Abstract: According to the present invention there is provided a method for determining kinetic parameters of a reaction between analyte and ligands, the method comprising the steps of, a) flowing a first volume of sample fluid (V1), which has a concentration (co) of analytes, over a test surface (3) of a flow cell (2) which has first ligands (4) attached thereto, for a first time period (tia); b) flowing a first volume of buffer solution (X/?) over the test surface (3) of the flow cell (2), for a first time period (tib); c) flowing at least a second volume of sample fluid (V2), over the test surface, for a second time period (t2a); wherein the second time period (t2a) is greater than the first time period (tia) and wherein the second volume of sample fluid (V2) has the same concentration (c0) of analytes as the concentration (c0) of analytes in the first volume of sample fluid (V2); d) flowing a second volume of buffer solution (V2?) over the test surface (3) of the flow cell (2), for a second time period (t2b); e) us

Abstract: There is provided an assembly, useable to screen sample fluids for predefined molecules, the comprising, a needle unit comprising n hollow needles, wherein n is greater than one; a flow cell unit comprising m flow cells, wherein m is greater than one, each flow cell having an input and an output, and a test surface on which ligands can be provided; a first selector valve unit which is fluidly connected between the needle unit and flow cell unit, which is operable to selectively fluidly connect any one of the n hollow needles with the m flow cells in the flow cell unit; a pumping means which is selectively operable to provide negative pressure; a second selector valve unit which is fluidly connected between the pumping means and the output of each flow cell. There are further provided methods of screening sample fluids for predefined molecule.

Abstract: According to the present invention there is provided an assembly comprising, a needle unit comprising n hollow needles wherein n is greater than one, and wherein each hollow needle can receive a respective sample fluid; a flow cell unit comprising m flow cells wherein m is greater than one, each flow cell having an input and an output, and a test surface on which ligands can be provided located between the input, and output; a means for consecutively moving sample fluids, from each of said n hollow needles respectively, into all said m flow cells, so that said sample fluids flow consecutively through the same flow cells. There is further provided a corresponding method of screening a sample fluid for molecules which can bind to predefined ligands.

Abstract: Methods for screening a plurality of sample fluids for molecules which can bind to predefined ligands, comprising, selecting one of a plurality of flow cell groups by fluidly connecting the selected flow cell group to a sample delivery unit; injecting a sample fluid to be screened from the sample delivery unit into the flow cells in the selected flow cell group; for each flow cell in the selected flow cell group, recording a signal using a sensor which represents the binding and/or the dissociation of molecules of the sample fluid to/from ligands on the test surface of that flow cell; carrying out a damage assessment step using said recorded signals; if it is determined that the test surface of a flow cell in the selected flow cell group is damaged, then fluidly connecting the other flow cell group to the sample delivery unit. There is further provided assemblies which can be used to implement the afore-mentioned methods.

Abstract: A flow conduit system (100, 200a, 200b) suitable for biochemical sensing, the flow conduit system (100, 200a, 200b) having a first flow cell conduit (1) with one or more sensing areas for biochemical sensing; a first selector valve (4); a first inlet/outlet conduit (2) which fluidly connects the first flow cell conduit (1) to the first selector valve (4); a first injection conduit (6) having a first end and a second end; a second injection conduit (7) having a first end and a second end; a fluid injecting means (8) fluidly connected to the second ends of each of the first and second injection conduits (6, 7) so that the fluid injecting means can selectively inject fluids into the first and/or second injection conduits (6,7); wherein the first injection conduit (6) is fluidly connected, at its first end, to the first inlet/outlet conduit (2) by a valveless junction (9), and the second injection conduits (6) is fluidly connected, at its first end, to the first inlet/outlet conduit (2) by a valveless junction (9