Biosensor apparatus and methods of use

Abstract

Disclosed herein are methods and devices for detecting the presence of an analyte of interest. A biosensor device can include a reaction chamber and an electrochemical detection chamber. The reaction chamber can include at least one immobilized binding site and a probe conjugate adapted to bind to at least one of the target analyte and the immobilized binding site, while the detection chamber can include electrodes for detecting an electrochemical reaction. If present, the target analyte in the fluid sample results in a change in the amount of probe conjugate bound in the reaction chamber, which can be detected electrochemically in the detection chamber.

Description

RELATED APPLICATIONS [0001] This application claims priority as a continuation-in-part to U.S. application Ser. No. 10 / 105,050, entitled “Direct Immunosensor Assay,” filed Mar. 21, 2002, and Ser. No. 10 / 830,841, entitled “Immunosensor,” filed Apr. 22, 2004, both of which are hereby incorporated by reference in their entirety.BACKGROUND OF THE INVENTION [0002] Conventional biomedical sensors, including immunoassays based systems, have been used to report the presence and / or concentration of a wide variety of analytes. Immunoassays are generally classified into two categories: competition assays and sandwich assays. In a competition assay, the antigen in the test sample is mixed with an antigen-probe complex (commonly referred to as a reporter complex) and the mixture then competes for binding to the antibody. The probe may be a radioisotope, a fluorophore, or a chromophore. In a sandwich immunoassay, the antigen in the test sample binds to the antibody and then a second antibody-prob...

AI Technical Summary

Benefits of technology

[0007] In one embodiment, the immobilized binding site includes an antibody adapted to bind to a target antigen and the probe conjugate includes an antibody adapted to bind to a bound target antigen. If a target antigen is present in a fluid sample, the immobilized binding site can bind to one site on the target antigen, and the probe conjugate can bind to another site on the target antigen. The presence of a target antigen in the fluid sample thus results in an increase in the amount of probe bound in the reaction chamber and a reduction in the amount of probe conjugate in the detection chamber.

[0010] In another embodiment disclosed herein, a method of detecting a target antigen in a fluid sample is provided. The method can include the steps of delivering a sample to an biosensor device that includes a reaction chamber and a detection chamber. The sample is allowed to react with immobilized binding sites and a probe conjugate positioned within the reaction chamber. The sample is then moved to a detection chamber, and the method further comprises the step of electrochemically detecting the probe conjugate in the detection chamber. The detection step allows a user to determine if the target antigen is present in the sample based on the level of probe conjugate detected in the detection chamber. The method can also include the step of quantifying the amount of target antigen in the sample based on electrical signals received from the detection chamber.

Problems solved by technology

The washing steps introduce complexity into the assay procedure and can generate biohazardous liquid waste.

Most of the quantitative methods involve expensive pieces of equipment, such as scintillation counters (for monitoring radioactivity), spectrophotometers, spectrofluorimeters (see, e.g., U.S. Pat. No. 5,156,972), surface plasmon resonance instruments (see, e.g., U.S. Pat. No. 5,965,456), and the like.

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