Combination of Hyaluronic Acid Hydrogel Scaffold and PLGA Microspheres for Supporting Survival of Neural Stem Cells

Purpose To develop a biomaterial composite for promoting proliferation and migration of neural stem cells (NSCs), as well as angiogenesis on the materials, to rescue central nervous system (CNS) injuries. Methods A delivery system was constructed based on crosslinked hyaluronic acid (HA) hydrogels, containing embedded BDNF and VEGF-loaded poly(lactic-co-glycolic acid) (PLGA) microspheres for controlled delivery and support for NSCs in the CNS. The surface morphologies were evaluated by SEM and AFM, mechanical property was investigated by rheological tests, and release kinetics were performed by ELISA. Bioactivity of released BDNF and VEGF was assessed by neuron and endothelial cell culture, respectively. Compatibility with NSCs was studied by immunofluorescent staining. Results Release kinetics showed the delivery of BDNF and VEGF from PLGA microspheres and HA hydrogel composite were sustainable and stable, releasing similar to 20-30% within 150 h. The bioactivities preserved well to promote survival and growth of the cells. Evaluation of structure and mechanical properties showed the hydrogel composite possessed an elastic scaffold structure. Biocompatibility assay showed NSCs adhered and proliferated well on the hydrogel. Conclusions Our created HA hydrogel/PLGA microsphere systems have a good potential for controlled delivery of varied biofactors and supporting NSCs for brain repair and implantation.