Figure 1.

(A) Concept of the cells-on-a-chip module presented in this work. A fibrous matrix is coated inside of a channel network for 3D cell culture. Reagents (media or other solutions) are allowed to flow through the network of cells and matrix, providing continuous nutrient supply and waste removal. (B) Experimental setup of electrospinning directly into an assembled device with the aid of dynamic fiber focusing. A polymer solution is pushed by a syringe pump through a steel cannula (i.d.=300 μm, o.d.=550 μm), which is connected to a 25 kV voltage supply. The electric field force generates a Taylor cone at the end of the cannula, which then undergoes Rayleigh instability and eventual fiber formation. Without being focused, the fibers whip over a large area and thus cannot be confined into a channel device. An air sheath device was designed and fabricated in this work, which can be placed around the cannula. When air flow is introduced to the sheath from the side port, the air pressure surrounding the Taylor cone dynamically focused the fibers into the channel, with the extra fibers coming out of the other end of the device.