Wide range luminescent immunoassays
AssigneeAccess Medical Systems, Ltd.
InventorRobert F. ZUK
Life of this patent
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Abstract
The present invention relates to a method for quantitating an analyte having a wide range concentration in a single assay without having to dilute the sample and repeating the assay. The key feature of the invention is having two cycles of events including sample binding to probe, binding reactions, and detection. After the first cycle of binding and detecting, the probe is dipped into the same sample vessel to bind additional analyte in the sample vessel at a condition that is more favorable to binding than the condition in the first cycle.
Claims18
A method of detecting an analyte in a wide concentration range in a liquid sample, comprising the steps in the order of:
- (a) obtaining a probe having a first antibody immobilized on the tip of the probe, wherein the diameter of the tip surface is ≦5 mm;
- (b) dipping the probe tip into a sample vessel containing a sample solution having an analyte for 10 seconds to 2 minutes and flowing the sample solution laterally in the sample vessel at 0-500 rpm, to bind the analyte to the first antibody on the probe tip;
- (c) dipping the probe tip into a reagent vessel containing a reagent solution comprising a reagent of a second antibody conjugated with a first member of a binding pair to bind the reagent to the analyte;
- (d) dipping the probe tip into a first washing vessel containing a first wash solution to wash the probe tip;
- (e) dipping the probe tip into an amplification vessel containing an amplification solution comprising a second member of the binding pair conjugated with one or more luminescent labels, to form an immunocomplex of the analyte, the first antibody, the second antibody, and the first and the second members of the binding pair on the probe tip;
- (f) dipping the probe tip into a second washing vessel containing a second wash solution to wash the probe tip;
- (g) obtaining a first result by measuring the luminescent signal of the immunocomplex formed on the probe tip;
- (h) dipping the probe tip into the same sample vessel for 1-30 minutes and flowing the sample solution laterally in the sample vessel at 200-1200 rpm, to bind additional analyte in the sample to the first antibody on the probe tip;
- (i) repeating steps (c) to (f) 1-10 times;
- and
- (j) obtaining a second result by measuring the luminescent signal of the final immunocomplex formed on the probe tip;
- and
- (k) combining the two results and analyzing the analyte concentration in a wide range;
- wherein the first antibody and the second antibody are antibodies against the analyte.
A method of detecting an analyte in a wide concentration range in a liquid sample, comprising the steps in the order of:
- (i) obtaining a probe having a first antibody immobilized on the tip of the probe, wherein the diameter of the tip surface is ≦5 mm;
- (ii) dipping the probe tip into a sample vessel containing a sample solution having an analyte for 10 seconds to 2 minutes and flowing the sample solution laterally in the sample vessel at 0-500 rpm, to bind the analyte to the first antibody on the probe tip;
- (iii) dipping the probe tip into a reagent vessel containing a reagent solution comprising a second antibody conjugated with fluorescent labels, to form an immunocomplex of the analyte, the first antibody, and the second antibody;
- (iv) dipping the probe tip into a washing vessel containing a wash solution to wash the probe tip;
- (v) obtaining a first result by measuring the luminescent signal of the first immunocomplex formed on the probe tip;
- (vi) dipping the probe tip into the same sample vessel for 1-30 minutes and flowing the sample solution laterally in the sample vessel at 200-1200 rpm, to bind additional analyte in the sample to the first antibody on the probe tip;
- (vii) repeating steps (iii) and (iv);
- (viii) obtaining a second result by measuring the luminescent signal of the final immunocomplex formed on the probe tip;
- and
- (ix) combining the two results and analyzing the analyte concentration in a wide range;
- wherein the first antibody and the second antibody are antibodies against the analyte.
Dependencies are inferred from the claim text.