US-20260126392-A1 - ADDRESSING LIGHT ABSORBANCE DURING INTERFEROMETRIC TESTING THROUGH ALGORITHMIC DECONVOLUTION AND COMPUTATION

US20260126392A1US 20260126392 A1US20260126392 A1US 20260126392A1US-20260126392-A1

Abstract

Introduced here is an approach to programmatically addressing the absorbance of light by analyte molecules whose binding, for example, to an interferometric sensor, is being monitored by an interferometric sensing system. A first light signal may be shone upon a biolayer over the course of a biochemical test, and the light reflected by the biolayer may form a second light signal that is detectable by a detector of an interferometric sensing system. Through analysis of the second light signal, the second light signal can be deconvolved into a reflection component and an absorbance component. If the principal component of the second light signal is the reflection component, then one algorithm may be employed to establish the binding magnitude. If the principal component of the second light signal is the absorbance component, then another algorithm may be employed to establish the binding magnitude.

Inventors

Genqian LI
Dianzhuang Wang
Jessie Peh
Ao-Mei Lee

Assignees

ACCESS MEDICAL SYSTEMS, LTD.

Dates

Publication Date: 20260507
Application Date: 20251230

Claims (20)

1 . A method for addressing absorption of light by a biolayer formed along an end of a probe, the method comprising: obtaining, by a processor, a dataset that includes (i) a reference signal and (ii) a plurality of signals generated after the reference signal, wherein each signal of the plurality of signals is generated by an interferometric sensing system that is configured to measure light reflected by the end of the probe that is suspended in a liquid sample and upon which the biolayer is formed; comparing, by the processor, each signal of the plurality of signals to the reference signal, so as to produce a plurality of subtraction curves; and for each signal of the plurality of signals, calculating, by the processor, an absorbance ratio based on an analysis of a corresponding one of the plurality of subtraction curves; determining, by the processor, whether a principal component of that signal is reflection or absorption based on the absorbance ratio; and computing, by the processor, a binding magnitude based on the principal component.
2 . The method of claim 1 , wherein the plurality of signals are acquired, from the interferometric sensing system, in real time as the plurality of signals are generated by the interferometric sensing system.
3 . The method of claim 1 , further comprising: calculating, by the processor, an average absorbance ratio for the plurality of signals based on the absorption ratios calculated for the plurality of signals; comparing, by the processor, the average absorbance ratio to a threshold; and in response to a determination that the average absorbance ratio is greater than the threshold, assigning, by the processor, the plurality of signals to an absorbance category.
4 . The method of claim 3 , wherein said computing comprises: establishing the binding magnitude for each of the plurality of signals based on an asymmetry component in a corresponding subtraction curve.
5 . The method of claim 1 , further comprising: calculating, by the processor, an average absorbance ratio for the plurality of signals based on the absorption ratios calculated for the plurality of signals; comparing, by the processor, the average absorbance ratio to a threshold; and in response to a determination that the average absorbance ratio is less than the threshold, assigning, by the processor, the plurality of signals to a reflectance category.
6 . The method of claim 5 , wherein said computing comprises: establishing the binding magnitude for each of the plurality of signals by computing a cross-correlation value.
7 . The method of claim 1 , further comprising: posting the binding magnitudes computed for the plurality of signals on a plot that is viewable on an interface.
8 . A non-transitory medium storing instructions that, when executed by a processor of an interferometric sensing system configured to measure binding of analyte molecules in a liquid sample to a probe through analysis of light reflected by a biolayer formed along a distal end of the probe, cause the processor to perform operations comprising: for each signal of a plurality of signals, each of which is representative of a plurality of values indicative of intensity of the light across a plurality of wavelengths at a corresponding point in time, establishing an absorbance ratio based on an analysis of a curve that is produced based on a comparison of the corresponding plurality of values to another plurality of values that is associated with a reference signal; in response to a determination, based on the absorbance ratio, that a principal component of that signal is reflection, computing a binding magnitude so as to have an absolute value of that signal as the binding magnitude; in response to a determination, based on the absorbance ratio, that the principal component of that signal is absorption, computing a binding magnitude based on an asymmetric component of the curve; and causing display of the binding magnitudes computed for the plurality of signals on a plot that is viewable on the interferometric sensing system.
9 . The non-transitory medium of claim 8 , further comprising: generating the plurality of signals by emitting the light at the plurality of wavelengths along a length of the probe and then recording the intensity of the light, as reflected by the biolayer, at the plurality of wavelengths.
10 . The non-transitory medium of claim 8 , wherein the reference signal is a first signal generated following an initiation phase in which measurements generated by the interferometric sensing system are allowed to become less noisy.
11 . The non-transitory medium of claim 8 , wherein the reference signal is generated by the interferometric sensing system immediately preceding the plurality of signals.
12 . The non-transitory medium of claim 8 , wherein the operations further comprise: decomposing the curve into (i) an antisymmetric component that corresponds to phase shift and (ii) the asymmetric component that corresponds to absorption.
13 . The non-transitory medium of claim 12 , wherein to compute the binding magnitude when the principal component is absorption, (i) the asymmetric component is divided by an average of at least some pixels of a frame of that signal, so as to produce a less noisy asymmetric component, (ii) a root is taken of the less noisy asymmetric component, and (iii) the root of the less noisy asymmetric component is multiplied by a coefficient.
14 . The non-transitory medium of claim 8 , wherein the operations further comprise: applying a moving average filter to the plurality of signals, so as to compute a moving average of each signal of the plurality of signals.
