Patent ID: 7105356

Claim:
A method of analyzing a fluid sample for at least one analyte, comprising the steps of: providing a flow cell having a sensing surface; providing a laminar flow of a first sensitizing fluid and a laminar flow of a second fluid adjacent to the flow of the first sensitizing fluid such that the two laminar fluids flow together over the sensing surface with an interface to each other; adjusting the relative flow rates of the first sensitizing fluid and the second fluid to position the interface such that the first sensitizing fluid contacts a discrete sensing area of the sensing surface for selective sensitization thereof to generate a sensitized sensing area; providing a laminar flow of a second sensitizing fluid and a laminar flow of a third fluid adjacent to the flow of the second sensitizing fluid such that the two laminar fluids flow together over the sensing surface transversely to the direction of the first sensitizing fluid with an interface to each other; adjusting the relative flow rates of the second sensitizing fluid and the third fluid to position the interface such that the second sensitizing fluid overlaps with the sensing area sensitized by the first sensitizing fluid for selective re-sensitization of the overlapping area by the second sensitizing fluid to generate an overlapping sensitized sensing area sequentially sensitized by the first and second sensitizing fluids; contacting at least the overlapping sensitized sensing area with the fluid sample; and detecting interaction between the at least one analyte of the fluid sample and the overlapping sensitized sensing area.