Rapid prototyping of PDMS microdevices via µPLAT on nonplanar surfaces with flexible hollow-out mask.

A major goal of PDMS microfabrication is to develop a simple and inexpensive method for rapid fabrication. Despite the recent advancements in this field, facile PDMS microfabrication on non-planar surfaces remains elusive. Here we report a facile method for rapid prototyping of PDMS microdevices via µPLAT (microscale plasma-activated templating) on non-planar surfaces through micropatterning of hydrophilic/hydrophobic interface by flexible PVC hollow-out mask. This mask can be easily prepared with flexible PVC film through a cutting crafter and applied as pattern definer during the plasma treatment for microscale hydrophilic/hydrophobic interface formation on different substrates. The whole process requires low inputs in terms of time as well as toxic chemicals. Inspired by liquid molding, we demonstrated its use for rapid prototyping of PDMS microstructures. Following the proof-of-concept study, we also demonstrated the use of the flexible hollow-out mask to facilitate cell patterning on curved substrates, which is difficult to realize with conventional methods. Collectively, our work utilizes flexible and foldable PVC film as mask materials for facile microscale hydrophilic non-planar surface modification to establish a useful tool for PDMS prototyping and cell patterning.