CONVERGENCE – where material science meets biological folding

When two diverse sciences converse, they either widen their divide or unearth some gems of syncretism. Physicists at the University of Syracuse have discovered correlations between the material forces of glass making and embryonic morphogenesis. In an interview in Quanta magazine, associate professor of physics, Lisa Manning discusses this phenomenon. Manning and her colleagues were intrigued by the phase transitions of glass formation, those moments when the fluid (molten) state of glass shifts to a solid state. The team noted the possible relationship between the actions of physical forces during this fluid-to-solid phase transitionand the processes of embryonic development – how cellular flow evolves into functional bodily form.

 

Throughout these blogs on human origami, I have been repeatedly (and delightfully) baffled by how a human embryo creates a body without a brain. What conditions in the embryo’s movement-matrix dynamics give rise to (induce) the ability to orchestrate a human body? How do all the tissues and organs find their proper place? How do these cells know just where to go to create complex systems? For the Syracuse team, it seems mechanical forces of glass making provide insight into how a fluid mass of cells can self-organize into solid organ form.

 

Glass making itself is a mysterious art-science that dates back to the 16th century BC. Witnessing these smithy-artists today blowing a scalding glob of liquid sand into a crystal vase, is motion to behold.

 

 

By studying models of glass formation, the researchers began to better understand these fluid-to-solid phase transitions – and by association, how the embryo might transition from a streaming mass of migrating cells into solid bodily forms. In the life of the embryo, these mechanical forces are key in helping change matter from dynamic, itself, into a solid functioning organ.

 

Manning explains one clue to the mystery: convergence.The word confluence is an elegant term in science which suggests a coming together or merging. Metaphorically, convergence is a confluent conversationbetween two cellular surfaces – a seeking, touching and converging of two cells, sealing them together. In embryogenesis, convergence is where space-time relations tighten and congeal through mechanical forces. Millions of cells form streaming patterns that migrate madly, congealing as they arrive at their destination. Thesharpness of these cellular interfaces depends on surface tension and the stickiness of the cellular adhesive, Manning explains.  As fluid forces come together, a lack of gaps or overlaps between cells can result. As cells migrate towards one another and become more tightly packed and ‘confluent’ a single cell becomes a tissue, an organ, a system. Given contemporary emphasis of chemical and genetic processes in human development, Manning’s findings help resurrect the importance of mechanical forces within biological growth and development (see Quanta reference for more explanation).

 

What does this research have to do with folding? Folding is the product of mechanical forces…and much more. Human bodily folding throughout embryonic development is a quintessential gesture of biological growth and development. It is a conversation occurring over two-weeks between masses of cells and the fluid matrix of the womb — perhaps the most important dialogue you’ll ever have in your life. Over this time frame, the embryo undergoes a phase shift from masses of cells in the fluid matrix of the womb to a formed body. The cells themselves exhibit self-regulation, an inner drive that meets the human need of finding proper space and place. Both interior and exterior bodily forms arise from folding, enfolding and unfolding.  Cilia also beat and drive the fluid in various directions, turning and twisting tissue that folds on itself until such confluence yields shape– the shape of the entire you.The enfolding initiates the axial midline, a process that continues to deepen the space within the growing embryo and lay out an asymmetrical inner body plan – the heart on one side, the gall bladder on the other. This ‘topological interaction,’ says Manning, plays a large role in how the embryo is able to develop normally (without pathology).

 

My recent foray into IPhone photography has offered me a glimpse into the inter-relationship between folding and phase transitions.                      I’ve become somewhat obsessed with looking at folds in the environment – not only in nature, but also in urban trash, the play of light and shadow, and other phenomena. Just the other day, I wandered into a vacant car lot and came upon a discarded mattress covered with a piece of corrugated cardboard. The folding patterns were unbelievable – again, reminding me of embryogenesis – how folds in a flat sheet shape shifts into a moving landscape of peaks and valleys, a cardboard-made-river, shaped by the confluence of material mechanics and environmental forces.

 

Our biology…an emergent phenomenon of folding that hinges on agency and mechanics. This convergence of cells is a matter of (epi)genetics, but also a confluence of bioelectric energies, agency, art, craft, imagination and mystery.As developmental psychologist Esther Thelen (1941-2004) once said, remarking on the nature of human behavior: ‘Crying lies neither in the organism nor in the environment alone, but only in their confluence.’

 

 

 

References

 

Linda B Smith, Esther Thelen (1996). A DYNAMIC SYSTEMS APPROACH TO THE DEVELOPMENT of COGNITION and ACTION, p. 26.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1540-5834.1991.tb01154.x

 

Jordana Cepelewicz. Tissue Engineers Hack Life’s Code for 3-D Folded Shapes. QUANTA magazine. 6/12/18, 07:26.

https://www.quantamagazine.org/tissue-engineers-hack-lifes-code-for-3-d-folded-shapes-20180125/