The intricate structure of mother-of-pearls, also known as nacre, built by multiple single cells has baffled scientists for quite some time now, as they try to understand its formation process. Now, a recent study has shed some light on how these underwater creatures create these remarkably beautiful shells.
Researchers from the B CUBE, Center for Molecular Bioengineering at TU Dresden and European Synchrotron Radiation Facility (ESRF) in Grenoble, published a research in Nature Physics this month. This, for the first time, describes that structural defects in self-assembling nacre attract each other, leading to a perfect periodic structure.
The abstract of the study, titled Dynamics of Topological Defects and Structural Synchronization in a Forming Periodic Tissue, explains that organisms like mollusc form a variety of hierarchically structured extracellular functional tissues. The team of researchers of Maksim Beliaev, Dana Zöllner, Alexandra Pacureanu, Paul Zaslansky, and Igor Zlotnikov used synchrotron-based nano-tomographic imaging along with machine-learning-based segmentation to understand the structural synchronization process of nacre forming in the shell of the mollusca Unio pictorum.
To take a comprehensive look at the internal structure of the early and mature nacre, the researchers from the Zlotnikov group collaborated with the ESRF in Grenoble. According to Nano Werk, Dr Zlotnikov explained that Nacre is an extremely fine structure that has organic features below 50 nanometer in size. Nano technologies like Beamline ID16A at the ESRF provided the team of scientists with an all-new capability to visualize nacre in three-dimensions.
Dr Pacureanu from the X-ray Nanoprobe group at the ESRF said that the combination of electron dense and highly periodic inorganic platelets with delicate and slender organic interfaces makes nacre a challenging structure to image.
Through their study, the team of scientists found that the highly layered structure of nacre is driven by disorder-to-order transition which is achieved through the motion and interaction of screw-like structural dislocations with an opposite topological sign. The team of scientists used an analogy similar to processes observed in liquid-crystalline systems, also known as Kuramoto model, and demonstrated that the microstructural faults in the nacre act as dissipative topological defects coupled by an elastic distortion field surrounding their cores.
Their mutual annihilation results in structural synchronization that is simulated using the classical Kuramoto model. The Kuramoto model was first proposed by Japanese scientists Yoshiki Kuramoto in 1984. The scientist devised a mathematical model to describe synchronization, which is more specifically, a model for the behavior of a large set of coupled oscillators.