A new method for the generation of patterned protein films by encapsulation in arrays of thermally evaporated lipids

In this article we demonstrate a versatile method for the generation of pat terned protein films by encapsulation in arrays of the lipids, octadecylami ne (ODA, cationic), and arachidic acid (AA, anionic). A simple 2 x 2 array of ODA and AA was vacuum deposited on different substrates using appropriat e masks. Thereafter, the enzymes pepsin and fungal protease as well as the heme-proteins cytochrome c and hemoglobin were encapsulated in the differen t elements of the array by sequential immersion (combined with judicious ma sking) of the array elements in the different protein solutions. The protei ns are incorporated into the lipid elements by electrostatic interaction be tween charged amino acid residues on the protein surface and charged functi onal groups in the lipid matrix. This procedure leads to spatially distinct regions of the different proteins on one substrate and shows promise for s ingle-chip multianalyte immunoassay/multiplex, high-throughput biosensor an d catalysis applications. Fourier transform infrared spectroscopy (FTIR) wa s used to monitor the incorporation of the proteins in the different elemen ts of the array as well as to ascertain whether intermixing of the proteins in a particular array element had occurred. The heme-protein composite reg ions were further characterized using UV-VIS spectroscopy. (C) 2001 John Wi ley & Sons, Inc.