New hydrogel for neuroglial cell housing

Hydrogels specifically suited for housing central nervous system (CNS) cells represent a weak minority within literature available on gels as tissue engineering scaffolds. This is due to difficulties in building hydrogels allowing CNS cells to survive within them. We aimed at developing a resorbable injectable hydrogel as a suitable cell housing vector for regenerative approaches, particularly to be used with neuroglial cells in injured spinal cord rewiring. New polymeric formulation was studied for hydrogel synthesis together with new protocols for building three-dimensional cell/hydrogel biohybrid constructs. Formulations are based on two different pharmaceutical-grade polymers (a synthetic carbomer and a natural agarose) together with specific crosslinking agents. Gelation procedure allows cells loading directly into construct during gelation (T<40°C), together with specifically tuned media according with cells used. Investigations were performed on N9 microglia and U87 glioma derived cells at a density of 0.5 x 10 6 cells per ml of gel. Hydrogels resulted biocompatible and resorbable: degradation patterns were compatible with cell survival and local tissue housing needs. Injectability was confirmed by tixotropic behaviour. Optical imaging assays showed healthy and spreading cells within gel at various time points; standard living cell counts performed after trypan colouring resulted in about 50% (±10%) of living cells within hydrogel matrix. Our hydrogels are thus among the few that can be used for building 3D constructs for neural cells carrying in reparatory approaches.