Bioelectronics offers hope for spinal cord injuries
Bioelectrical scaffolds are implants designed to aid tissue restoration. They hold great potential for the reparation of damaged nervous systems, in part because the chemical and electrical stimuli they provide could facilitate cell regeneration and drive neuronal activity, aiding recovery. This could transform the lives of people who have suffered brain and spinal cord injury, and found their quality of life severely curtailed. “A challenge however is that implants to the brain or spinal cord risk inflicting additional neural injury, leading to inflammation and compromised functionality,” says Neurofibres project coordinator Jorge Collazos-Castro, principal investigator of the Neural Repair and Biomaterials Laboratory at the National Hospital for Paraplegics, Spain. “Besides, the structure of the human nervous system, and the pathology of neurological injuries, are extremely complex. Such problems have frequently been thought of as insurmountable.”
Repairing spinal injuries
Collazos-Castro has dedicated his medical career to advancing the field of neural repair. “Since finishing my doctorate, it has been clear to me that drugs and cellular transplants alone are insufficient alone to restore neural functionality,” he explains. “I recognised the need to further intervene at the lesion site, with an implant that organises the tissue and facilitates neural cell growth. Electroconducting microfibres for example might be able to guide neural cells, while providing chemical and electrical stimulation.” The Neurofibres project built on Collazos-Castro’s previous work in this field. In 2016, he demonstrated how implanted microfibres can guide cell migration with minimal additional injury. However, the regenerative response was limited, and electrical stimulation still not possible. This project worked to overcome these problems. “Our first objective was to ensure that the implant was safe,” notes Collazos-Castro. “We then sought to find ways of increasing neural regeneration through the lesion site.” An implantable, electroconducting scaffold made of protein-modified microfibres was developed. Another objective was to develop affibodies – small molecules with a high affinity towards a specific protein target – to increase functionality.
Engineered tissue reconstruction
The improved carbon microfibres, affibodies, interconnected scaffolds and electrodes were all comprehensively tested in animal models. “We demonstrated that these electrically interconnected scaffolds are suitable for implantation at lesion sites, and are biologically safe,” adds Collazos-Castro. While some beneficial cellular responses were recorded, Collazos-Castro notes that functional recovery in spinal cord injury has not yet been achieved. Additional strategies, including combining electroactive implants with pharmaceuticals, are being explored. “We are confident that this combined approach will succeed in terms of functional neurological restoration,” he remarks. “Our results will enable the integration of existing electronic devices to aid functional recovery after spinal cord injury, and also foster similar approaches to engineer tissue reconstruction in other parts of the body.” The project team is currently working on defining the issues that will require optimisation, in order to move towards clinical applications. “We expect to start testing the safety of the device in humans in the next 5 years, after reconfiguring it for human use and complying with the relevant regulations on electroactive biomedical implants,” says Collazos-Castro. “This will be a costly but highly rewarding long-term enterprise. We are looking for industrial collaborators and investors to make the clinical application of this technology a reality.”
Keywords
Neurofibres, microfibres, scaffolds, implants, neural, brain, spinal, bioelectrical