15 . The non-transitory medium of claim 14 , wherein the operations further comprise: generating the moving average filter by selecting a boxcar function as an impulse response of a filter.
16 . A non-transitory medium storing instructions that, when executed by a processor, cause the processor to perform operations comprising: acquiring a plurality of signals, each of which is generated by an interferometric sensing system that is configured to measure light reflected by an end of a probe that is suspended in a liquid sample and upon which a biolayer forms; comparing each signal of the plurality of signals to a reference signal, so as to produce a series of curves, each of which is representative of a difference between a corresponding one of the plurality of signals and the reference signal; and for each signal of the plurality of signals, determining whether a principal component of that signal is reflection or absorption based on a corresponding one of the plurality of curves; and computing a binding magnitude of that signal based on the principal component.
17 . The non-transitory medium of claim 16 , wherein the operations further comprise: for each signal of the plurality of signals, calculating an absorbance ratio based on an analysis of the corresponding one of the plurality of curves; wherein said determining is based on the absorbance ratio.
18 . The non-transitory medium of claim 16 , wherein the operations further comprise: causing display of the binding magnitudes computed for the plurality of signals on a plot that is viewable on an interface.
19 . The non-transitory medium of claim 18 , wherein the interface is viewable on the interferometric sensing system.
20 . The non-transitory medium of claim 16 , wherein said comparing, said determining, and said computing are performed as the plurality of signals are acquired, such that the binding magnitude is established in real time.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of U.S. application Ser. No. 19/102,010, filed Feb. 7, 2025, which is a 35 USC § 371 (c) entry of International Application No. PCT/US2023/073559, filed on Sep. 6, 2023, which claims priority to, and the benefit of, U.S. Provisional Application No. 63/374,724, filed on Sep. 6, 2022, each of which is incorporated herein by reference in its entirety. FIELD OF THE INVENTION Various embodiments concern approaches to programmatically addressing the absorbance of light by analyte molecules whose binding, for example, to an interferometric sensor, is being monitored by an interferometric sensing system and associated computer programs. BACKGROUND Diagnostic tests based on binding events between analyte molecules and analyte-binding molecules are widely used in medical, veterinary, agricultural, and research applications. These diagnostic tests can be employed to detect whether analyte molecules are present in a sample, the amount of analyte molecules in a sample, or the rate of binding of analyte molecules to the analyte-binding molecules. Together, an analyte-binding molecule and its corresponding analyte molecule form an analyte-anti-analyte binding pair (or simply “binding pair”). Examples of binding pairs include complementary strands of nucleic acids, antigen-antibody pairs, and receptor-receptor binding agents. The analyte can be either member of the binding pair, and the anti-analyte can be the other member of the binding pair. Historically, diagnostic tests have employed a solid, planar surface having analyte-binding molecules immobilized thereon. Analyte molecules in a sample will bind to these analyte-binding molecules with high affinity in a defined detection zone. In this type of assay, known as a “solid-phase assay,” the solid surface is exposed to the sample under conditions that promote binding of the analyte molecules to the analyte-binding molecules. Generally, the binding events are detected directly by measuring changes in mass, reflectivity, thickness, color, or another characteristic indicative of a binding event. For example, when an analyte molecule is labeled with a chromophore, fluorescent label, or radiolabel, the binding events are detectable based on how much, if any, label can be detected within the detection zone. Alternatively, the analyte molecule could be labeled after it has bound to an analyte-binding molecule within the detection zone. U.S. Pat. No. 5,804,453 discloses a method of determining the concentration of a substance in a sample solution, using an optical fiber having a reagent (i.e., a capturing molecule) coated on its distal end to which the substance binds. The distal end is then immersed into the sample solution containing the substance. Binding of the substance to the reagent generates an interference pattern and is detected by a spectrometer. U.S. Pat. No. 7,394,547 discloses a biosensor with a first optically transparent element that is mechanical attached to an optical fiber tip with an air gap between them. A second optical element that acts as the interference layer with a thickness greater than 50 nanometers (nm) is then attached to the distal end of the first optical element. The biolayer is formed on the peripheral surface of the second optical element. An additional reflective surface layer with a thickness between 5-50 nm and a refractive index greater than 1.8 is coated between the interference layer and the first optical element. The principle of detecting an analyte in a sample based on the changes of spectral interference is described in this reference, which is incorporated herein by reference in its entirety. U.S. Pat. No. 7,319,525 discloses a different configuration in which a section of an optical fiber is mechanically attached to a tip connector consisting of one or more optical fibers with an air gap between the proximal end of the optical fiber section and the tip connector. The interference layer and then the biolayer are built on the distal surface of the optical fiber section. Although the prior art provides functionality in utilizing biosensors based on thin-film interferometers, there exists a need for improvements in the performance of these interferometers. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A illustrates one example of a binding signal. FIG. 1B illustrates how, in some situations, the binding signal may experience a downward shift rather than an upward shift in magnitude. FIG. 2A depicts a biosensor interferometer that includes a light source, a detector, a waveguide, and an optical assembly (also called a “probe”). FIG. 2B depicts an example of a probe. FIG. 3 depicts an example of a probe in accordance with various embodiments. FIG. 4 depicts another example of a probe in accordance with various embodiments. FIGS. 5A-B illustrate the principles of detection in a thin-film interferometer. FIG. 6 depicts an example of a slide in accordance with various embod