(162ar) Incorporation of Peptoid Microsphere and Polyelectrolyte Multilayered Depositions for Guided Neural Stem Cell Differentiation.

The creation of novel materials that replicate the body’s natural environment can lead to more effective treatments in combatting brain damage caused by strokes and neurodegenerative diseases. The implantation of healthy neuronal cells is a key strategy in restoring brain function, but researchers wish to create better surfaces that further increase cell viability and control stem cell differentiation to specific neuronal cell types. The neural network is composed of neurons and astrocytes that rely on each other for optimal communication. The extracellular matrix plays a significant role in neural stem cell fate through its’ topography and biochemical composition. Research has shown that the topography and spatial arrangement of features on artificial extracellular matrix surfaces can directly guide stem cell differentiation to desired ratios of neurons and astrocytes. In this work, we have created peptoid microsphere surfaces that can be tuned to form desired contact angles with the surface. These varying contact angles and topographical features from the peptoid microspheres increase stem cell adhesion and guide differentiation. Preliminary studies show that culturing human embryonic stem cells on the peptoid microsphere surfaces results in excellent cellular viability and directed differentiation into primarily adult neuronal cells. We have also developed nanometer-thick layers of naturally occurring polymers such as heparin, collagen, and poly-L-lysine on top of our peptoid microspheres via layer-by-layer synthesis methods. Our results have shown that adding 3 bilayers of heparin and collagen layers forms thin enough films to completely cover the microspheres, while still maintaining the microsphere surface topography. These surfaces ultimately gives us the topographical keys to differentiate neural stem cells into desired ratios of neurons and astrocytes that maximize neuronal network functionality.