Method for improving measurement precision in evanescent wave optical biosensor assays
First Claim
1. A method of improving measurement precision in an optical biosensor assay for a ligand in a sample which comprises the steps ofi) incubating the sample in contact with a measurement surface which carries a directly or indirectly immobilised measurement reagent appropriate to the assay and which additionally carries an amount of a directly or indirectly immobilised reference reagent which gives rise to a reference signal, independent of the amount of ligand present in the sample, at the measurement surface, and prior to, during, or subsequent to the said incubation of the sample measuring said reference signal by a method appropriate to the assay;
- ii) simultaneously with or sequentially to the said incubation of the sample in i) introducing one or more labelled ancillary reagents appropriate to the assay whereby if ligand is present in the sample, a complex involving said measurement reagent and at least one of said ligand or said labelled ancillary reagent(s) is formed giving rise to a detectable assay signal which is a first function of the amount of ligand (if any) present in the sample; and
iii) subsequently monitoring the assay signal arising from the measurement surface by a method appropriate to the assay and, comparing the reference signal with the assay signal, thereby determining using an appropriate algorithm whether and/or the extent to which the ligand under assay is present in the sample.
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Abstract
A method for improving measurement precision in an optical biosensor assay for a ligand in a sample is described. The method involves referencing the assay with an artificially raised background level by the labelling of the optical waveguide with an appropriate reference reagent. Devices for use in such a method are also described.
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Citations
19 Claims
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1. A method of improving measurement precision in an optical biosensor assay for a ligand in a sample which comprises the steps of
i) incubating the sample in contact with a measurement surface which carries a directly or indirectly immobilised measurement reagent appropriate to the assay and which additionally carries an amount of a directly or indirectly immobilised reference reagent which gives rise to a reference signal, independent of the amount of ligand present in the sample, at the measurement surface, and prior to, during, or subsequent to the said incubation of the sample measuring said reference signal by a method appropriate to the assay; -
ii) simultaneously with or sequentially to the said incubation of the sample in i) introducing one or more labelled ancillary reagents appropriate to the assay whereby if ligand is present in the sample, a complex involving said measurement reagent and at least one of said ligand or said labelled ancillary reagent(s) is formed giving rise to a detectable assay signal which is a first function of the amount of ligand (if any) present in the sample; and iii) subsequently monitoring the assay signal arising from the measurement surface by a method appropriate to the assay and, comparing the reference signal with the assay signal, thereby determining using an appropriate algorithm whether and/or the extent to which the ligand under assay is present in the sample. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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- 10. A biosensor device comprising a measurement surface carrying a directly or indirectly measurement reagent appropriate to an assay and which additionally carries an amount of a directly or indirectly immobilised reference reagent which gives rise to a reference signal, independent of the amount of ligand present in the sample, at the measurement surface.
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17. A method of manufacturing specifically-reactive sample-collecting and testing devices possessing a cavity or cavities, one surface of each cavity having a zone I carrying a layer comprising, in releasable form, labelled ancillary reagent(s) suitable for the desired assay, said surface being a surface of a first solid plate fashioned of transparent material, wherein the wall of the or each cavity opposite to said first plate comprises a second plate fashioned of transparent material and acts as a light-transmissive waveguide, the second plate having on its surface adjacent the cavity a zone II corresponding in orientation to the aforementioned zone I, zone II carrying a layer comprising, randomly distributed, an immobilised measurement reagent and an immobilised reference reagent suitable for the desired assay
comprising the steps of (a) forming a patch of suitable reagent(s), carried by zone I on the surface of a sheet material which is to provide part of a multiplicity of the devices, (b) forming a patch of suitable reagent(s), carried by zone II on the surface of an additional structure, involving immobilisation of the measurement reagent and reference reagent, said additional structure together with said sheet material providing for each of the multiplicity of devices a cavity for collecting and retaining a volume of sample liquid in contact with said layers of suitable reagents, and (c) separating the sheet material together with the additional structure into portions each providing one or a plurality of the sample-collecting and testing devices.
Specification