing leave some room for improvement. Scientists have now come up with a molecule that can spur different cells into action along the way, enabling a new kind of dynamic healing technology that could be channeled into materials that respond to the task at hand.
The new technology was developed by scientists at Imperial College London's Department of Bioengineering and builds on an already approved type of molecule called an aptamer. These are single stranded DNA segments that bind to specific protein targets.
The researchers were able to make a customizable version of these by folding the DNA segments into three dimensional packages and attaching a customizable "handle" to the outside. They've dubbed these traction force-activated payloads, or TrAPs, and the idea is that as they crawl through collagen scaffolds around an injury site, (just like regular cells would do in the healing process), cells yank on them like an unraveling shoelace to activate the healing proteins.
But the interesting and novel part is the ability of this cellular "handle" to be changed so that different kinds of cells will grab onto it and pull the molecule open. It can therefore be tailored to trigger certain cells and release certain therapeutic proteins that may best help wound repair at different stages of the healing process.
The researchers were able to demonstrate this in the lab by working the TrAPs into collagen sponges, scaffolds and gels and selectively triggering various growth factors and cells. For instance, they were able to activate smooth muscle cells and not fibroblasts. Because they can be programmed to trigger different cells, the team imagines the TrAPs could be used for a range of injuries, from broken bones, to heart injuries to damaged nerves.
"This intelligent healing is useful during every phase of the healing process, has the potential to increase the body's chance to recover, and has far-reaching uses on many different types of wounds," says Ben Almquist, who led the research.
Because the technology is based on aptamers, which are already in use in various drugs, the team is hopeful that the TrAPs may find a relatively fast path to the clinic. Also working in their favor, they say, is the fact that they are simple to make and, because they are fully manmade, can be easily recreated in other labs and scaled up from there.
"TrAPs provide a flexible method of actively communicating with wounds, as well as key instructions when and where they are needed," says Almquist. "This intelligent healing is useful during every phase of the healing process, has the potential to increase the body's chance to recover, and has far-reaching uses on many different types of wounds. 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 published in the journal Advanced Materials.
Source: Imperial College London