Photolithographic patterning of proteins with photoresists processable under biocompatible conditions

The microlithographic patterning of proteins on solid substrates using photoresists, which can be processed in the presence of biomolecules without affecting their bioactivity, is reported. Chemically amplified resist materials based on poly(t-butyl acrylate) and a newly synthesized copolymer of t-butyl methacrylate, 2-hydroxyethyl methacrylate, isobornyl methacrylate, and acrylic acid designed for this application, are evaluated regarding capabilities for processing under biocompatible conditions (processing temperatures at about 50 degreesC or lower and development with dilute aqueous base developers). The photoresist formulations based on the newly synthesized (meth)acrylate copolymer had higher sensitivity and contrast allowing lithographic processing even without postexposure bake. Patterns down to 3.75 mum lines/spaces of two different protein molecules, rabbit Immunoglobulin G and bovine serum albumin, on aminosilane-treated silicon surfaces, were obtained with a photoresist formulation based on the new copolymer and an onium salt photoacid generator under biocompatible processing conditions. (C) 2001 American Vacuum Society.