Fig. 4.

Characterization of the 3D microfluidic high throughput drug screening device with 5 µM of fluorescein and buffer at the inlets of device at a flow rate of 20 µl h⁻¹. The relationship between the normalized fluorescent intensity and the channel number shows that intensity increases with increasing channel number implying that the concentration gradient generator of the device (CGG) produces linear concentrations of fluorescein in the device.