December 10, 2015

New understanding of how shape and form develop in nature

Morphogenesis Credit: University of Cambridge

(December 10, 2015)  Researchers have identified a new mechanism that drives the development of form and structure, through the observation of artificial materials that shape-shift through a wide variety of forms which are as complex as those seen in nature.

Researchers have developed a new method for generating complex shapes, and have found that the development of form in nature can be driven by the physical properties of materials themselves, in contrast with earlier findings. The results, reported in the journal Nature, could enable the construction of complex structures from simple components, with potential applications in pharmaceuticals, paints, cosmetics and household products such as shampoo.

Using a simple set-up – essentially droplets of oil in a soapy water solution which were slowly frozen – the researchers found that recently-discovered ‘plastic crystal’ phases formed on the inside surfaces of the droplets causes them to shape-shift into a wide variety of forms, from octahedrons and hexagons to triangles and fibres.

Previous efforts to create such complex shapes and structures have used top-down processing methods, which allow a high degree of control, but are not efficient in terms of the amount of material used or the expensive equipment necessary to make the shapes. The new method, developed by researchers from the University of Cambridge and Sofia University in Bulgaria, uses a highly efficient, extremely simple bottom-up approach to create complex shapes.

“There are many ways that non-biological things take shape,” said Dr Stoyan Smoukov from Cambridge’s Department of Materials Science & Metallurgy, who led the research. “But the question is what drives the process and how to control it – and what are the links between the process in the biological and the non-biological world?”

Smoukov’s research proposes a possible answer to the question of what drives this process, called morphogenesis. In animals, morphogenesis controls the distribution of cells during embryonic development, and can also be seen in mature animals, such as in a growing tumour.

In the 1950s, the codebreaker and mathematician Alan Turing proposed that morphogenesis is driven by reaction-diffusion, in which local chemical reactions cause a substance to spread through a space. More recent research, from Smoukov’s group and others, has proposed that it is physical properties of materials that control the process. This possibility had been anticipated by Turing, but it was impossible to determine using the computers of the time.

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