Fluid Dynamics And Tissue Movement

 Imagine watching a video showing two streams of droplets of ink in an ink jet printer and realizing that one of the streams was not a video, it was a simulation.  A young researcher realized that it was possible to predict everything about ink droplets.

The simulation was based on the laws of fluid dynamics which explains how gases and liquids behave. This one event, lead to a young researcher and his team to publishing a paper concluding that sheets of epithelial tissues, those tissues that make up skin and sheathe internal organs act as liquid crystals.

Liquid crystals are materials whose structure is ordered like a crystal but flows like a liquid.  It was discovered there are two different symmetries within the epithelial tissues.  These symmetries determine how liquid crystals react to physical forces but each appears at different scales.

This discovery could make it much easier to apply fluid dynamic based simulations to living tissues. it is hoped people can use this information to predict how tissues react in various situations ranging from healing to cancer metastasizing. 

We know that liquid crystals flow like liquids but they have a certain structure but their reaction to stimuli  tends to be based on symmetry and orientation.  Most people see this when they watch a liquid crystal display.  The crystals refract light based on their orientation.  In addition to being found in televisions, liquid crystals are found in cells and cell membranes.  Scientists hit a wall because they found that small groups of crystals had a six fold hexatic symmetry while tissues had a two fold nematic symmetry which created a contradiction.

Eventually one scientists said this was possible if both symmetries existed in the same time based on simulations. With the help of a biologist, they were able to see how both symmetries existed but they needed a real situation to distinguish the two symmetries in the tissue.  They created a shape tensor which captured information about cell shapes and their and directions of cells in a tissue sample. In very small clusters, they saw that the cells had a sloped hexagonal shape but in larger clusters of cells the two fold symmetry emerged confirming the earlier model.

Although they were able to prove the simulation, they still aren't sure how the change from six fold to two fold symmetry happens or what signals the change. it is theorized that there is either a cell that causes the change or due to the way the cells adhere to each other.  However, scientists have also suggested that this occurrence helps cells be more than their whole.

With this confirmation, scientists have a direction to move in their research.  Let me now what you think, I'd love to hear.  Have a great day.