Detection units and methods for detecting a target analyte
Inventors
Celedon, Alfredo Andres • Murthy, Saravana Radha Krishna • Xu, Zhiguang • Schultz, Danielle Elise • Horn, Troy Allen
Assignees
Publication Number
US-11505818-B2
Publication Date
2022-11-22
Expiration Date
2035-02-05
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Abstract
The present application relates to detection units and methods for detecting one or more target analytes in a sample using a complex formed by a target and first and second probes, wherein the complex comprises an elongated region, a particle that is coupled to the first probe, and a solid support that is coupled to the second probe. Specific binding of a target analyte can be distinguished from non-specific binding of the particle by measuring the displacement of the particle.
Core Innovation
The invention provides detection units and methods for detecting one or more target analytes in a sample by forming a complex involving a target analyte and first and second probes. This complex is characterized by an elongated region, a particle coupled to the first probe, and a solid support coupled to the second probe. The method allows specific binding of a target analyte to be distinguished from non-specific binding by measuring the displacement or Brownian motion of the particle, as the displacement will depend on the presence and length of the elongated region in the complex.
Conventional detection systems, such as immunoassays, are limited by low analyte concentrations and issues with non-specific interactions, which hinder accurate detection and differentiation between specific and non-specific binding. Techniques that use reporter markers to increase detection signals can also increase background noise, making it difficult to effectively discriminate non-specific binding, particularly at low target concentrations.
The present invention addresses these limitations by utilizing a complex with an elongated region to tether particles to the solid support through specific binding events. By measuring the displacement or Brownian motion of the particle, specific binding can be discerned from non-specific binding, as non-specifically bound particles are displaced less than specifically bound particles. The approach also allows for multiplexed detection by using elongated regions of different lengths for different targets, and application of specific forces (e.g., fluid drag) can selectively remove non-specifically bound particles without significantly reducing the detection signal provided by specifically bound complexes.
Claims Coverage
The claims include one independent claim describing a kit for detecting target analytes, incorporating several inventive features.
Kit for detection with dual probes and elongated region
A kit comprising: - A particle and a solid support. - A first probe configured with one region to directly bind the target analyte and another region to couple to the particle. The first probe cannot specifically couple to the solid support in the absence of analyte. - A second probe configured with one region to directly bind the target analyte at a different location from the first probe and another region to couple to the solid support. The second probe cannot specifically couple to the particle in the absence of analyte. - The first and second probes are configured so that the particle indirectly couples to the solid support only when both probes bind the analyte, forming a complex. - At least one of: the first probe, the second probe, or the region of analyte between their binding locations comprises an elongated region between about 1.0 micron and about 20 microns long.
The inventive features focus on a dual-probe kit configuration enabling indirect coupling of a particle and solid support via a target analyte and an elongated region, enhancing specificity and discrimination of specific binding.
Stated Advantages
Distinguishes specific binding of a target analyte from non-specific binding by measuring displacement or Brownian motion of the particle.
Allows detection of low concentrations of target analytes with reduced background noise caused by non-specific interactions.
Enables simple multiplexing by using elongated regions of different lengths to detect multiple targets in a single assay.
Application of force, such as fluid drag, removes non-specifically bound particles without significantly reducing the signal from specifically bound complexes.
Increases target selectivity by removing particles bound via similar but non-identical molecules.
Measurement of particle displacement can be performed with sub-micrometer resolution in thousands of complexes.
Documented Applications
Detection of target analytes such as nucleic acids (DNA, RNA, micro-RNA, siRNA) or proteins in biological samples.
Detection of pathogenic bacterial cells, such as Mycobacterium tuberculosis, in samples like sputum or blood using specific probes targeting bacterial RNA.
Multiplexed detection of multiple analytes in a single assay by using elongated regions of different lengths for each target.
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