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  • investin3d investin3d Jan 22, 2013 5:17 PM Flag

    University of Toronto have invented an inexpensive 3D tissue printer

    Tissue engineering has taken a big leap forward: researchers at the University of Toronto have invented an inexpensive 3D tissue printer that makes layered, substantial patches of engineered tissue — tissue that could be used as grafts for burn victims or vascular patches.

    (Credit: University of Toronto)

    "There's a lot of interest in soft materials, particularly biomaterials," says Associate Professor Axel Guenther of the Department of Mechanical and Industrial Engineering, "but until now no one has demonstrated a simple and scalable one-step process to go from microns to centimeters."

    (Lian Leng, 29, demonstrates how the extrusion system collects and produces hydrogel sheets. Credit: JENNIFER ROBERTS)

    Graduate students Lian Leng, Boyang Zhang, and Arianna McAllister contributed to the invention in the labs of Axel Guenther and Associate Prof. Milica Radisic, core professor at IBBME and the Department of Chemical Engineering and Applied Chemistry. They have invented a new printing device that may allow for the uniform, large-scale engineering of tissue.

    How does a 3D printer print a large patch of living tissue?

    Leng, a PhD student in microfluidics and the lead on the project, explains that the core of the 3D printer is a small, unassuming-looking rubber device with seven tiny wells.

    Researchers manipulate biomaterials into these seven channels. The biomaterials are then mixed, causing a chemical reaction that forms a "mosaic hydrogel"- a sheet-like substance compatible with the growth of cells into living tissues, into which different types of cells can be seeded in very precise and controlled placements.

    Unlike the "scaffolding" method of tissue creation, where a structure is created and then cells planted onto it afterward, cells planted onto the mosaic hydrogel sheets are precisely incorporated into the mosaic hydrogel sheet just at the time it's being created. This dramatically increases the precision of the cell placement.

    For showing how precise placement of the cells can be, scientists spell words "Toronto" (shown below) to prove they can precisely mimic the natural placement of cells in living tissues.

    By collecting these sheets around a drum, the machine is able to collect layers of cells in thicknesses made to measure: in essence, three dimensional, functional tissues. The resulting tissues are remarkably stable, says Lian Leng. "In this case, when we put the cells in the right places we create cellular organization quite naturally."

    "The cells are able to stretch and connect with each other, which is very important for ultimately obtaining functional tissues," Guenther states.

    If we are successful, we could significantly decrease length of [hospital] stay," Burn surgeon Marc Jeschke says, "and length of stay is associated with the risk of infections, sepsis, organ failure and so forth. There would be a profound decrease in costs as well. There are also a lot of patients that need help in Third World countries, that don't have money for the care we have now." The fabricated skin will look much better than a graft, he says, increasing its value to patient quality of life.

    The device is not only faster and more precise than other tissue printers, it's also much cheaper. Guenther says the prototype printer cost a few hundred dollars to make. One early version of the receiving chamber was a fish tank purchased in Chinatown.

    The hope is to have a trial with five to 10 human patients within two to three years. The University of Toronto has filed two patents of the invention and plan to commercialize it to sell to other research institutes and hospitals.

    The research findings appear in the journal Advanced Materials.

    Source: Theglobalandmail & utoranto


    Posted in 3D Printing Technologoy

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