Research

When researchers find inspiration in nature

Associate Professor Kaare Hartvig Jensen has a fundamental curiosity to know how our world works. By understanding living organisms or everyday phenomena and putting them into formula, he develops systems for drug delivery and makes knives with blades of paper.

Man studying a cactus close up. Photo: Bax Lindhardt — Associate Professor Kaare Hartvig Jensen leads a research group that seeks to understand the basic principles that govern the behaviour of biological systems. Photo: Bax Lindhardt

Tuesday 17 December 2024

Miriam Meister

When media around the world this summer wrote about research that had revealed which type of paper gives the worst paper cuts, it sounded like something out of a newspaper satire section. But it wasn’t. Behind the research are Kaare Hartvig Jensen and a couple of DTU colleagues, who have identified paper of about 65 micrometers thick as the most dangerous.

The idea to investigate a phenomenon that most people know all too well, but probably just curse at and perhaps put a band-aid on, came about during the corona lockdown, when the associate professor had extra time to read—and was exposed to more paper cuts than usual.

“It was probably the fact that I was annoyed at cutting my fingers combined with an intuition that it’s a well-defined scientific question that you would be able to find an answer to,” explains the physicist.

Curiosity as driving force

It is Kaare Hartvig Jensen’s very nature to investigate everyday phenomena in order to understand their inner workings—and he finds time for it every week in his well-organized calendar.

This curiosity makes him part of a long tradition that French scientists in particular have carried on, and which to this day makes researchers study, for example, how soap bubbles get their shape, or why necklaces hang around a neck like they do.

“It’s a tradition where various well-known researchers have spent some of their time studying some very simple problems to everyday problems. It is basically a desire to understand our surrounding world better, without making the matter too complex,” he elaborates.

The researchers have used knowledge from the paper cut project to make a cheap scalpel (a plastic handle with a paper blade 65 micrometers thick) that can cut meat and vegetables—and gelatin, which was the medium the researchers had to use in the absence of test subjects willing to expose their fingers to the study.

Intro screen from video explanation the paper cut study. — A video from Associate Professor Kaare Hartvig Jensen's research group explains why some types of paper give worse paper cuts than others - and reveals which paper gives the worst paper cuts.

Curiosity turned into patents

Most of Kaare Hartvig Jensen’s working time is, however, spent on projects where earmarked funds are translated into knowledge that expands our understanding of the world and is published in scientific journals—and which sometimes paves the way for inventions for the benefit of people.

Together with colleagues from MIT and Cornell University, he has, for example, solved the puzzle of how large trees can transport sugar syrup all the way to the leaves without having a pump. They have used this knowledge to develop a chip that can copy the mechanism—a patent-pending invention which in the long term could be used to ensure the right flow in fluid transfers.

“My favourite way of working is for us to start with a basic phenomenon, and then we come up with an application for it, instead of the long-term pursuit of solving a very specific problem where you know the problem in advance which can create a very linear way of thinking. And then if it doesn’t fit, if it doesn’t become a knife, then we can’t use that knowledge for anything, because it’s not a knife,” explains Kaare Hartvig Jensen.

Answers in nature

His desire to know how our world works often leads the associate professor out into nature:

“If you go out and study what living organisms do, they solve a whole lot of problems in ways that we can copy in solving the various technical problems we humans encounter. Nature is an infinite reservoir of inspiration for engineers or designers.”

In 2020, for example, he and his colleagues published a scientific article on the principles behind nature’s design of stingers, needles, and spikes in animals and plants that sting. The researchers had studied more than 200 different razor-sharp objects made of very different materials and in all sizes—from the smallest viruses and algae, measuring only 50 nanometers (i.e. significantly smaller than a human hair), to the narwhal’s 2.5-metre-long tusk, which is the world’s longest animal tip.

Man standing in tall grasses looking at a sample that he is holding in his hand. — For Kaare Hartvig Jensen, nature is an endless reservoir of inspiration for engineers and designers. Photo: Bax Lindhardt

The reference work ‘On Size and Life’, which was published before the researchers began their studies, had stated the ratio between length and diameter of the perfect tip as 2 to 3. The DTU researchers’ studies, on the other hand, showed that the ratio is 1 to 1.

“So, of course you could say: So what? But where it gets really interesting is, for example, in a project we did with LEO Pharma, which makes treatments for dermatological conditions. They are very interested in making treatments as a kind of band aid you put on, which features tiny needles. The needles must be able to contain the right amount of a substance and be able to penetrate the skin, so design and size are extremely important—and therefore it really matters whether the ratio is 2 to 3 or 1 to 1,” explains Kaare Hartvig Jensen.

When you constantly spot phenomena that are interesting to explore and you spend long days producing new knowledge, your head tends to be exhausted at the end of the day. To maintain balance, the associate professor has started cycling in his spare time.

“Otherwise, your body can be a bundle of energy, while your head is completely drained. For me, biking solves the problem,” he says with a smile.

Man bikes through forested area. — Cycling is Kaare Hartvig Jensens way of tiring out his body spending all day deep in thought. Photo: Bax Lindhardt.

Learning from the best

DTU has been Kaare Hartvig Jensen’s base for most of his research career—with the exception of a two-year detour as a postdoc at the prestigious Harvard University. The time spent among some of the world’s most talented researchers has been a great source of inspiration.

“New ideas are generated at a much higher rate in such places,” explains the associate professor, who believes that working with many different ideas and approaches at the same time is something he has brought back to DTU.

“I don’t think I get more ideas than everyone else—but I’ve become aware of staying open and not working with the same method or in the same research area for many years.”

Dreams for the future

As Kaare Hartvig Jensen sits in his office at DTU Lyngby Campus, surrounded by textbooks and inventions, and is asked to put his hopes and dreams for the future into words, he says—after a long and thoughtful pause—that he wants to do something that is interesting and exciting in itself. Without it having to solve a specific crisis right here and now.

“I think a lot of research policy in Denmark is driven by a disaster-readiness mindset—but the problem with allocating too much research funding based on a such a mindset is that the real crises are often the ones we don’t see coming. And here, basic research, or curiosity-driven research, plays a vital role. Because the crises you can’t foresee are the ones you always have to prepare for, and examining all possible aspects of the world may in the long run be what provides the answer we need in a disaster we couldn’t foresee.”

Facts

Playground of ideas

Over the years, Kaare Hartvig Jensen has worked on lots of ideas—like these, which have been created in a Villum Experiment-funded project as an offshoot of an experience in his own living room.

Mini harvester

Chemical substances (so-called metabolites) in plants can be used to make perfumes, aromatics, medicines, and biofuels. Traditionally, plants have been harvested and processed to extract the valuable substances.

Kaare Hartvig Jensen’s research group has developed a ‘mini harvester’ that, aided by AI, can harvest the substances directly from the relevant cells in the plants. Using AI, the invention can find the cells, which are about as thick as a human hair. It could also be used to inject material into plants with high accuracy to modify them.

The ideal box

What started as a curiosity during the many board games with the family during the corona lockdowns, Kaare Hartvig Jensen and his colleagues have transformed into the formula for the optimal box. He wondered why the lid of some board games easily and at a steady pace slides into place when you put it on—while others slide down slowly and unevenly.

Product designers could use this knowledge to make cardboard boxes that open and close easily and quickly, without gaping so much at the sides that the contents could fall out.

Contact

Kaare Hartvig Jensen Associate Professor Phone: +45 45252749 Mobile: +45 22315241 khjensen@fysik.dtu.dk