A medical device (1) for repairing an injury to the spinal cord (2) or peripheral nerve comprises a first biocompatible or biological flexible substrate (10), which supports first nanoparticles of silicon or carbon or gold or titanium, at least partially embedded in a binding layer (20) made of binding material. The binding layer (20) is joined to the first flexible substrate (10) and each first nanoparticle develops along a predominant direction of development (X). The nanoparticles are oriented in such a way that, statistically, the preferential direction of development (X) is substantially parallel to a first orientation of growth (XI)· Stem cells are at least partially embedded in the binding layer (20). The first nanoparticles are functionalized in such a way that the differentiation of such stem cells along the first nanoparticles is guided in the first orientation of growth (XI)； The first flexible substrate (10) is suitable to assume a distended configuration (A) and a wrapped configuration (B). In the wrapped configuration (B), the first flexible substrate (10) is wrapped around the spinal cord (2) or peripheral nerve whereby said first orientation of growth (XI) is substantially statistically parallel to the neuronal direction (Χ') of extension of the neurons of the spinal cord or the peripheral nerve.Un dispositif médical (1) pour réparer une lésion au niveau de la moelle épinière (2) ou du nerf périphérique comprend un premier substrat souple biocompatible ou biologique (10), qui supporte des premières nanoparticules de silicium ou de carbone ou d'or ou de titane, au moins partiellement incorporées dans une couche de liaison (20) constituée d'un matériau de liaison. La couche de liaison (20) est reliée au premier substrat souple (10) et chaque première nanoparticule se développe le long d'une direction de développement prédominante (X). Les nanoparticules sont orientées de telle sorte que, statistiquement, la direction préférentielle de développement (X)
