Micro patterning of active proteins with perforated PDMS sheets (PDMS sieve)

Abstract

We propose a novel technique for patterning active proteins on a glass substrate using a perforated polydimethylsiloxane (PDMS) sheet–sieve. The sieve, which has tapering holes, is fabricated by spin-coating PDMS on a pyramidal-shaped mold. By means of this sieve, FITC (fluorescent isothiocyanate, bovine)–albumin was successfully spotted in a 5 × 5 µm² area in an array. The patterned spots were perfectly isolated, which eliminates the problem of non-specific binding of proteins to undesired areas. To show that proteins maintained their activity after the patterning, we used F₁-ATPase biomolecular motors; their activity can easily be verified by observing their rotary motion after patterning. Selective patterning with three kinds of fluorescent micro beads indicated the possibility of patterning of different proteins on the same substrate by using the sieve.