Construction And Application Of 3D-printed Neural-like Tissue

Damage on neural system is becoming a severe problem nowadays,causing heavy burden on both families and society.But there is no special curing strategy for it.Stem cell transplantation is the most promising potential therapy for neural system damage.But some problems of stem cell therapy still exist,including teratoma,low cells survival ratio and uncontrollable differentiation.So here I develop a culturing system for neural-like tissue.Combining with 3D print,the neural-like tissue could be used in transplant-repair for neural damage.Hyalurnan?HA?is the most import extracellular matrix for neural system,playing a critical role in brain development and functional stabilization.Molecular weight of HA also influence the role HA plays.So firstly,HA is compared with other material like collagen and gelatin.ALG?alginate?/HA is proved to be the best material for neural stem cells?NSCs?culturing.Then elastic modulus and impedance of the hydrogel is measured when different MW HA is added to the system.I found that the less impedance the system have,the more close its elastic modulus get to brain,the longer neural fibre could enlongate.NSCs reproduce,elongate,form dense neural network,degrade the hydrogel and replace with self-secreted matrix.When culturing up to 8 weeks,the neural-like tissue could be fully developed.Using IF,the cell types of the neural-like tissue is identified.90% of the cell still remain stemness,while just a little differentiate into neuron and glia cell.When putting the tissue into neuron-differentiation-medium,most of the stem cell will differentiate to neuron.This result indicates that the neural-like tissue is plastic.We can determine the cell type inside the tissue.Based on this system,concentration of ALG,HA and CaCl₂ is optimized to fit 3D print.The best combination is 1.5% ALG,0.3%HA and 100 m M CaCl₂.Then single fibre,multi-fibre and several other complicated structure is tested here.The practicability and stability of this system is demonstrated for 3D print.At last,transplantation of the neural-like tissue is done in vivo.And the neural-like tissue transplantation shows much better survival rate of neural cell.After 4 weeks repair,most of the neural-like tissue shows ?III-tubulin positive,which indicate neurons.Besides that,neural-like tissue could form transparent hydrogel-like material in the damaged part.