Highly localized, selective deprotection chemistry and efficient grafting reactions in microcontacts between elastomeric stamps and reactive polystyrene-block-poly(tert-butyl acrylate) (PS690-b-PtBA(1210)) diblock copolymer films are developed. The procedure yields well-defined protein-poly(ethylene glycol) (PEG) nanopatterns (see figure), which may find applications in, for example, cancer-cell-surface interaction studies.