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-12291741-B2
Publication Date
2025-05-06
Expiration Date
2035-02-05
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
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 concerns detection units and methods for detecting target analytes in a sample by using a complex formed by specific interactions among a target analyte, a first probe, and a second probe. The first probe is coupled to a particle, and the second probe is coupled to a solid support. When both probes bind to the target analyte, the particle becomes indirectly tethered to the solid support via the complex, which includes an elongated region.
A key challenge addressed is the difficulty of reliably detecting low concentrations of target analytes due to non-specific interactions in conventional systems, such as immunoassays, where background noise arises from non-specific binding of signal-producing particles or molecules. Existing strategies increase signal but also background noise, making it hard to distinguish specific from non-specific binding, especially at low analyte concentrations.
The present invention offers a solution by measuring the displacement or Brownian motion of a particle indirectly coupled via an elongated region of the complex. Specific binding is distinguished from non-specific binding based on the amount of particle displacement, since specifically coupled particles exhibit a displacement related to the elongated region's length, while non-specifically bound particles are displaced less. This approach allows for sensitive and selective detection of target analytes by differentiating specific complexes from non-specific interactions using measurable physical movement.
Claims Coverage
There are three main independent inventive features in the claims, focusing on the structure of the kit, the nature of the detectable particle and coupling, and a method for detecting analytes based on complex formation and particle displacement or motion.
Kit comprising first and second probes with selective binding and elongated complex
A kit includes: - A first probe with a first region to directly bind the target analyte at a first location and a second region to couple to a particle, where the first probe cannot specifically couple to a solid support in the absence of the analyte. - A second probe with a first region to directly bind the analyte at a second, different location and a second region to couple to the solid support, where the second probe cannot specifically couple to the particle in the absence of the analyte. - The probes form a complex with the analyte (if present) that allows the particle to be indirectly coupled to the solid support, and the length of the complex from the particle coupling site to the solid support coupling site is about 1.0 micron to about 20 microns.
Kit with detectable particle and specific coupling dependent on analyte presence
A kit includes: - A first probe with a region to directly bind the analyte at a first location and a second region to couple to a detectable particle, such that the first probe cannot specifically couple to the solid support without the analyte. - A second probe with a region to bind the analyte at a second different location and a region to couple to the solid support, such that the second probe cannot specifically couple to the detectable particle without the analyte. - The complex formed (first probe, second probe, analyte, and detectable particle) can couple to the solid support and has a length from the particle coupling site to the solid support coupling site of about 1.0 micron to about 20 microns.
Method for detecting an analyte using a complex with an elongated region and force/motion measurement
A method comprises: - Providing a detectable particle indirectly coupled to a solid support via a complex formed from: - A first probe that binds the analyte at a first location and couples to the particle, incapable of coupling to the solid support without the analyte. - A second probe that binds the analyte at a second, different location and couples to the solid support, incapable of coupling to the particle without the analyte. - The analyte and at least one of: the first probe, the second probe, or a region of the analyte between the binding sites, including an elongated region of about 1.0 micron to about 20 microns. - Either applying a force to the complex or measuring Brownian motion of the detectable particle.
The inventive features broadly establish kits and methods for analyte detection through formation of a specific elongated complex that enables particle-based discrimination of specific binding events via displacement or motion analysis.
Stated Advantages
Specific binding of target analyte can be distinguished from non-specific binding of the particle by measuring particle displacement.
The invention enables sensitive detection of low concentrations of target analytes, particularly by reducing background noise from non-specific binding.
Using a complex with an elongated region allows for multiplexing—the simultaneous detection of multiple targets in a single assay by associating different elongated region lengths with different target analytes.
Application of force to the complex increases target selectivity by removing particles bound via similar, but non-target, molecules.
Applying a force substantially parallel to the solid support removes non-specifically bound particles without significantly reducing the specific signal.
Documented Applications
Detection of natural, synthetic, modified, or unmodified nucleic acids or proteins in biological samples.
Detection of bacterial cells, such as those causing tuberculosis in humans, using nucleic acid probes targeting bacterial RNA.
Detection of small nucleic acids, including micro-RNA, small interfering RNA, and their precursors, as well as fragmented DNA molecules in body fluids.
Interested in licensing this patent?