? 日本高清一区二区三

日本高清一区二区三

Dec 24, 2018 | By Cameron

A recent advancement out of Penn State allows for 3D printed porous tissue. One of the biggest hurdles of fabricating living tissue is replicating blood vessels and porous textures. 3D printing is well suited to create those complex structures as multiple materials can be mixed or positioned in specific geometries, even on the inside of an object. Still, even with 3D printing, there remain obstacles, and one of those is size.

Ibrahim Ozbolat, associate professor of Engineering Science and Mechanics at Penn State, explains, "One of the problems with fabrication of tissues is that we can't make them large in size. Cells die if nutrients and oxygen can't get inside." As the science of creating blood vessels is still nascent, most fabricated tissues are kept small enough that researchers can manually deliver nutrients where they’re needed. If a piece of tissue is volumetrically large, it’s difficult to get nutrients to the core of the tissue.

If researchers are working with stem cells, the same issue prevents internal cells from being exposed to the chemical compounds that trigger differentiation into the desired cell type. A porous structure would simulate the job of blood vessels, allowing oxygen, nutrients, and other relevant compounds to circulate throughout the tissue, so the researchers developed a concoction of stem cells from human fat and sodium alginate porogens sourced from seaweed; the sodium alginate forms tiny particles in the tissue that are dissolved after it’s 3D printed, leaving behind small holes or pores in the tissue.

Using this method, strands of 3D printed tissue comprised of undifferentiated cells can be combined to form patches that can then be differentiated into specific cells like the bone and cartilage tested in the study. The porous structure successfully delivered the differentiation-triggering agent to all stem cells and maintained pore connectivity of 85% for three weeks.

The method could improve various medical treatments. "These patches can be implanted in bone or cartilage, depending on which cells they are," said Ozbolat. "They can be used for osteoarthritis, patches for plastic surgery such as the cartilage in the nasal septum, knee restoration and other bone or cartilage defects."

The researchers are now working to apply the technique to other tissue types such as muscle and fat. Years from now, version 5.0 of this technology will be used to heal accident victims as well as the disabled by 3D printing functional muscles that may even outperform their natural counterparts.

 

 

Posted in 3D Printing Application

 

 

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