Methods and devices are provided for controlling a fluid flow over a sensing surface within a flow cell. The methods employ laminar flow techniques to position a fluid flow over one or more discrete sensing areas on the sensing surface of the flow cell. Such methods permit selective sensitization of the discrete sensing areas, and provide selective contact of the discrete sensing areas with a sample fluid flow. Immobilization of a ligand upon the discrete sensing area, followed by selective contact with an analyte contained within the sample fluid flow, allows analysis by a wide variety of techniques. Sensitized sensing surfaces, and sensor devices and systems are also provided.