Read on for the story of Dr Xiaogang Qu and his life-changing new designs. All words in bold can be found in the glossary at the end of the story. Questions and resources can also be found after the glossary. Happy reading!
Dr Xiaogang Qu is a chemistry researcher at the Chinese Academy of Sciences.
There, Xiaogang works with a team of other scientists. Some of them are very knowledgeable about chemistry, while others are biologists who study the human body. Together, this team has worked hard to produce new medicines. They combine their knowledge to produce new ways to help people heal.
Xiaogang is very interested in helping to protect people after they have been hurt. He knows that sometimes when people get injured, their wounds can be infected and made worse by tiny microorganisms called bacteria.
Bacteria are minuscule, far too small for us to see with just our eyes, so how can anyone study them? Luckily, Xiaogang works in a laboratory that has plenty of powerful microscopes. By zooming in on things under the microscope, he can identify the different bacteria that live on or in them.
There are lots of different types of bacteria. Not all of them cause people harm – in fact, some are helpful! Foods like yoghurt contain friendly bacteria, which help our digestive system work properly. Think that’s weird? What about this – some of the friendly bacteria inside your body has been living inside you ever since you were born!
We don’t meet the bad kinds of bacteria very often, mostly because we do lots of things to protect ourselves from them. Whenever you wash your hands or clean a surface, you’re getting rid of bacteria.
Plus, your body is working to protect you from them too! You have an immune system, which detects bad bacteria when they enter your body and kills them before they can make you ill.
Xiaogang is interested in bad bacteria. He knows that some bad bacteria can sneak past our body’s defences, and make us ill. This is especially easy for them at times when our body is already vulnerable.
Usually, bacteria can only enter our bodies through openings like our mouths and noses. However, when our skin is broken – for example, when we have a cut – bacteria can enter through this open wound and infect our body.
Xiaogang wanted to make sure that bacteria that get into wounds are noticed, so that they can be treated quickly, before the injured person becomes infected. We know from first aid that it’s always best to cover open injuries with a plaster or bandage to keep bacteria out, but what if we could go one step further? What if we could design a plaster that was able to tell uswhether there were any bacteria in the wound?
As a chemist, Xiaogang doesn’t study bacteria themselves (that’s the biologists’ job!), but he is great at creating solutions to the problems that they create.
Your body is essentially a massive chemical factory – as are the bodies of all other organisms, including bacteria. By studying the chemicals that bacteria produce, and learning how to respond to them, Xiaogang can work out how to fight what’s harmful, and support what’s good.
Xiaogang knew that we already have a way of physically keeping bacteria out of wounds – plasters and bandages. He also knew that we have a chemical way of treating bad bacteria that are inside the body – using medicine like antibiotics. We can put on a plaster straight away to keep dirt out, but medicine cannot be given until a person shows signs of infection. However, for a person to know that they are infected, bacteria have to cause quite a lot of harm. By the time people notice, the infection may have become serious.
“So”, Xiaogang wondered, “how could we combine a barrier, like a plaster, and a medicine, to make one solution that will make sure that infections are treated quickly?”
In the lab, he and his team worked hard to design a new material – something that could cover a wound to keep out bacteria, like a plaster, and also detect any harmful bacteria that had already sneaked in. They made sure their new design was easy to carry around, so that people could have them on hand – just like normal plasters!
Just like any other scientists doing research, Xiaogang’s team made predictions about how each element of the design would work. While they were in the lab, they had to scientifically test their design many different times, changing a small thing each time until it was perfect. By observing the design in action over a period of time, they were able to look for signs that it was working, or identify areas which needed improvement.
It was really important that Xiaogang spent lots of time carefully perfecting the design, because the plaster may eventually be used to prevent life-threatening infections. It’s vital that scientists test their work thoroughly and carefully, especially when working on things that can affect people’s health.
It wasn’t safe for Xiaogang to test the new plaster design on humans straightaway, because the team weren’t certain how effective their design would be. So, his first tests were on tomatoes, and then mice.
All the hard work put into testing paid off, and Xiaogang’s team managed to create a material that they were happy with! Through a long process of trial and error, they had managed to create a plaster that was able to detect bacteria in the wound. They called this final design “PBA” – a portable band-aid (a band-aid is the American word for a plaster).
Xiaogang’s plasters had one important new feature that is crucial to their success – when they detect the bad, infection-causing bacteria, they change colour! These ‘smart band-aids’ are green to begin with, but if they detect an infection, they change to yellow. This alerts the injured person, or their carer, to the problem, before bacteria have a chance to make them ill.
The plasters are able to identify infections in this way, because chemicals inside them are able to detect the acids that harmful bacteria produce.
In a similar way to you responding to a fire by pulling an alarm, Xiaogang’s plasters are able to respond to these acids, by producing chemicals that make the plaster change colour.
Even more impressively, if they detect an infection, the plasters release medicine to treat it, without anyone telling them to do so! That’s like you seeing a fire and instantly having water or a fire blanket handy to put it out quickly and safely, rather than leaving it to get worse while you find help.
If the bad bacteria are particularly nasty, and manage to survive this first wave of medicine, the plasters change colour again – this time to red. Again, this alerts the injured person, making sure that they go to a doctor to get the treatment that they need. Shining light on the bandage can be one way to get rid of these pesky drug-resistant bacteria!
This clever chemistry means that infections can be treated quicker than ever before, and that the effects of bad bacteria are less likely to go unnoticed. What an incredible design!
Soon, Xiaogang hopes that these plasters will be available for more and more people to use. They could be particularly important in countries where medical care is harder to access, or people are often wounded.
Chemistry is often about tiny substances, but it has a big impact. Though Xiaogang might spend most of his time in the lab with his microscopes, his designs will spread far and wide, helping people wherever they go!
Thank you for reading!
This story was written as part of a Masters in Science Communication project, investigating whether storytelling is an effective way to teach children about science and scientists. As a result, I would really appreciate some feedback, which you can give by answering a short survey. The survey takes less than 5 minutes to complete, and I will use the results to develop even better science stories in the future. To help, just click on the button below.
Xiaogang’s research paper: Sun, Y., Zhao, C., Niu, J., Ren, J., Qu, X. (2020). Colorimetric band-aids for point-of-care sensing and treating bacterial infection. American Chemical Society Central Science. 6: 207-212.
More information about Xiaogang’s work:
More information on bacteria and infections:
More information about animal testing:
The research was produced not just by Dr Xiaogang Qu, but also by the other members of their research team: Yuhuan Sun, Chuanqi Zhao, Jingsheng Niu, and Jinsong Ren. They too deserve credit for this discovery – good science is often best done as a team.
This story would not be nearly so good without its illustrations by the wonderful Alice Chen, and the advice and support of Dr. Nicola Hemmings. Thank you!