Laminin-Functionalized Gelatin Microgels for the Generation of Functional Neurons from Neural Progenitor Cells

The development of suitable hydrogels as delivery vehicles for neural stem/progenitor cells (NSPCs) is ongoing. Most injectable hydrogels for NSPC delivery either are mechanically fragile or do not promote the desired cell morphological changes during neural differentiation or cell-cell interactions during mature synapse formation. In this report, the utility of a gelatin microgel-based injectable hydrogel is explored for the encapsulation of NSPCs with the purpose of generating functional neurons. In addition, we describe facile enzymatic chemistry for the conjugation of bioactive proteins, such as laminin, to the surface of gelatin microgels to improve cell adhesion and organization of encapsulated cells. Encapsulation in the microgel assembly with immobilized laminin substantially improved NSPC viability compared with the nonporous hydrogel with the same chemical composition and resulted in enhanced neural differentiation (both neuronal and glial) with physiologically relevant morphological changes and cell-cell connections evidenced by immunofluorescence imaging. The firing of functional neurons when stimulated by glutamate was confirmed by calcium flux imaging after 4 weeks of differentiation. These results indicate the potential usage of gelatin microgels as an injectable formulation for NSPC delivery for neural tissue regeneration.