Gallium Nitride Is Non-toxic And Biocompatible
Recent findings have shown that GaN could be used to construct electrodes used in neurostimulation therapies for Alzheimer’s to transistors used to monitor blood chemistry.
Researchers from North Carolina State University and Purdue University have shown that the GaN is non-toxic and is compatible with human cells – opening the door to the material’s use in a variety of biomedical implant technologies.
GaN is currently used in a host of technologies, from LED lighting to optic sensors, but it is not in widespread use in biomedical implants. However, the new findings mean that GaN holds promise for an array of implantable technologies – from electrodes used in neurostimulation therapies for Alzheimer’s to transistors used to monitor blood chemistry.
Scanning electron microscope image of cell growth on GaN that has been coated with peptides
“The first finding is that GaN, unlike other semiconductor materials that have been considered for biomedical implants, is not toxic. That minimises risk to both the environment and to patients," says Albena Ivanisevic, an associate professor of materials science and engineering at NC State and associate professor of the joint biomedical engineering program at NC State and the University of North Carolina at Chapel Hill.
Researchers used a mass spectrometry technique to see how much gallium is released from GaN when the material is exposed to various environments that mimic conditions in the human body. This is important because gallium oxides are toxic. But the researchers found that GaN is very stable in these environments – releasing such a tiny amount of gallium that it is non-toxic.
The researchers also wanted to determine GaN’s potential biocompatibility. To do this they bonded peptides – the building blocks that make up proteins – to the GaN material. The scientists then placed peptide-coated GaN and uncoated GaN into cell cultures to see how the material and the cells interacted.
They found that the peptide-coated GaN bonded more effectively with the cells. Specifically, more cells bonded to the material and those cells spread over a larger area.
“This matters because we want materials that give us some control over cell behaviour," Ivanisevic says. “For example, being able to make cells adhere to a material or to avoid it.
“One problem facing many biomedical implants, such as sensors, is that they can become coated with biological material in the body. We’ve shown that we can coat GaN with peptides that attract and bond with cells. That suggests that we may also be able to coat GaN with peptides that would help prevent cell growth – and keep the implant ‘clean.’ Our next step will be to explore the use of such ‘anti-fouling’ peptides with GaN."
Further details of this work are described in the paper, “Gallium Nitride is Biocompatible and Non-Toxic Before and After Functionalization with Peptides," by Jewett et al, which will be published in a forthcoming edition of Acta Biomaterialia.
The research was funded by the National Science Foundation.