Solid, liquid or gas?

When an organism grows, its feeling also changes

Now, MIT researchers have discovered that the arrangement of tissue cells can be used as a fingerprint of the "stage" of the organization

The team hopes that what they call "configuration fingerprinting" can help scientists track physical changes during embryonic development

In cancer, there is already evidence that, like an embryo, the physical state of the tumor may indicate its stage of growth

Researchers at the Massachusetts Institute of Technology are analyzing images of tumors growing in the laboratory and patient biopsies to identify cellular fingerprints to indicate whether the tumor is more like a solid, liquid or gas

Ming Guo, associate professor of mechanical engineering at the Massachusetts Institute of Technology, said: "Our method can easily diagnose the cancer status by checking the location of the cells in the biopsy

Order of triangles

In a perfect solid, the components of the material are arranged into an ordered lattice, just like the atoms in a cube

Guo uses this structure as a template for a perfect solid structure.

"True organizations are never perfect and orderly," Guo said

Based on this idea, the research team started with images of various tissues and used software to draw triangular connections between tissue cells

For each triangle in the image, they measured two key parameters: the volume order, which is the space within the triangle; and the cut order, or the distance between the triangle and the equilateral

"We directly calculate the exact values ​​of these two parameters and compare them with the parameters of a perfect solid, and then use these exact values ​​as our fingerprints," Guo explained

Steam tendril

The team tested its new fingerprint technology in several different scenarios

"People know what happens in this very simple system, and this is what we see," Guo said

The researchers then applied their method to cells rather than molecular systems

"As a flow, this may help growth," Guo said

He and his team also cultivated small tumors from cells of human breast tissue and observed that the tumors grew tendrils similar to appendages—a sign of early metastasis
.
When they mapped the structure of tumor cells, they found that non-invasive tumors resemble something between solid and liquid, invasive tumors are more like gas, and tendrils show a more disordered state
.

"Invasive tumors are more like water vapor, they want to spread anywhere," Guo said
.
"Liquids can hardly be compressed
.
But gases are compressible.
They expand and contract easily.
This is what we see here
.
"

The team is studying samples from human cancer biopsies, and they are imaging and analyzing these samples to hone their cellular fingerprints
.
Ultimately, Guo envisions mapping the stages of a tissue as a quick and less invasive method for diagnosing many types of cancer
.

"Doctors usually have to perform a biopsy and then stain different markers based on the type of cancer to make a diagnosis," Guo said
.
"Maybe one day, we can use optical tools to observe the location of the cells without touching the patient, and directly tell the patient what stage the cancer is at
.
"