Properties Of Layer-by-layer Single-cell Encapsulation And The Potential Applications In Transplantation Therapy For Neurologic Disorders

In this project, we first report the encapsulation of single neural stem cells(NSCs) using a layer-by-layer(Lb L) self-assembly technique with polyelectrolytes gelatin and alginate. Viability, proliferation and differentiation of encapsulated NSCs did not change dramatically. When insulin-like growth factor-1(IGF-1) was loaded on the coating material alginate, its release from alginate into the medium presented in a time-dependent and p H-dependent way. IGF-1 significantly enhanced the proliferation of the encapsulated NSCs, demonstrating a drug-carrier function of the Lb L single-cell nanocoating. At the condition of p H 6.5, NSCs in IGF-1-loaded LbL group displayed better survival rate.Permeability of Lb L encapsulation was also performed on PC12 cells by applying gelatin and hyaluronic acid(HA). Under certain conditions, permeability of Lb L structure against FITC-dextran(FD) increased with the molecular weight of FD decreased. Higher concentration of materials and thicker layers would yield decreased permeability to certain FD. In addition, maintaining the physiological pH was also important to keep the Lb L encapsulation system stable. Furthermore, 0.5% of materials for 8-layer encapsulation was proved to greatly inhibit the interation of tumor necrosis factor-α(TNF-α) with its receptor in the first 3 days and roboustly alleviated cell death led by TNF-α.In short, since the encapsulation structure created artificial microenvironment for cells and was able to enhance the cellular functions or endow protection, it would be viewed as a potential treatment strategy for neurologic disorders such as stroke, spinal cord injury etc., in which the disturbed microenvironment resulted in the low survival and disfunction of grafted cells.