Improving Neural Progenitor Cell Viability with SingleStem Encapsulation to Enable Higher Rate Injection Delivery

Stem cell transplantation holds therapeutic potential for improving stroke recovery; however, its clinical efficacy is limited by insufficient stem cell survival following injection. This hinders neurotrophic factor release and homing of transplanted stem cells to the injury site. To address these issues, we developed SingleStem, a novel cell encapsulation method that individually coats cells with polyethylene glycol (PEG) biomaterial. Prior work revealed that SingleStem modulates neurotrophic factor release (VEGFA and VEGFB) by altering the extracellular stiffness of neural progenitor cells (NPCs). In this study, we investigated whether SingleStem encapsulation improves NPC viability during higher-rate syringe delivery. We conducted in vitro injection experiments at 1, 2, and 4 µL/min and then assessed the viability of control and SingleStem-modified NPCs. Cell viability was evaluated using Live/Dead staining and fluorescence microscopy. Our results showed that SingleStem modification does not majorly affect cell survival at lower injection rates, such as 1 and 2 μL/min. However, at 4 μL/min, encapsulated NPCs maintained 81% viability and outperformed unmodified NPCs, which had only 47.6% viability (p=0.0016). We conclude that SingleStem encapsulation offers substantial NPC protection during faster delivery, maintaining high stem cell viability. Future work should investigate the maximum viable delivery rate of encapsulated NPCs and the therapeutic potential of SingleStem-modified NPCs in stroke animal models. Altogether, this research seeks to develop more effective stem cell-based stroke therapies.