Enzyme-assisted nanolithography.

We have chemically immobilized alkaline phosphatase molecules onto the apex of a tip of an atomic force microscope. When the substrate BCIP is dephosphorylated by alkaline phosphatase, it will precipitate in the presence of NBT. By bringing the tip in the vicinity of a suitable sample, we could locally deposit this complex on the sample. Thus we combined the activity of an enzyme with the accuracy in positioning a tip in scanning probe microscopy to demonstrate a novel technique referred to as enzyme-assisted nanolithography. By use of other enzymes, this method will open the possibility to chemically modify surfaces on a nanometer scale.