Multi-layered 3D-cell culturing chamber (CCC) integrated drug screening platform with linear and logarithmic concentration gradients to screen for anti-cancer drugs

Abstract

Since many microfluidic devices have limited drug dose range and incorporate 2D cell culture, a multi-layered platform with linear and logarithmic gradients and 3D-cell culturing chambers was designed. Hagen-Poiseuille flow resistance equation and the parallel electric schematics were used to derive channel dimensions for the target concentrations. The chip was connected to a syringe pump for continuous infusion of reagents and a waste reservoir. For gradient validation, fluorescein and distilled water were substituted in place of drug and diluting agent. For cell experiments, human bladder cancer cells were embedded in fibrin gels and loaded as 3D-cell cultures. In the single drug experiment, cells were exposed to varying doses of cisplatin with a resulting IC50 value of 7.11 μM. In the combinatorial drug experiment, cells were exposed to varying doses of gemcitabine and a fixed cisplatin dose, which enhanced apoptosis of the bladder cancer cells and confirmed the advantages of combination chemotherapy. Cell viability and cell proliferation rate were quantified, and cell culturing chambers were spaced out 9mm each to be compatible with the standard plate reader. Vertical layout of the chip minimizes the lateral dimension required for housing various components while maintaining a favorable height for imaging. This platform may facilitate implementing microfluidics in combinatory therapy screenings and drug evaluations.