Spiders' Curling Iron, or Why They Don't Stick to Their Threads

The question of why spiders do not stick to their own threads triggered an international research project in which Jörn Bonse and Karin Schwibbert from the Federal Institute for Materials Research and Testing (BAM) were also involved. Their work focused on van der Waals forces, which are particularly relevant for very thin fibres. These forces are responsible for adhesion, i.e. ensuring that the fibre adheres to all surfaces. However, this is a problem when working with nanometre-thin materials, for example in the production of textile fleeces for breathing masks.

Inspiration from nature

The researchers found their solution in nature, in cribellate spiders. These spiders produce webs of ultra-thin nanofibres. To prevent themselves from sticking to the spider silk, they have a special organ on their hind legs called a calamistrum, Latin for curling iron. This organ has a fine superficial wave structure that prevents the silk from becoming a trap for the spider. This structure could also be transferred to technical surfaces by applying it to materials with a laser.

International collaboration and technology transfer

The team implemented the idea in a European Union FET Open project. This funding line supports high-risk, excellent research. Johannes Heitz from the Johannes Kepler University Linz coordinated the entire project, while the spinning know-how came from Anna-Christin Joel and her team at the RWTH Aachen University. At BAM, the special nanostructures were applied to steel, titanium, aluminium and other metallic materials using an ultrashort pulse laser. In Linz, it was shown that the adhesion forces could be reduced by up to 75 per cent by optimising the structure.

Fighting biofilms

Karin Schwibbert was also interested in the results, but from a different perspective. As a microbiologist, she studies bacteria on surfaces and their tendency to form biofilms. She discovered that special cell appendages on the outside of some bacteria play a crucial role in their contact with surfaces. Similar to spider silk, these appendages are made of proteins and have a similar diameter. It therefore made sense to test the structure of the spider's organ for its suitability in the fight against biofilms. Here, too, the project was a success: the use of this structure led to a reduction in adhering bacteria of up to 90 percent, without the need for resistance-inducing biocides.

A network of business and science

The Berlin Brandenburg Airport region is characterised by close cooperation between business and science. Here, companies have access to excellent academic and institute-based research as well as an environment in which scientific institutions and technology-oriented companies work together. These optimal conditions create ideal conditions for turning innovative concepts into marketable products.

For further information on the economic development of growth sectors in the region and on business and technology support for companies, investors and scientific institutions, please contact

Melanie Gartzke I melanie.gartzke(at)airport-region.de

Source: Newsletter "Adlershof Journal", article "A non-stick structure - Inspired by the spider's curling iron"(Kai Dürfeld), 07 July 2023