New material helps wounds heal quickly

When we injure ourselves, or undergo surgery, tissues have to stitch themselves back together. And as this happens, the chemical environment of the wound, and the types of cells that are present, go through a sequence of changes. And what helps healing at one stage won’t necessarily be the best promoter of repair later on. Instead, what’s needed is a chemically intelligent repair material that can supply just what the repair process requires just when it wants it. And Ben Almquist, at Imperial College London, has developed just such a material that uses parcels wrapped in DNA to dispense healing signals on demand; he explained to Hannah Laeverenz Schlogelhofer how it works.

Ben - So what we want to do is we want to design materials that can interact with our wounds as they heal. So, if you think about something like a bandage, it really just sits there and it doesn't actually interact with our wounds. And so what we want to do is design materials that can change and interact over time with the wound to promote and help wounds heal.

Hannah - How does this work?

Ben-  So we have developed a way for us to design materials that have kind of hidden instructions in them that cells can unveil when they need them. And those instructions can be specific to what those cells need to help heal a wound. So the best way to think about this is to think about getting home and seeing one of those packaging envelopes that has arrived for you and what you do is you take it and you pull on the tab to open it and then remove kind of whatever's inside. Our technology works in a very similar way. So we have these packages that are available within the scaffolding that cells crawl around in, and they can come and pull on them and release these instructions and activate these instructions that tell them what to do.

Hannah - So what are these envelopes made of?

Ben -  These envelopes are made out of DNA. Most people think of DNA with genes and things like that but it can be developed and used as a material because it has very specific interactions. And so we can use it kind of like a programmable material to build with. And so what we do is, by using a single strand, it folds up into a little three dimensional shape, kind of like tying a bow, and this bow then interacts very specifically with a protein of interest. So these proteins can do a variety of different things. Depending on the protein that we target, they could, let's say, promote blood vessels growing or promote cells that build more scaffolding to come into the wound or in the case of something like bone they might promote bone growth and mineralization.

Hannah - And so how do you make sure that this envelope opens at the right moment?

Ben - So one way we can do this is by tuning it to which cells are present in the wound as it heals. So if you think about wound healing when you first have a wound there is one type of cell, let's say from your immune system, that helps kill off bacteria and removes some of the damaged tissue that's there. But then over time the cells that are present change. And so what we can do and what we have shown is that we can design it so that different packages can be opened by different types of cells.

Hannah -  Once the wound heals what happens to the material after that?

Ben - So one of the nice things about this is that it's made out of DNA and inherently our bodies know how to deal with DNA. And so as the wound heals you can have it so that it breaks down in our cells and our bodies know how to get rid of it and recycle it.

Hannah - What are the next steps for this research.

Ben - Currently the next step of this is that we're testing this in the context of broken bones that don't heal. And so we have a model system where we can actually put these in and see whether or not we can heal these defects that normally don't heal. But then going forward this will provide the kind of foundational research that we need to begin exploring transitioning this to the clinic.

There's a lot of benefits of this strategy: it's highly flexible, it's highly programmable and there's a lot of benefits too from being DNA which every year gets cheaper and cheaper to make. And one of the nice things is that it uses this DNA that is already used clinically and so there's a background that's available in terms of - are these safe, are they effective? And so we're hoping that we can leverage that a bit to speed up the transition to the clinic.