Lasers Facilitate Neuron Regeneration

Intricate scaffolds, with features 1000 times smaller than a millimeter, have been created using an ultrafast titanium sapphire laser. These scaffolds can effectively harness the growth of neuronal cells and can be used as delivery vehicles to drop cells off at damaged locations to help treat diseases such as Alzheimer’s and Parkinson’s.

The repairing of neural tissue — for example peripheral nerves, the spinal cord and brain — has long been investigated using tissue engineering, a technique in which tissues and organs are formed by growing cells onto materials outside of the body. Tissue engineering relies heavily on the creation of scaffolds that determine the efficiency, size, shape and orientation of cell growth.

By fine-tuning the makeup and design of these scaffolds, one can use them as a delivery vehicle to drop cells off at a specific damaged location and to help them attach and grow. The scaffolds then degrade in the body without damaging the cells or host.

In this study, the researchers, from the University of Crete and the University of Sheffield, fabricated a scaffold from a commonly used polymer calledpolylactic acid (PLA). This synthetic, biocompatible material degrades in the human body to form lactic acid, a naturally occurring chemical that can easily be removed, leaving the regenerated tissue behind in the required size, shape and structure.

The titanium sapphire laser was tightly focused on the PLA material and moved through three dimensions to create complicated submicrometer structures. Within the structures, small struts and holes were fabricated to ensure stability and the efficient delivery of nutrients to the cells; both are essential for tissue generation.

Taking the fabrication one step further, 3-D seashell structures were created from the polymer to demonstrate the intricacy of the laser technique.

To test the compatibility of the structures, the researchers grew neuronal cells on them and observed, using high-power microscopes, how the cells proliferated and aligned.

The neuronal cells showed good compatibility with the PLA structures with less than 10 percent of the cells dying after five days.

“This is the first time we have been able to structure polylactide with such high resolution and the first time that direct laser writing has been applied to tissue engineering,” said Frederik Claeyssens, professor at the University of Sheffield. “Compared to other techniques, direct laser writing allows the scaffold to be created in a user-defined manner on the micrometer level and provides the possibility to explore the relationship between structure of, and cell growth on, the scaffold.”

The study was published in IOP Publishing's journal Biofabrication.

For more information, visit: www.uoc.gr or www.shef.ac.uk