Development and Validation of a Long-Term 3D Glioblastoma Cell Culture in Alginate Microfibers as a Novel Bio-Mimicking Model System for Preclinical Drug Testing

Background: Various three-dimensional (3D) glioblastoma cell culture models have a limited duration of viability. Our aim was to develop a long-term 3D glioblastoma model, which is necessary for reliable drug response studies. Methods: Human U87 glioblastoma cells were cultured in alginate microfibers for 28 days. Cell growth, viability, morphology, and aggregation in 3D culture were monitored by fluorescent and confocal microscopy upon calcein-AM/propidium iodide (CAM/PI) staining every seven days. The glioblastoma 3D model was validated using temozolomide (TMZ) treatments 3 days in a row with a recovery period. Cell viability by MTT and resistance-related gene expression (MGMT and ABCB1) by qPCR were assessed after 28 days. The same TMZ treatment schedule was applied in 2D U87 cell culture for comparison purposes. Results: Within a long-term 3D model system in alginate fibers, U87 cells remained viable for up to 28 days. On day 7, cells formed visible aggregates oriented to the microfiber periphery. TMZ treatment reduced cell growth but increased drug resistance-related gene expression. The latter effect was more pronounced in 3D compared to 2D cell culture. Conclusion: Herein, we described a long-term glioblastoma 3D model system that could be particularly helpful for drug testing and treatment optimization.

Behavior of Neural Cells Post Manufacturing and After Prolonged Encapsulation within Conductive Graphene-Laden Alginate Microfibers

Engineering conductive 3D cell scaffoldings offer unique advantages towards the creation of physiologically relevant platforms with integrated real-time sensing capabilities. Toward this goal, rat dopaminergic neural cells were encapsulated into graphene-laden alginate microfibers using a microfluidic fiber fabrication approach, which is unmatched for creating continuous, highly tunable microfibers. Incorporating graphene increases the conductivity of the alginate microfibers 148%, creating a similar conductivity to native brain tissue. Graphene leads to an increase in the cross-sectional sizes and porosities of the fibers, while reducing the roughness of the fiber surface. The cell encapsulation procedure has an efficiency rate of 50%, and of those cells, approximately 30% remain for the entire 6-day observation period. To understand how encapsulation effects cell genetics, the genes IL-1β, TH, TNF-α, and TUBB-3 are analyzed, both after manufacturing and after encapsulation for six days. The manufacturing process and combination with alginate leads to an upregulation of TH, and the introduction of graphene further increases its levels; however, the inverse trend is true of TUBB-3. Long-term encapsulation shows continued upregulation of TH and of TNF-α, and six-day exposure to graphene leads to the upregulation of TUBB-3 and IL-1β, which indicates increased inflammation.

Polymorphic calcium alginate microfibers assembled using a programmable microfluidic field for cell regulation

A single microfluidic chip was used to control a complex fluid field to prepare polymorphic microfibers for cell regulation.