• Chen's nano quest

    A greener medicine

    Jiawen Chen's molecular machines could change modern medicine. ‘Nano-scale machines can function in our body.’

    in short

    In January, Jiawen Chen was awarded a PhD for his thesis ‘Advanced Molecular Devices Based on Light-driven Molecular Motors’.

    Molecular machines in nature work to sustain life.

    ATP synthase, the energy source for the human body, is one kind of molecular machine.

    Chen’s research set out to recreate these organic machines in a lab setting.

    A molecular machine is like a car: when it moves, we only see the wheels turning. Chen’s work makes it possible to look under the hood.

    With Chen’s findings, it may be possible to develop medicine that deactivates once it leaves the body.

    full version

    Reading time: 8 min. (863 words)

    Sometimes, the work in a chemistry lab can be frustrating. Jiawen Chen worked on one experiment for several days, only to find out that there was an error in his reasoning. He realized he had to do the process all over again the next day.

    This scenario happened several times during Chen’s four year research. Thankfully, he persisted. What he found out will actually help to cure diseases in a more sustainable way one day.

    ‘It can be frustrating, but if you want to become a successful researcher, you have to accept it’, says Chen. He believes that if research in chemistry was easy, everyone would do it. ‘It gives you a challenge.’

    He says that researchers have to invest a lot of time into reading and thinking about their project, and only then deciding how to do the experiment to prove the argument. If they encounter difficulties, they need to go back and rethink. Researchers often have to repeat processes again and again.

    His dedication paid off. At the end of January, Chen was awarded a PhD for his thesis ‘Advanced Molecular Devices Based on Light-driven Molecular Motors’. He did his research project at the Stratingh Institute for Chemistry at the University of Groningen.

    New city

    When Chen was studying Chemistry in China, he encountered a textbook that featured professor Ben Feringa, who teaches Organic Chemistry at the RUG. Chen was impressed by his work – from that moment on, he wanted to study in Groningen.

    ‘I was really lucky to get accepted’, he says. Feringa receives hundreds of applications a month, but Chen’s application stood out because he provided a letter of recommendation from a Nobel laureate.

    When Chen received the offer from the RUG, he first had to Google where Groningen is located. He instantly fell in love with the city and the university. ‘The facilities here are amazing, so I could immediately start my PhD.’


    Chen gained ground-breaking insights when studying molecular motors. He explains that we have molecular machines in nature that are working to sustain our life. A very famous example is the ATP synthase: ATP is the energy source for the human body, and it is made with a molecular motor. But can only nature create these motors? Chen aimed to find out.

    ‘We wanted to simplify it’, says Chen. ‘We wanted to make a man-made motor.’ This molecular motor was supposed to mimic natural motors to some degree. Chen tried to build a model and, after a lot of work, got it to succeed. ‘Now, we begin to understand how molecular motors work.’

    This is connected to another important aspect of Chen’s work, which has to do with the molecule’s solubility in water. He says that 90 percent of organic molecules cannot dissolve in water and the artificial molecular motors are based on these. ‘A breakthrough in my thesis was that I made this molecule water soluble’, says Chen.

    He needed to make them soluble in water because this is what is happening inside our bodies. This was an important step in making the artificial molecular motor more similar to organic ones.

    Inside the molecule

    The next step for Chen was to visualize the artificial molecular motors. A molecule is really small in size and doesn’t emit light. When researchers wanted to see a molecule through the microscope, they would see a dark screen. By attaching a fluorescent group to the molecule, Chen was able to see it directly and ask it to do exactly what he wants.

    ‘This requires a lot of modern techniques and new technology.’ Now, chemists can study the mechanism of a single molecule. Chen compares it to a car: when it moves, we only see the wheels turning. We don’t know what is happening inside just by looking at the outside of the car. Chen is now able to see how a single molecule works inside.

    Chen also did a small project with liquid crystal droplets, also called smart materials. Smart materials are so named because they are responsive to external conditions without being monitored. For example, some offices are built today with windows that can react to changing weather: when the sun is shining, they can provide shade.

    In Chen’s research, he was able to make the liquid crystal droplets similarly react to the outer conditions. If he shines light on them, they enter one specific mode, ‘and if we apply heat, they can turn to another pattern’, says Chen. This is a pivotal study on how to build these smart materials.

    Cure diseases

    Why is all of this so important? In the near future, Chen’s research might help to cure diseases. ‘These nano-scale machines can function in our body’, he says.

    Modern medicine relies on a lot of antibiotics to fight diseases, but when they move out of the human body, they accumulate in the environment. That means that bacteria can eventually develop resistance against them.

    With Chen’s research findings, they can now develop medicine that’s only active in the human body – when they leave the body, they deactivate. ‘The idea is that these molecules can react to outer conditions.’ That means that the medicine will be harmless to the environment.

    Chen and other researchers are at the very beginning of developing this medicine, but thanks to his research, they’re already one step closer to solving one of the major problems in modern medicine.