Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Collagen nanofibrils in mammalian tissues get stronger with exercise

14.12.2018

Collagen is the fundamental building block of muscles, tissues, tendons, and ligaments in mammals. It is also widely used in reconstructive and cosmetic surgery. Although scientists have a good understanding about how it behaves at the tissue-level, some key mechanical properties of collagen at the nanoscale still remain elusive. A recent experimental study conducted by researchers at the University of Illinois at Urbana-Champaign, Washington University, and Columbia University on nanoscale collagen fibrils reported on, previously unforeseen, reasons why collagen is such a resilient material.

Because one collagen fibril is about one millionth in size of the cross-section of a human hair, studying it requires equally small equipment. The group in the Department of Aerospace Engineering at U of I designed tiny devices--Micro-Electro-Mechanical Systems--smaller than one millimeter in size, to test the collagen fibrils.


A collagen fibril mounted on a MEMS mechanical testing device. At the bottom is a single human hair for size comparison.

Credit: University of Illinois Department of Aerospace Engineering


Left to right front: Julia Liu and Debashish Das. Back: Ioannis Chasiotis and Fan Yang.

Credit: University of Illinois at Urbana-Champaign Department of Aerospace Engineering

"Using MEMS-type devices to grip the collagen fibrils under a high magnification optical microscope, we stretched individual fibrils to learn how they deform and the point at which they break," said Debashish Das, a postdoctoral scholar at Illinois who worked on the project. "We also repeatedly stretched and released the fibrils to measure their elastic and inelastic properties and how they respond to repeated loading."

Das explained, "Unlike a rubber band, if you stretch human or animal tissue and then release it, the tissue doesn't spring back to its original shape immediately. Some of the energy expended in pulling it is dissipated and lost. Our tissues are good at dissipating energy-when pulled and pushed, they dissipate a lot of energy without failing.

This behavior has been known and understood at the tissue-level and attributed to either nanofibrillar sliding or to the gel-like hydrophilic substance between collagen fibrils. The individual collagen fibrils were not considered as major contributors to the overall viscoelastic behavior. But now we have shown that dissipative tissue mechanisms are active even at the scale of a single collagen fibril."

A very interesting and unexpected finding of the study is that collagen fibrils can become stronger and tougher when they are repeatedly stretched and let to relax.

"If we repeatedly stretch and relax a common engineering structure, it is more likely to become weaker due to fatigue," said U of I Professor Ioannis Chasiotis. "While our body tissues don't experience anywhere near the amount of stress we applied to individual collagen fibrils in our lab experiments, we found that after crossing a threshold strain in our cyclic loading experiments, there was a clear increase in fibril strength, by as much as 70 percent."

Das said the collagen fibrils themselves contribute significantly to the energy dissipation and toughness observed in tissues.

"What we found is that individual collagen fibrils are highly dissipative biopolymer structures. From this study, we now know that our body dissipates energy at all levels, down to the smallest building blocks. And properties such as strength and toughness are not static, they can increase as the collagen fibrils are exercised," Das said.

What's the next step? Das said with this new understanding of the properties of single collagen fibrils, scientists may be able to design better dissipative synthetic biopolymer networks for wound healing and tissue growth, for example, which would be both biocompatible and biodegradable.

###

The study "Energy dissipation in mammalian collagen fibrils: Cyclic strain-induced damping, toughening, and strengthening," was co-authored by Julia Liu, Debashish Das, Fan Yang, Andrea G. Schwartz, Guy M. Genin, Stavros Thomopoulos, and Ioannis Chasiotis. It is published in Acta Biomaterialia.

The research was supported by the National Science Foundation and National Institutes of Health and by the National Science Foundation Science and Technology Center for Engineering MechanoBiology. Das' effort was supported by a grant from the National Science Foundation.

Ioannis Chasiotis | EurekAlert!
Further information:
https://aerospace.illinois.edu/news/collagen-nanofibrils-mammalian-tissues-get-stronger-exercise
http://dx.doi.org/10.1016/j.actbio.2018.09.027

More articles from Health and Medicine:

nachricht The cytoskeleton of neurons has been found to be involved in Alzheimer's disease
18.01.2019 | University of the Basque Country

nachricht Bioinspired nanoscale drug delivery method developed by WSU, PNNL researchers
10.01.2019 | Washington State University

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Ten-year anniversary of the Neumayer Station III

The scientific and political community alike stress the importance of German Antarctic research

Joint Press Release from the BMBF and AWI

The Antarctic is a frigid continent south of the Antarctic Circle, where researchers are the only inhabitants. Despite the hostile conditions, here the Alfred...

Im Focus: Ultra ultrasound to transform new tech

World first experiments on sensor that may revolutionise everything from medical devices to unmanned vehicles

The new sensor - capable of detecting vibrations of living cells - may revolutionise everything from medical devices to unmanned vehicles.

Im Focus: Flying Optical Cats for Quantum Communication

Dead and alive at the same time? Researchers at the Max Planck Institute of Quantum Optics have implemented Erwin Schrödinger’s paradoxical gedanken experiment employing an entangled atom-light state.

In 1935 Erwin Schrödinger formulated a thought experiment designed to capture the paradoxical nature of quantum physics. The crucial element of this gedanken...

Im Focus: Nanocellulose for novel implants: Ears from the 3D-printer

Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing.

It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains:

Im Focus: Elucidating the Atomic Mechanism of Superlubricity

The phenomenon of so-called superlubricity is known, but so far the explanation at the atomic level has been missing: for example, how does extremely low friction occur in bearings? Researchers from the Fraunhofer Institutes IWM and IWS jointly deciphered a universal mechanism of superlubricity for certain diamond-like carbon layers in combination with organic lubricants. Based on this knowledge, it is now possible to formulate design rules for supra lubricating layer-lubricant combinations. The results are presented in an article in Nature Communications, volume 10.

One of the most important prerequisites for sustainable and environmentally friendly mobility is minimizing friction. Research and industry have been dedicated...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Our digital society in 2040

16.01.2019 | Event News

11th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Aachen, 3-4 April 2019

14.01.2019 | Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

 
Latest News

Additive manufacturing reflects fundamental metallurgical principles to create materials

18.01.2019 | Materials Sciences

How molecules teeter in a laser field

18.01.2019 | Life Sciences

The cytoskeleton of neurons has been found to be involved in Alzheimer's disease

18.01.2019 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>