3D printing of soft lithography mold for rapid production of polydimethylsiloxane-based microfluidic devices for cell stimulation with concentration gradients

Three-dimensional (3D) printing is advantageous over conventional technologies for the fabrication of sophisticated structures such as 3D micro-channels for future applications in tissue engineering and drug screening. We aimed to apply this technology to cell-based assays using polydimethylsiloxane (PDMS), the most commonly used material for fabrication of micro-channels used for cell culture experiments. Useful properties of PDMS include biocompatibility, gas permeability and transparency. We developed a simple and robust protocol to generate PDMS-based devices using a soft lithography mold produced by 3D printing. 3D chemical gradients were then generated to stimulate cells confined to a micro-channel. We demonstrate that concentration gradients of growth factors, important regulators of cell/tissue functions in vivo , influence the survival and growth of human embryonic stem cells. Thus, this approach for generation of 3D concentration gradients could have strong implications for tissue engineering and drug screening.