3D-printed implant promotes spinal cord injury repair
A 3D-printed micro-mesh implant has been developed to promote neural regeneration after spinal cord injury.
Researchers at the Royal College of Surgeons in Ireland University of Medicine and Health Sciences (Dublin) have developed a 3D printed implant that delivers targeted electrical stimulation to damaged areas of the spinal cord. This approach mimics the structure of the human spinal cord, possessing the ability to conduct electrical impulses to neurons and stem cells, enhancing their ability to grow and regenerate. The findings from the study offer a promising new approach to spinal cord and nerve damage repair.
Spinal cord injury-induced neurotrauma causes chronic pain, sensation loss and paralysis, with no effective treatments due to pathophysiological challenges like inflammation, scarring and limited neuronal regrowth. Electrical stimulation has shown promise for neural regeneration, activating circuits and promoting axonal regrowth; however, current methods often target limited neuron subsets, reducing the effectiveness of electrical stimulation for other neuron subsets. Additionally, other factors that pose as a potential approach in electrical stimulation healing, such as the use of metallic electrodes, commonly used for electrical stimulation, face issues like stiffness, poor neurocompatibility and toxic ion release, making them unsuitable for neural scaffolds.
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Ian Woods, first author and Research Fellow at the Tissue Engineering Research Group at the Royal College of Surgeons in Ireland, and his team hypothesized that integrating MXene nanosheets, an ultra-thin nanomaterial, into a tissue engineering scaffold could enhance electroactive signalling for neural regeneration. Previous studies have demonstrated the promising applications of MXene nanosheets for neural applications due to their high conductivity, stability and biocompatibility with various neural cell types, including neurons, astrocytes and microglia. Based on this, they used a specific type of MXene nanosheet, Ti3C2Tx, to create their implant.
Before they carried out their study, they measured the electroconductive properties of the Ti3C2Tx MXene substrates and tested their biocompatibility with neurons, astrocytes and microglia. Next, they used a high-resolution 3D printing technique, melt electrowriting, to produce biocompatible micro-meshes of varying microfiber densities to allow spatial control of the scaffold’s electroconductive properties. MXene nanosheets were added to the micro-meshes to make them electroconductive.
Following this, they embedded the MXene micro-meshes into an extracellular matrix-based scaffold made of hyaluronic acid, collagen-IV and fibronectin – materials known to support nerve growth and repair in spinal cord injuries. This MXene-extracellular matrix scaffold provided a soft, gel-like structure to support axonal growth. This design of the micro-mesh mimics the spinal cord in structure and softness, where the micro-mesh fibers were arranged like the nerve bundles in the spinal cord and could carry electrical signals like the spinal cord.
The researchers then assessed the scaffold’s effect in a multicellular model, where nerve cell clusters (murine olfactory bulb-derived neurospheres consisting of neurons and stem cells) were grown on high-density MXene micro-meshes. The neurospheres were exposed to electrical stimulation for seven days and upon observation, results showed enhanced axonal growth and neuronal differentiation on the high-density MXene micro-meshes compared to scaffolds without MXene.
The researchers demonstrated that their 3D-printed MXene-based implant effectively delivered electrical signals to neurospheres, encouraging axonal growth and neuronal differentiation to support neural repair and regeneration.
“These 3D-printed materials allow us to tune the delivery of electrical stimulation to control regrowth and may enable a new generation of medical devices for traumatic spinal cord injuries,” commented Woods.
Additionally, the researchers have hope for further application of their technology, with Woods stating that, “beyond spinal repair, this technology also has potential for applications in cardiac, orthopedic and neurological treatments where electrical signaling can drive healing.”