How do defects affect shapes?

Biological processes can be viewed not only from the classical – genetic or biochemical – perspective. This is analysed by Prof. Łucja Kowalewska from the UW Faculty of Biology and Prof. John W. C. Dunlop from the University of Salzburg – the authors of an article published on 16th April in “Science”. The researchers lead the international European Curvature and Biology Network, which brings together scientists from various disciplines interested in the topic of curvature in nature.

In the classical view, the appearance of tissues in living organisms depends on their genetic “programme” and on the mechanical forces acting on the cells – their growth, division and interactions. Dr Paul Guillamat from the Institute of Bioengineering of Catalonia (IBEC), together with his team, decided to investigate whether the process of tissue formation can not only be observed but also controlled. The researchers conducted an experiment involving the creation of a precise pattern of fibronectin – an extracellular matrix protein – on a soft substrate, with deliberately placed topological defects. Fibroblast cells cultured on this substrate arranged themselves according to the pattern, wrapping around the defect sites and forming an ordered layer that behaved like a liquid crystal.

It turns out that living tissues can be programmed to adopt specific three-dimensional shapes. Depending on the number and arrangement of defects, a flat layer of cells, once detached from its substrate, spontaneously bends into predictable forms, such as cups or saddle-shaped structures. The results of this research may help, amongst other things, to better understand the fundamentals of how complex shapes form in nature, as well as in the development of regenerative medicine and the design of the “smart materials” of the future, which change shape in response to external stimuli.

“It is not only genes or biochemistry that influence biological processes. Geometry and physics, for example, are equally important,” says Prof. Łucja Kowalewska from the UW’s Faculty of Biology, who, together with Prof. John W. C. Dunlop from the University of Salzburg, published her commentary on the research described in the paper entitled ‘Guidance of cellular nematic elastomers into shape-programmable living surfaces’. Both the article and the commentary were published on 16th April in ‘Science’.

 

“Topological defects deliberately introduced into a protein substrate not only alter the shape of the structure, but also act as a kind of ‘controller’, dictating how the cells growing on that surface behave. Often, it is enough to alter the physical conditions, for example by introducing local curvature, to influence the development of a given structure. This shows that, alongside genes, physical and geometric factors also play a significant role in shaping organisms,” explains Prof. Kowalewska.

As the researcher adds, the perspective article she co-authored with Prof. Dunlop was written in connection with the leading roles both authors play in the European Curvature and Biology Network. This is an international research network (currently funded under the COST EuroCurvoBioNet action) that brings together scientists from various disciplines interested in the topic of shapes and curvature in nature. The team comprises biologists, physicists, mathematicians and engineers who work together to investigate the origins of specific organism shapes and how these influence the development of tissues and organs.

Time and biology

You can read about the research of Prof. Łucja Kowalewska – winner of the National Science Centre Award 2025 – in the university’s magazine “UW”: