**3.2 Softlithography**

In softlithography, the reverse master is designed and fabricated in such a way as to have protruding patterns on its surface. It can be the positive or negative image of a target LoC. Silicon, PMMA, or a chemical-coated PDMS can be made to bear the master image. One of the benefits of softlithography is that it can be used to fabricate LoCs with three-dimensional microfluidics channels and also to form microstructures, including channels, and submacrostructures, including cell-culture chambers [29, 30, 35]. Softlithography technique is convenient, straightforward to apply, accessible to a wide range of users, and low-cost nonphotolithographicbased approach for micro and nanofabrication. Some softlithography techniques are: microcontact printing (μCP), microtransfer molding (μTM), replica molding (REM), micromolding in capillaries (MIMIC), and solvent-assisted micromolding (SAMIM). **Table 3** compares the advantages and disadvantages of conventional photolithography and softlithography [29].
