New Era In Injury Treatment: 3D Implant Promises To Regenerate The Spinal Cord

Scientists are developing a new type of material that could aid recovery from brain and spinal cord injuries. This material conducts electricity and mimics the natural environment of the nervous system. When used in conjunction with electrical stimulation, it helps neurons grow and reconnect, which could improve regeneration after neurological trauma. This technique could become a new way to treat damage that currently has no cure.

Neurotrauma is a type of injury to the brain or spinal cord that can cause serious problems such as loss of movement, cognitive difficulties (such as memory and attention), and even paralysis. These injuries are very difficult to treat because the central nervous system (the brain and spinal cord) has a limited capacity for regeneration.

This is due to a complex biological process involving inflammation, scar formation, and failure of nerve growth after injury. Therefore, many scientists believe that an effective solution must address the problem from several angles simultaneously, a "multifaceted" approach.

One of the most promising strategies for treating this type of injury is the use of biomaterials, materials designed to interact with the human body and that can help "guide" the regeneration of damaged nerves.

These biomaterials can act as physical bridges between the injured parts and, at the same time, serve as support for therapies such as electrical stimulation. Therapeutic electrical stimulation (ES) acts as a "push" that activates damaged neurons, helping to reconnect broken circuits or even stimulate the growth of new nerve extensions (called axons).

Previous research has shown that this type of stimulation, when applied with electrodes to the skin or directly to the spinal cord, can help reactivate damaged areas of the nervous system. Furthermore, laboratory tests have shown that applying electrical current directly to axons can increase the brain's ability to adapt (plasticity) and improve its function.

It has also been observed that stimulation activates important pathways within the cell, such as the mTOR pathway, which is directly linked to neuron growth.

However, for this stimulation to work effectively, the material used as a "bridge" must be electrically conductive, meaning it must allow the electrical current to pass through it in a controlled and efficient manner.

Furthermore, it must be biocompatible (it cannot cause rejection or inflammation) and have a structure similar to the natural tissues of the nervous system.

Metal electrodes, while used successfully in treatments such as deep brain stimulation (for Parkinson's, for example), are very rigid and can cause damage to sensitive nervous tissue. They can also release toxic substances and do not integrate well with the brain or spinal cord environment.

Therefore, researchers have been developing more modern materials, such as conductive polymers and nanometric composites, mixtures of materials at a microscopic scale. One of the most promising is MXene, a type of nanosheet made of a material called Ti₃C₂Tx, which combines high electrical conductivity, stability, and good interaction with nervous system cells.

These MXenes can be incorporated into structures made of extremely fine fibers (like a mesh) using 3D printing techniques called fusion electrowriting, which allows precise control of the shape, spacing, and density of these fibers.

In this study, researchers at the Royal College of Surgeons in Ireland created an experimental structure with three parts: (1) PCL fibers (a biocompatible polymer), (2) a coating of MXene nanosheets to conduct electricity, and (3) a gelatinous matrix mimicking the natural substance that surrounds brain cells, made with hyaluronic acid, collagen, and fibronectin, all natural components found in the human body. This "mixture" resulted in a soft, conductive environment ideal for neuron growth.

This study analyzed whether a new type of material, made with a combination of MXene (a conductive nanomaterial) and PCL (a polymer used in medicine), is safe and effective for growing brain cells. Scientists cultivated three types of brain cells, neurons, astrocytes, and microglia, on surfaces made of either PCL alone or the MXene/PCL blend and compared their behavior. The images show that neurons grew better and were more active on surfaces with MXene, which bodes well for spinal cord injury treatments. Astrocytes, which help protect and nourish neurons, also fared well, but with less inflammatory activation on surfaces with MXene, this is positive, as it prevents overreactions in the brain. Microglia, which act as the brain's "immune defense," did not become more active or toxic upon contact with MXene, indicating that the material does not cause dangerous inflammation. Overall, tests showed that the material is non-toxic, supports neuron growth well, and does not stimulate unwanted inflammation, making it very promising for use in implants to regenerate nervous system tissue.

When scientists applied electrical current to these structures with cultured neurons, they observed greater growth of nerve extensions (neurites), and this growth was more intense when the mesh had a higher density of conducting fibers.

In tests with "neurospheres" (small spherical structures composed of various types of mouse brain cells), it was seen that neurons grew more, differentiated better, and formed more complex connections when stimulated by electricity in these dense MXene structures.

Neurons grew and formed more connections when MXene-ECM and electrical stimulation were used.

In summary, the results show that it is possible to combine advanced conductive materials with natural biological structures to create an efficient electrical stimulation platform.

This technology may offer new hope in the treatment of brain and spinal cord injuries by helping to rewire damaged nerve circuits more safely and effectively than traditional methods. This is an important step toward regenerative therapies for the central nervous system, which currently lack truly effective options.

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3D-Printing of Electroconductive MXene-Based Micro-Meshes in a Biomimetic Hyaluronic Acid-Based Scaffold Directs and Enhances Electrical Stimulation for Neural Repair Applications

Ian Woods, Dahnan Spurling, Sandra Sunil, Anne Marie O'Callaghan, Jack Maughan, Javier Gutierrez-Gonzalez, Tara K. McGuire, Liam Leahy, Adrian Dervan, Valeria Nicolosi, and Fergal J. O'Brien 

Advanced Science, e03454, 15 July 2025 

https://doi.org/10.1002/advs.202503454

Abstract: 

No effective treatments are currently available for central nervous system neurotrauma although recent advances in electrical stimulation suggest some promise in neural tissue repair. It is hypothesized that structured integration of an electroconductive biomaterial into a tissue engineering scaffold can enhance electroactive signaling for neural regeneration. Electroconductive 2D Ti3C2Tx MXene nanosheets are synthesized from MAX-phase powder, demonstrating excellent biocompatibility with neurons, astrocytes and microglia. To achieve spatially-controlled distribution of these MXenes, melt-electrowriting is used to 3D-print highly-organized PCL micro-meshes with varying fiber spacings (low-, medium-, and high-density), which are functionalized with MXenes to provide highly-tunable electroconductive properties (0.081 ± 0.053-18.87 ± 2.94 S/m). Embedding these electroconductive micro-meshes within a neurotrophic, immunomodulatory hyaluronic acid-based extracellular matrix (ECM) produced a soft, growth-supportive MXene-ECM composite scaffold. Electrical stimulation of neurons seeded on these scaffolds promoted neurite outgrowth, influenced by fiber spacing in the micro-mesh. In a multicellular model of cell behavior, neurospheres stimulated for 7 days on high-density MXene-ECM scaffolds exhibited significantly increased axonal extension and neuronal differentiation, compared to low-density scaffolds and MXene-free controls. The results demonstrate that spatial-organization of electroconductive materials in a neurotrophic scaffold can enhance repair-critical responses to electrical stimulation and that these biomimetic MXene-ECM scaffolds offer a promising new approach to neurotrauma repair.