. 2 Microfabrication Techniques for Production of Organ-on-a-Chip Systems -Using hydrogel microtechnology to create "plug and play" systems that mimic the functions of human organs -Using lithograph

. • Soft Lithography: Soft Lithography is a carving out of patterns on a substrate through micro-molding in order to create microfluidic networks. This technique has the advantage of being relatively inexpensive, as well as the ability to be tailored towards specific organ-on-a-chip systems. The limitation of this technique is that it is limited to very specific geometries, as well as being limited in terms of the size of the channels that can be created. • Photolithography: Photolithography is a patterning technique whereby a photoresist layer is exposed to certain wavelengths of light, selectively removing the photoresist to create channels of a specific size. This technique has the advantage of having the ability to be tailored towards different organ-on-a-chip systems, as well as having the capability of creating more complex and intricate channel designs. The limitation of this technique is that it is more expensive than Soft Lithography, as well as having a steeper learning curve.