Kaare Hartvig Jensen and his colleagues at DTU Physics have had repeated experiences where the small glass pipettes they use to extract fluid from plant cells have broken upon contact with the cell wall. This annoyed researchers and sparked their interest in similar sharp objects in nature that do not break when used. This includes thorns on plants such as cacti and nettles or the stings and thorns of many insects, algae, hedgehogs and other animals.
The idea of seeking inspiration in nature is not new to Kaare Hartvig Jensen, who belongs to a growing group of biomimicry researchers. They focus on exploring the design of nature to find inspiration for technical innovations related, for example, to medical tools and equipment.
Based on a wide range of experiences
To gain more knowledge on the subject, Kaare Hartvig Jensen and his colleagues conducted model experiments and collected data on more than 200 species, examining the design of various sharp objects in animals and plants. Their field of study was broad and included sharp parts of plants or animals that were used for very different purposes, such as sticking to a surface, ingesting food, or defending themselves. The scan further included needles or bites on animals and plants that are made of very different materials and sizes, ranging from the smallest viruses and algae spikes, measuring only 50 nanometers, to the pointed part of a longest animal in the world, the narwhal tusk of 2.5 meters. .
The researchers also included the design of sharp man-made objects such as nails, syringe needles, and weapons (ancient spears and spears) up to six meters in length.
Design ensures strength and elasticity
The large database allowed researchers to identify how nature’s sharp tools are designed to be both strong enough to penetrate human or animal skin, for example, and tough enough to ensure that the tip does not break. not in contact with the skin.
“Our results showed that there is a clear correlation between the length of a needle or prick and its diameter, both near the tip and where it attaches to the plant or to the needle. In this way, both the necessary strength and elasticity of the tip can be ensured, whether on a nettle or a mosquito ”, explains Kaare Hartvig Jensen.
“At the same time, it’s clear that nature’s sharp tools are at the limit of what is physically possible. And it’s also clear that the designs are very similar whether or not we look at the nanoscale spikes of a virus. or the beak of a swordfish 1.5 meters long, ”explains Kaare Hartvig Jensen.
The results of the new study were recently published in the scientific journal Physics of nature.
The study also included sharp, man-made objects that have already imitated natural forms to a large extent.
“This new knowledge of calculating the optimal design of a sharp object can in the future be used to design, for example, syringe needles to optimize drug allocation. Or in nail design, allowing a reduction in material consumption without losing the necessary stability “, explains Kaare Hartvig Jensen.
The researchers themselves also used the results to redesign their glass pipettes so that they no longer break when extracting fluid from plant cells.
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