Microcontact printing (µCP) is a soft lithography technique used for functionalizing a surface by micropatterning. This technique is particularly attractive for biological applications as it offers the ability to pattern substrates with complex molecules relevant to biology. For example, one can pattern a substrate with "cell-friendly" proteins to promote the adhesion of cells.

Poly(dimethyl siloxane) (PDMS) is the most commonly used polymer for fabrication of the elastomeric stamp (commercial product: Sylgard 184 from Dow Corning). Typically, PDMS is casted from a reusable silicon master

obtained by deep reactive ion etching. The elastomeric stamp is "inked" with a thin layer of proteins that is transferred to the bio-MEMS device by μCP. Conformal printing is the key for successful μCP.

In our laboratory, we have developed a mechanical system for alignment of the elastomeric stamp with the bio-MEMS device. With a resolution of a few micrometers, this system is appropriate for the micropatterning of protein layers having feature sizes of several tens of micrometers. The setup enables the application of a well-controlled even pressure during the µCP process.