Implant printed on a bioprinter returns mobility to paralyzed mice

A team of scientists from the University of California at San Diego reported on a new achievement in the field of three-dimensional bioprinting. For the first time in history, they managed to print an implant imitating a fragment of the spine. After its installation and engraftment, the rodent regained control over previously paralyzed hind limbs.

The difficulty with creating implants for the spinal cord is that it is necessary to connect among themselves axons, extremely thin nerve fibers that are sensitive to different conditions. Neither traditional 3D printing materials nor printers are suitable here. The size of a single drop of a substance is about 200 microns, while axons lie in channels that are much thinner, so the implant cannot be printed in the usual way, layer by layer.

Scientists have applied the technology of continuous projection microprinting, based on the material polyethylene glycol-gelatin methacrylate. This hydrogel hardens under the influence of ultraviolet radiation, but it happens very quickly, so the liquid polymer was mixed in advance with live neural stem cells. Light is irradiated over the entire plane of the material according to the product scheme embedded in the printer, 1000 times faster than conventional 3D printing, after which the output is a solid object with cells embedded in it. It took only 1.6 seconds to print the implant 2 mm thick.

After installation in the rat's spine, the implant lasted 4 weeks, and on the 5th it began to degrade - as planned. During this time, the axons managed to grow through the channels in the implant and create a stable connection. Now within a few months, the implant framework will gradually decompose, and living tissue will take its place. If everything goes according to plan, then after clinical trials, after about 5 years, experiments will begin on the printing of complex parts of the human body.

techcult.ru