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-10179930-B2
Publication Date
2019-01-15
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 relates to detection units and methods for detecting one or more target analytes in a sample through the formation of a complex that includes a target analyte, a first probe coupled to a particle, and a second probe coupled to a solid support. The complex features an elongated region, which is essential for distinguishing specific binding interactions. The detection method involves measuring particle displacement or Brownian motion, which directly indicates the presence or absence of the target analyte in the sample.
Traditional detection systems, such as immunoassays like ELISA, often face limitations in sensitivity due to low analyte concentrations and significant background noise resulting from non-specific binding events. Existing signal amplification strategies, such as reporter markers, tend to increase both signal and background noise, making it difficult to discriminate between specific and non-specific interactions. This invention addresses these issues by allowing discrimination based on the measurable displacement of particles specifically bound via elongated complexes, which enables accurate detection even at low analyte concentrations.
The core methodology encompasses various embodiments, including the application of external forces (magnetic, fluidic, gravitational, etc.) to the particle or complex, and subsequent measurement of displacement or Brownian motion. The invention also enables multiplexed detection by exploiting elongated regions of varying lengths, allowing simultaneous determination of multiple target analytes. The solution provides a direct and effective approach to identifying specific target-probe interactions amid potential non-specific bindings in complex samples.
Claims Coverage
There are two independent claims in this patent, each introducing distinct but related inventive features for detecting a target analyte using displacement-based discrimination.
Detection of target analyte via displacement or Brownian motion using elongated complex
A method of detecting a target analyte in a sample by: - Providing a complex formed from: - a first probe coupled to a particle and bound to the analyte if present, - a second probe coupled to a solid support and bound to the analyte if present, - the complex incorporates an elongated region. - If the target analyte is present, the particle is indirectly coupled to the solid support via this complex. - Detecting presence of the analyte by measuring either: - the amount of displacement of the particle (after applying a force or by measuring the natural length of the complex), or - the Brownian motion of the indirectly coupled particle, with the measured displacement or Brownian motion indicating presence of the target analyte.
Discrimination and detection by removal of non-specifically bound particles using parallel force
A method of detecting a target analyte in a sample by: - Providing a complex formed from: - a first probe coupled to a particle and bound to the analyte if present, - a second probe coupled to a substantially flat solid support and bound to the analyte if present, - the complex includes an elongated region. - Applying a force to the indirectly coupled particle, with a component parallel to the solid support, to remove non-specifically bound particles. - Identifying the presence of the target analyte by detecting the presence of the particle after the application of force.
The inventive features establish new methods for detecting analytes by leveraging the measurable displacement or Brownian motion of particles linked via elongated regions, and by using parallel forces to selectively remove non-specifically bound particles, thereby providing enhanced specificity and sensitivity compared to previous techniques.
Stated Advantages
Enables discrimination between specific and non-specific binding of particles by measuring particle displacement, allowing more accurate detection even at low analyte concentrations.
Reduces background noise without loss of signal by using elongated complexes that experience lower tension under applied force, preserving specific binding signals while removing non-specific ones.
Provides a simple multiplexing method by utilizing elongated regions of different lengths, enabling detection of multiple target analytes simultaneously in a single assay.
Increases target selectivity through the application of force, which removes particles bound via molecules similar but not identical to the target molecule.
Improves removal of non-specifically bound particles when force parallel to the solid support is applied, as long tethers decrease the force experienced by specifically bound complexes.
Documented Applications
Detection of nucleic acids, including single-stranded DNA, single-stranded RNA, messenger RNA, small interfering RNA, micro-RNA and its precursors, and circulating RNA, from biological samples such as whole blood, serum, plasma, urine, saliva, sputum, and body fluids.
Detection of proteins, including the use of antibodies as probes to identify protein analytes.
Detection of bacterial cells, such as those causing tuberculosis, by targeting and detecting specific RNA molecules like 23S ribosomal RNA in samples (e.g., sputum or blood).
Use in multiplex assays for simultaneous detection and quantification of multiple target analytes based on distinct displacement signatures.
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