The high cost and harsh processing conditions associated with microfabricated biosensors demand a new approach to receptor immobilization. We have grafted biotin labeled, 3400 molecular weight poly(ethylene glycol) (PEG) to silicon surfaces to produce a dense PEG monolayer with functionally active biotin. These surfaces have been activated with antibodies through the strong streptavidin-biotin interaction by simply incubating the surfaces with antibody-streptavidin conjugates. The stability of the biotinylated PEG monolayers produces a sensing element that can be regenerated by removal of the streptavidin conjugate and stored in a dry state for extended periods of time.