Restorative surgery of the central nervous system by means of tissue engineering using NeuroGel implants

A novel approach aimed at restoring tissue structure and function and enhan cing axonal recovery in damaged parts of the central nervous system is desc ribed. In contrast to contemporary neurotransplantation technologies which focus on tissue reconstruction of neural parenchyma by cell replacement, th is approach is based on repair by tissue engineering. The technique involve s the implantation of a 3-dimensional polymer hydrogel into the site of inj ury. The physical properties of the hydrogel induce the organisation of mig rating wound-healing cells and regenerating axons within its 3-dimensional structure. Two complementary approaches are described and illustrated using results obtained in vivo and in vitro: (1) implantation into the brain and spinal cord of the polymer hydrogel NeuroGel, which has a defined macromol ecular structure that enhances tissue-building capabilities, and the implan tation of advanced hydrogel derivatives carrying biologically active molecu les to promote selective cell interactions, and (2) biohybrid hydrogels tha t contain entrapped developing neural tissue cells, embryonic carcinoma-der ived neurons, or genetically modified cells which secrete neurotrophic fact ors. These techniques create bioartificial tissues with neural tissue speci ficity. The potential of this biomaterial-based approach to neural tissue e ngineering for restorative neurosurgery is discussed.