Abstract: The present invention provides a high sensitivity immunoassay method for determining the concentration of an analyte in a sample based on interferometry. The present invention provides a high molecular weight conjugate comprising multiple streptavidins and horse radish peroxidases (HRP) and uses this conjugate to increase the sensitivity of a biochemical assay. The high molecular weight conjugate comprises at least 2 HRPs, preferably 4 HRPs and binds a precipitating HRP substrate to a solid phase to increase the signal of a biochemical assay.

Abstract: The present invention is directed to a method of determining DNA concentration in a DNA virus. The invention features three basic steps. The initial step is the specific capture of a defined amount of virus capsid particles on a first solid phase. The second step is lysis of the capsid to release the virus DNA from the first solid phase into a lysis solution. After separating the lysis solution from the first solid phase, the third step is contacting the lysis solution with a second solid phase. The second solid phase captures total DNA derived from the captured capsid. The present invention is also directed to a method for measuring the percentage of full virus capsid, comprising first determining the ssDNA concentration in viruses, and then converting the ssDNA concentration to percentage of full virus capsid using a calibration curve having DNA concentration plotted against standards of % of full capsids.

Abstract: The present invention is directed to an immunoassay method for detecting an analyte in a liquid sample; and provides accuracy and reproducibility for both high concentration and low concentration samples. The method uses both fluorescence marker and chemiluminescence marker, and reads both fluorescence signal and chemiluminescence signal. The analyte concentration is determined based on either a calibration curve for the fluorescence signal, or a calibration curve chemiluminescence signal, using a pre-established analyte concentration value.

Abstract: The present invention is directed biochemical assay methods with regenerated substrate surface for immunoassay reactions. The methods clean a ceramic or glass substrate surface with atmospheric gas plasma and then coat the cleaned surface directly (without further modification of the cleaned surface) with a hapten-polymer conjugate, a protein, or an anti-non-human IgG antibody as a first layer on the substrate surface for subsequence assay reactions. After the completion of each cycle of reactions, the substrate is cleaned by the same plasma cleaning procedure, to elute the organic molecules formed on the substrate surface and to regenerate the substrate for another cycle of immunoassay reactions. The regeneration protocols can be repeated 1-10 times and maintains acceptable assay performance.

Abstract: The present invention is directed to biochemical assay methods, which uses a biotin-immobilized solid support surface for quantitating an analyte or measuring kinetic binding in different samples, from about 3 to 20 times, while maintaining acceptable assay performance. The methods use a streptavidin capture solution comprising streptavidin or preferably streptavidin polymers. The biotin-immobilized solid support surface is regenerated after each cycle of reactions by contacting the surface in an acidic solution having pH about 1-4, followed by DMSO. The regeneration step removes the bound immunocomplex and leaves the biotin on the surface.

Abstract: This invention relates to an apparatus for conducting immunoassay test. The apparatus includes a groove unit having a groove along a vertical direction configured to hold a rod-shaped portion of a probe along the vertical direction, and a push pin configured to move along a horizontal direction, the push pin being capable of residing at a first position and a second position. A tip of the push pin is capable of pressing the rod-shaped portion of the probe against the groove when the push pin resides at the first position. The distance between the tip of the push pin and the groove is larger than a diameter of the rod-shaped portion of the probe when the push pin resides at the second position.

Abstract: The present invention is directed to biochemical assay methods, which re-use a hapten-immobilized test probe and reagents for quantitating an analyte or measuring kinetic binding in different samples, anywhere from about 3 to 20 times, while maintaining acceptable assay performance. The methods use a conjugate solution either comprising (i) an anti-hapten antibody and a capture antibody against an analyte, or (ii) an anti-hapten antibody and streptavidin, in each cycle and regenerate the hapten-coated test probe by dipping the test probe in an acidic solution having pH about 1-4, optionally further dipping in a DMSO solution, after the completion of each cycle of reaction. The robustness of the hapten-immobilized solid phase allows utilization of denaturation reagents for efficient elution of the immune complexes after each cycle without compromising the binding activity of the hapten on the solid phase.

Abstract: This invention relates to an apparatus for conducting immunoassay test. The apparatus includes a groove unit having a groove along a vertical direction configured to hold a rod-shaped portion of a probe along the vertical direction, and a push pin configured to move along a horizontal direction, the push pin being capable of residing at a first position and a second position. A tip of the push pin is capable of pressing the rod-shaped portion of the probe against the groove when the push pin resides at the first position. The distance between the tip of the push pin and the groove is larger than a diameter of the rod-shaped portion of the probe when the push pin resides at the second position.

Abstract: This invention relates to an apparatus for conducting immunoassay test. The apparatus includes a groove unit having a groove along a vertical direction configured to hold a rod-shaped portion of a probe along the vertical direction, and a push pin configured to move along a horizontal direction, the push pin being capable of residing at a first position and a second position. A tip of the push pin is capable of pressing the rod-shaped portion of the probe against the groove when the push pin resides at the first position. The distance between the tip of the push pin and the groove is larger than a diameter of the rod-shaped portion of the probe when the push pin resides at the second position.

