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Researchers at University of California San Diego School of Medicine and Institute of Engineering in Medicine have used rapid 3-D printing technologies to create a spinal cord, then successfully implanted that scaffolding, loaded with neural stem cells, into sites of severe spinal cord injury in rats.
The implants are intended to promote nerve growth across spinal cord injuries, restoring connections and lost function. In rat models, the scaffolds supported tissue regrowth, stem cell survival and expansion of neural stem cell axons out of the scaffolding and into the host spinal cord.
“In recent years and papers, we’ve progressively moved closer to the goal of abundant, long-distance regeneration of injured axons in spinal cord injury, which is fundamental to any true restoration of physical function,” said co-senior author Mark Tuszynski, MD, Ph.D., professor of neuroscience and director of the Translational Neuroscience Institute at UC San Diego School of Medicine. Axons are the long, threadlike extensions on nerve cells that reach out to connect to other cells.
“The new work puts us even closer to real thing,” added co-first author Kobi Koffler, Ph.D., assistant project scientist in Tuszynski’s lab, “because the 3-D scaffolding recapitulates the slender, bundled arrays of axons in the spinal cord. It helps organize regenerating axons to replicate the anatomy of the pre-injured spinal cord.”
Co-senior author Shaochen Chen, Ph.D., professor of nanoengineering and a faculty member in the Institute of Engineering in Medicine at UC San Diego, and colleagues used rapid 3-D printing technology to create a scaffold that mimics central nervous system structures. “Like a bridge, it aligns regenerating axons from one end of the spinal cord injury to the other. Axons by themselves can diffuse and regrow in any direction, but the scaffold keeps axons in order, guiding them to grow in the right direction to complete the spinal cord connection,” Chen said.
Faster, More Precise Printing
The implants contain dozens of tiny, 200-micrometer-wide channels (twice the width of a human hair) that guide neural stem cell and axon growth along the length of the spinal cord injury. The printing technology used by Chen’s team produces two-millimeter-sized implants in 1.6 seconds. Traditional nozzle printers take several hours to produce much simpler structures.
The implants contain dozens of tiny, 200-micrometer-wide channels (twice the width of a human hair) that guide neural stem cell and axon growth along the length of the spinal cord injury. The printing technology used by Chen’s team produces two-millimeter-sized implants in 1.6 seconds. Traditional nozzle printers take several hours to produce much simpler structures.