Study the physical properties of cartilage

Cartilage is essential for the movement of the human body, cushioning the bones and joints while maintaining its shape despite the pressure, heavy and irritating activity. Unfortunately, it began to break down after about 60 years, causing conditions such as chronic osteoarthritis and other painful inflammation.

Therefore, Itai Cohen's goal when he ran his lab at Cornell was to clarify the physical properties of cartilage when moving, compressing, twisting and other forms of deformation so that it could be replaced by Artificial cartilage lasts longer and better.

Although Cohen studied biological materials, he was a physicist, not a doctor or a biologist. His main passion lies in the characteristics of complex liquids and concentrated soft materials. In a simpler way, Cohen found it interesting to have sticky things (corn flour, mortar, toothpaste, paint, cells and blood).

Cohen talks about materials that occupy our daily lives and has unique properties with a pervasive enthusiasm.

'This is a daily material that you can see in the kitchen or on the breakfast table. What's interesting behind them is that you have the liquid and solid properties that blend together inside a material. ' Cohen became Cornell's employee under the title of physics assistant in 2005.

The passion for condensed soft materials is the reason Cohen participated in many different projects. In addition to tissue deformation work in his laboratory, he also collaborated with Chekesha Liddell in mechanical and mechanical sciences, with Fernando Escobedo in molecular biology and chemical mechanics in suspension form. glue.

Physical assistant instructor Itai Cohen, on the right, and physics graduate student Mark Buckley examine his tissue deformation device, which is capable of causing pressure and pulling on tissue patterns, for example such as cartilage or eye sclera.(Photo: Lindsay France)

He also delved into three-way collaboration with the faculty in the field of theoretical and applied mechanics, biology and computer biology, studying the evolution of flight ability by observing and calculating models. fly of fruit flies.
Cohen said the general theme of all these projects is how to limit the time and structure of liquids and other complex materials, at different length scales, to change the effects of material type.

Take the cartilage, for example. This is a classic example of a concentrated soft material. It is extremely complex and consists of subtle layering layers, including collagen fibers, proteoglycans - brush-like molecules and electrically charged - and chondrocytes - cell types.

He is trying to discover how all these materials are stacked together to achieve the unique mechanical properties of cartilage, such as the ability to hold shape and strength under the influence of external forces. : pressure, twist or distortion distortion (parallel tension).

Cohen's graduate student Mark Buckley developed a machine called the tissue deformation device that Cohen's team was working on to commercialize in collaboration with Pleasentville, New York-based Harrick Scientific. Using specimens from cows, they put 3 mm cartilage blocks into the machine to push, distort, compress and pull cartilage inside the salt water tank.

Using an attached focal microscope, they can observe and record the three-dimensional structure of cartilage in different lengths and depths, as well as how it responds to stimulation. This machine is not only used to deform cartilage, it also works for tissues like sclera of the eyes, cornea and other hard tissues.

Efforts to understand cartilage can lead to the creation of better artificial joints and deeper scientific knowledge of the ability to tolerate cartilage pressure within the human body.

Chronic osteoarthritis is a mystery to many scientists, but it is clear that cartilage distortion is the most important component in studying this disease.

Cohen said, 'Does this disease start from the surface of the cartilage and enter the bone or start from the bone-cartilage joint and go to the surface - no one knows it yet. No one has ever been able to compare healthy tissue and damaged tissue in the scale that we are working on. '