Use of PDMS as a glue at the interface could also be an option for providing a strong bonding force 129 . In this case, a thin layer of uncured or semi-cured PDMS is introduced on the surface of one or both of the bonding layers and after bringing the layers into contact, the platform is heated up to fully solidify the PDMS at the interface thereby fastening the layers to each other. Although PDMS glue and adhesive tapes can provide relatively high bonding strength, the resolution and accuracy of the microchannels are not as good as the other methods. Moreover, regarding the uncured or semi-cured PDMS, the leakage of PDMS into the channel and consequently changing the channel geometry or clogging the channel is a common problem. In addition, PDMS shrinks as the device cools down, resulting in misalignment of the channels. Reprinted from Ref. with permission from Springer.