Healing signals delivered by DNA packages

15 January 2019

x-ray of broken bone

x-ray of broken bone

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An intelligent material has been developed that can interact with a wound over time to help it heal...

“Wounds that don’t heal account for massive amounts of healthcare budgets, they’re one of the leading causes of amputation and they can have big impacts on quality of life,” says Ben Almquist from Imperial College London and lead author of the study published in Advanced Materials.

After an injury, or when we undergo surgery, tissues have to stitch themselves back together. As this happens, the environment of the wound goes through a sequence of changes. “If you think about wound healing, when you first have a wound there is one type of cell 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,” explains Almquist.

This means that what helps healing at one stage won’t necessarily be the best promoter of repair later on.

“If you think of something like a bandage, it just sits there and doesn’t really interact with our wounds,” says Almquist. “We want to design materials that can interact with our wounds as they heal.”

In order to create such a material, Almquist has taken inspiration from our body’s natural ability to heal. Like spiders in a web, cells navigate through the scaffold of a wound by latching on to specific protein fragments, or ‘handles’. The cellular pulling forces activate hidden healing proteins from within the scaffold that begin to repair the injured tissue.

To mimic this natural process, the team have designed a material based on DNA. “Most people think of DNA with genes,” says Almquist, “But it can be developed and used as a material because it has very specific interactions. We can use it like a programmable material to build with.”

A single strand of DNA is folded up into a three dimensional bow-like shape that binds to a specific healing protein of interest. One end of the DNA string is attached to the wound’s scaffold. At the other end, a ‘handle’ is added that is designed for a specific cell, meaning that only when the right cell comes along will it be able to latch on.

This material can be thought of like a DNA wrapped package. As cells move through the scaffold they take hold of the ‘handle’ and as they pull, the DNA package unfolds to reveal and activate the healing protein. These proteins act like an instruction that tells the cells what to do. “Depending on the protein that we target, they could 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 or mineralisation,” explains Almquist.

This new approach to using cellular forces to activate biological signals has the capability of releasing the right signals at the right time in order to boost the natural healing process. Currently this has been proven in the lab and next the team are planning to test it in a real harsh wound environment, before driving it forward so that it can have a real impact in the clinic.

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