Abstract: The invention relates to a device for exposing a substrate surface to at least one fluid. The device comprises a substrate having a surface containing a contiguous target region and a cover plate. A plurality of fluid-transporting features is present in a cover plate surface, and the features are separated by at least one partitioning wall representing an integral portion of the cover plate. The features fluidly communicate with at least one outlet, and each feature fluidly communicates with an inlet. The cover plate surface is positioned in fluid-tight contact with the substrate surface such that the at least one partitioning wall contacts the contiguous target region. As a result, each feature, in combination with the substrate surface, forms a flow passage containing a distinct exposure zone on the target region. Also provided are methods for exposing a substrate surface to a plurality of cells and methods for detecting cell-cell interactions.

Abstract: The invention relates to methods and devices for forming a concentration gradient of a reagent for use in chemotactic evaluation. A flow passage is provided and defined at least in part by a substrate having a target region on a surface thereof. A concentration gradient of a reagent is formed over the target region by controlled delivery of a fluid containing the reagent in laminar flow through the flow passage and over the target region. The concentration gradient is suitable for chemotactic evaluation. Typically, the inventive methods and devices are employed to evaluate the chemotactic interaction between a candidate compound and a monolayer of immobilized cells.

Abstract: The invention pertains to devices and methods relating to the formation of one or more fluid lanes on a substrate surface, to expose a portion of a target region on the surface to one or more reagents. Typically, a flow passage is provided that is defined at least in part by a substrate having a target region on a surface thereof. One or more inlets each allows a fluid to be introduced in contiguous laminar flow through the flow passage to form a fluid lane downstream from the inlet over a portion of the target region. Typically, at least one inlet is position to allow a fluid to be introduced directly into the flow passage in a direction nonparallel to the flow passage. Typically, the inventive devices and methods may be employed to determine the effects of a plurality of candidate compounds on a monolayer of immobilized cells.

Abstract: A flow cell assembly is provided comprising a first plate member and a second plate member, which may be built into an analysis station, each having a respective first surface. Said first and second plate members overlie one another with their respective first surfaces facing one another. A cavity defined between said first surfaces and a plurality of channels in said second plate member each lead to a respective portion of said cavity from a further surface of the second plate member. The cavity provides an analysis field on said first plate member. There are at least three inlet flow channels and at least one outlet flow channel all communicating with the analysis field for providing hydrodynamically positioned flow over said field. Methods for using the novel systems in analyte screening and for selectively exposing a cell to analyte are provided as well.

Abstract: The present invention relates to an enzyme sensor for measuring the concentration or activity of an analyte in a test fluid. The sensor has at least one enzyme layer comprising an immobilized enzyme for which the analyte is a substrate. The immobilized enzyme is obtained by formation of one or more covalent link(s), optionally by using a cross-linking agent, between the enzyme and at least one type of macromolecule in the presence of a competitive inhibitor for said enzyme. The present invention also relates to a membrane for an enzyme sensor. Furthermore, the invention relates to a method for stabilizing the enzymatic activity of an enzyme sensor.

Abstract: A frame plate (11) for a plate heat exchanger has two ports (12, 13), to which there are connected two tubes provided with annular flanges (16, 17). The ports (12, 13) are situated so close to each other that there is no room for the flanges (16, 17) of the two tubes to be arranged side by side. The problem is solved, according to the invention, by arranging at least one port (12), between the frame plate (11) and the annular tube flange (16), at least one removable spacing member (14) surrounding a communication channel between the port (12) and the interior of the tube, the tube flange (16), further, being connected with the frame plate (11) by means (18) separate from the spacing member (14) in a manner such that the latter is clamped between the frame plate (11) and the tube flange (16).