Selective adsorption of an antibody onto a plasma-polymerized film for protein patterning

Techniques for patterned modification of substrate sur faces are important for forming microarrays on protein chips. A hexam-ethyldisiloxane plasma-polymerized film (HMDS PPF) was deposited on a glass substrate and the resulting surface was partially modified by sub sequent nitrogen plasma treatment with a patterned shadow mask. When surface adsorption of an antibody protein (F(ab')₂ fragment of anti-human immunoglobulin G) was visualized by fluorescence microscopy, distinct 80 x 80 μm² square spots were observed, surrounded by a non-fluorescent 80 μmi-wide grid. This pattern could be attributed to proteins selectively ad sorbed onto the nitrogen plasma-treated regions but not onto the surface of pristine HMDS PPF. This provided a simple fabrication method of protein patterning.