A team of Stanford researchers has been studying the qualities of collagen, a protein in the human body that both cushions and protects living tissue by altering its fluidity and elasticity. A Stanford News article published yesterday detailed the findings of the researchers and also likened collagen to Silly Putty through its unique characteristics, which could enable collagen to usher in a variety of developments in regenerative medical research.
Ovijit Chaudhuri, assistant professor of mechanical engineering and associate member of the Stanford Cancer Institute, told Stanford News that collagen proteins are “exquisitely sensitive to mechanical cues,” as well as chemical cues. Beyond responding to chemicals and hormones produced by the human body, collagen is receptive to physical changes around it — and can adjust both its stiffness and its function accordingly.
Chaudhuri said that, among other advancements, collagen could be used to reach a better understanding of breast cancer and how to measure its progression.
“It has been found that enhanced tissue stiffness promotes breast cancer progression and that altered stiffness can even cue stem cells to differentiate in certain ways,” Chaudhuri said.
Chaudhuri worked on the study with Sungmin Nam, a graduate student also studying mechanical engineering. Nam described the structure of collagen biopolymers as “cross-linked,” resembling the mesh of a fishing net, which explains the key finding from the team’s research: A greater application of physical force on collagen will make it stiffer, but it will also hasten the collagen’s return to a semi-fluid state after the force dissipates.
“These cross-links, however, are not always particularly strong, and can be quite weak,” Nam said. “In other words, the greater the force on the cross-links, the quicker they unbind. So the more force on the collagen in general, the quicker you’ll see a subsequent relaxation.”
With this in mind, collagen may prove very useful in bioengineering tissue. Through strategic deformation of collagen, it could be manipulated to grow into particular shapes and fill in gaps where tissue had been surgically removed. By balancing collagen’s attributes of elasticity and viscosity, it could become a versatile tool with further research.
“As we gain insights into cell-collagen interaction, it could help us develop new techniques for 3D cell culture and tissue regeneration,” Nam said.
Both Chaudhuri and Nam highlighted the importance of the interactions between collagen and its surrounding “microenvironment.”
“We’re learning that the mechanics of the microenvironment, mediated through the physical forces cells exert on the microenvironment, play major roles in cell function,” Chaudhuri said.
Nam agreed, adding that collagen in turn “affect[s] these microenvironments through strain-stiffening and viscoelasticity.”
Chaudhuri and Nam were joined in the research by Manish J. Butte, assistant professor of pediatrics at the Stanford School of Medicine, and Kenneth H. Hu, a graduate student in biophysics.
Contact Jacob Nierenberg at jhn2017 ‘at’ stanford.edu.