Abstract: The present invention is directed to a method of measuring the dissociation rate of the binding of an antibody to an antigen. The method has two phases: a first phase of binding and a second phase of dissociation. The first phase of the assay has a probe coated with an antigen, or protein G, or an anti-human IgG Fc antibody. The probe is immersed in a sample solution containing an antibody, followed by a wash sequence, then the probe is transferred to a reagent with a biotinylated antigen. After an incubation, the antibody bound on the probe binds to the biotinylated antigen to form an immune complex. Fluorescent signal is produced by immersing the probe in a reagent having a fluorescent tagged streptavidin. The last step of the first phase is a measurement of fluorescent on the probe tip.

Abstract: This invention relates to an apparatus for conducting immunoassay test. The apparatus includes a groove unit having a groove along a vertical direction configured to hold a rod-shaped portion of a probe along the vertical direction, and a push pin configured to move along a horizontal direction, the push pin being capable of residing at a first position and a second position. A tip of the push pin is capable of pressing the rod-shaped portion of the probe against the groove when the push pin resides at the first position. The distance between the tip of the push pin and the groove is larger than a diameter of the rod-shaped portion of the probe when the push pin resides at the second position.

Abstract: This invention relates to an apparatus for conducting immunoassay test. The apparatus includes a groove unit having a groove along a vertical direction configured to hold a rod-shaped portion of a probe along the vertical direction, and a push pin configured to move along a horizontal direction, the push pin being capable of residing at a first position and a second position. A tip of the push pin is capable of pressing the rod-shaped portion of the probe against the groove when the push pin resides at the first position. The distance between the tip of the push pin and the groove is larger than a diameter of the rod-shaped portion of the probe when the push pin resides at the second position.

Abstract: The present invention is directed immunoassay methods, which re-use a hapten-immobilized test probe and reagents for quantitating an analyte in different samples, anywhere from about 3 to 20 times, while maintaining acceptable clinical assay performance. The methods use a dual antibody conjugate solution comprising an anti-hapten antibody and a capture antibody against the analyte in each cycle. After the completion of each cycle of reaction, the test probe is dipped in an acidic solution having pH about 1-4, to elute the immunocomplex formed on the probe and to regenerate the hapten-immobilized probe. The robustness of the hapten-coated solid phase allows utilization of multiple denaturation reagents for efficient elution of the immune complexes after each cycle without compromising the binding activity of the hapten on the solid phase.

Abstract: This invention relates to an apparatus for conducting immunoassay test. The apparatus includes a groove unit having a groove along a vertical direction configured to hold a rod-shaped portion of a probe along the vertical direction, and a push pin configured to move along a horizontal direction, the push pin being capable of residing at a first position and a second position. A tip of the push pin is capable of pressing the rod-shaped portion of the probe against the groove when the push pin resides at the first position. The distance between the tip of the push pin and the groove is larger than a diameter of the rod-shaped portion of the probe when the push pin resides at the second position.

Abstract: The present invention is directed to methods for increasing sensitivities of immunoassays. The invention utilizes an acid elution condition that preferentially elute specifically bound immune complexes over non-specifically bound complexes from a solid phase, and designs immunoassay protocols that improve the ratio of specific binding to non-specific binding and thereby improving assay sensitivity. The protocol determines the signal of the labeled immunocomplexes eluted from a solid phase.

Abstract: The present invention is directed an immunoassay method, which re-uses an antibody-immobilized test probe and reagents for quantitating an analyte in different samples, anywhere from about 3 to 20 times, while maintaining acceptable clinical assay performance. The method regenerates the test probe by dipping the test probe in an acidic solution having pH about 1-4, after the completion of each cycle of reaction. The present invention is also directed to a unitized cartridge (a strip) for an immunoassay test. Each unitized cartridge contains all necessary reagents can be used for 3-20 cycles to measure 3-20 different samples.

Abstract: The present invention is directed to methods for increasing sensitivities of immunoassays. The invention utilizes an acid elution condition that preferentially elute specifically bound immune complexes over non-specifically bound complexes from a solid phase, and designs immunoassay protocols that improve the ratio of specific binding to non-specific binding and thereby improving assay sensitivity. The protocol determines the signal of the labeled immunocomplexes eluted from a solid phase.

Abstract: The present invention is directed to a luminescent immunoassay method for detecting an analyte in a liquid sample with high sensitivity. The invention provides a unique combination of (i) using a probe having a small sensing surface area for binding analyte molecules, (ii) using a high molecular weight branched polymer conjugated with multiple binding molecules and multiple luminescent labels, and (iii) cycling the probe having immunocomplex formed back to the reagent vessel and amplification vessel 1-10 times and repeating the reaction with the reagent and the amplification polymer, to improve the sensitivity of detection level. For each cycling, the luminescent signal is increased significantly over the noise. The present invention is also directed to an electrochemiluminescent detection system for measuring a chemiluminescent signal on a probe tip.

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.

Abstract: This invention relates to an apparatus for conducting immunoassay test. The apparatus includes a groove unit having a groove along a vertical direction configured to hold a rod-shaped portion of a probe along the vertical direction, and a push pin configured to move along a horizontal direction, the push pin being capable of residing at a first position and a second position. A tip of the push pin is capable of pressing the rod-shaped portion of the probe against the groove when the push pin resides at the first position. The distance between the tip of the push pin and the groove is larger than a diameter of the rod-shaped portion of the probe when the push pin resides at the second position.