Hydrodynamic Assembly of Astrocyte Cells in Conductive Hollow Microfibers

The manufacturing of 3D cell scaffoldings provides advantages for modeling diseases and injuries as it enables the creation of physiologically relevant platforms. A triple-flow microfluidic device is developed to rapidly fabricate alginate/graphene hollow microfibers based on the gelation of alginate induced with CaCl2. This five-channel microdevice actualizes continuous mild fabrication of hollow fibers under an optimized flow rate ratio of 300:200:100 mu L min-1. The polymer solution is 2.5% alginate in 0.1% graphene and a 30% polyethylene glycol solution is used as the sheath and core solutions. The biocompatibility of these conductive microfibers by encapsulating mouse astrocyte cells (C8D1A) within the scaffolds is investigated. The cells can successfully survive both the manufacturing process and prolonged encapsulation for up to 8 days, where there is between 18-53% of live cells on both the alginate microfibers and alginate/graphene microfibers. These unique 3D hollow scaffolds can significantly enhance the available surface area for nutrient transport to the cells. In addition, these conductive hollow scaffolds illustrate unique advantages such as 0.728 cm3 gr-1 porosity and two times more electrical conductivity in comparison to alginate scaffolds. The results confirm the potential of these scaffolds as a microenvironment that supports cell growth. Astrocytes are encapsulated in alginate/graphene hollow microfibers. The electrochemical properties of the composite microfibers and the long-term viability of astrocytes encapsulated in these microstructures are evaluated. Graphene is used to increase the conductivity of microfibers for applications such as intracellular recording and stimulation of neuronal cells.image