Neurothreads: Cryogel carrier-based differentiation and delivery of mature neurons in the treatment of Parkinson's disease

We present in-vivo transplantation of mature dopaminergic neurons by means of macroporous, injectable carriers, to enhance cell therapy in Parkinsons disease. The carriers are synthesized by crosslinking carboxymethylcellulose at subzero temperatures, resulting in cylindrical, highly resilient porous cryogels, which we term Neurothreads. We develop efficient covalent immobilization of the neural adhesion proteins laminin 111, collagen IV and fibronectin, as well as of the extracellular matrix extract Matrigel to the Neurothreads. We observe the highest neural spreading on laminin 111 and Matrigel. We show compatibility with established dopaminergic differentiation of both HS420 human embryonic stem cells and the LUHMES midbrain model cell line. The porous Neurothread carriers withstand compression during minimally invasive stereotactic injection, and ensure viability of mature neurons including extended neurites. Implanted into the striatum in mice, the Neurothreads enable survival of transplanted mature neurons obtained by directed differentiation of the HS420 human embryonic stem cells, as a dense tissue in situ, including dopaminergic cells. With the successful in-vivo transfer of intact, mature and fully open 3D neural networks, we provide a powerful tool to extend established differentiation protocols to higher maturity and to enhance preconfigured neural network transplantation.