A microfluidic device for generation of chemical gradients

A microfluidic device was developed for generating chemical concentration gradients by integrating PEG-diacrylate (PEGDA) hydrogel separators in a Polydimethylsiloxane (PDMS) chamber. In this device, the linear chemical gradient in the central culture channel is achieved by the diffusion of two side flow streams which are separated by hydrogel separators. Two long serpentine channels feed into a transition zone to balance the pressure of both streams insuring a stable gradient is formed and maintained before it reaches the central culture channel. This device provides a reproducible, controllable, long-term steady and linear chemical concentration gradient without complex supports. Additionally, the concentration gradient can be controlled by varying the hydrogel thickness, thereby changing the amount of diffusion through the hydrogels. This device can be modified to create different chemical gradients for a variety of cell culture applications.