Versatile stamps in microcontact printing: transferring inks by molecular recognition and from ink reservoirs

Microcontact printing is a heavily used surface modification method in materials and life science applications. This concept article focuses on the development of versatile stamps for microcontact printing that can be used to bind and release inks through molecular recognition or through an ink reservoir, the latter being used for the transfer of heavy inks, such as biomolecules and particles. Conceptually, such stamp properties can be introduced at the stamp surface or by changing the bulk stamp material; both lines of research will be reviewed here. Examples include supramolecular stamps with affinity properties, polymer-layer-grafted PDMS stamps, and porous multilayer-grafted PDMS stamps for the first case, and hydrogel stamps and porous stamps made by phase-separation micromolding for the second. Potential directions for future advancement of this field are also discussed.