The present technology relates generally to systems and methods for assaying one or more analytes within a biological sample. Many embodiments of the present technology relate to systems and methods for lysing cells and assaying for analytes therein.
Diagnosis is the first hurdle in disease management, enabling expedited appropriate treatment in developed settings where sophisticated equipment and trained personnel are available. For example, in the United States, in-vitro diagnostic procedures represent about 1.6% of Medicare spending, yet influence 60-70% of medical decisions. Nucleic acid amplification tests (NAATs) performed in the laboratory represent the pinnacle of sensitive and specific pathogen detection. Unfortunately, this state of the art is also expensive and complex, requiring infrastructure and instrumentation not available in all settings.
The lack of adequate diagnostics is especially troublesome in the case of tuberculosis (TB), which infects approximately one-third of the world's population according to the World Health Organization (WHO). Sixty percent of TB patients only have access to a peripheral level of the health system, where no suitable TB diagnostics exist. Conventional TB diagnostics in low-resource settings, mainly sputum smear microscopy and cell culture, lack the ideal specificity and timeliness. Also, the required equipment is rarely available.
Microfluidic devices have shown promise to enable the type of point-of-care device that could bring NAATs to the point of care in low-resource settings, but sample preparation, such as cell lysis, remains the weak link in microfluidics-based bioassays. Mechanical lysis methods, such as bead beating, are desirable in that one can avoid the need to purify the sample from a chemical lytic agent before the downstream bioassay, but these methods traditionally suffer from relatively complex, user- and power-intensive instruments and protocols.
Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Instead, emphasis is placed on illustrating clearly the principles of the present disclosure.
The present technology is generally related to systems and methods for assaying one or more analytes of a biological sample and, in some embodiments, to systems and methods for lysing cells and assaying one or more analytes contained within the cells. In certain embodiments of the present technology, the system comprises a cap assembly, a detection assembly having one or more detection units, and a vessel having a closed end portion and an open end portion configured to receive a biological sample. The cap assembly includes a porous membrane having a receiving region and a detection region. When the system is assembled (referred to herein as “the assay assembly”), the detection assembly is positioned around the closed end portion of the vessel and the cap assembly engages and seals the open end portion. In this assembled configuration, the receiving region of the porous membrane is fluidly coupled to an open end portion of the vessel, and the detection region of the porous membrane is positioned adjacent a detection unit of the detection assembly. When the assay assembly is in an upright orientation, the receiving region—which is fluidly coupled to the porous membrane—does not contact and/or is not in fluid communication with the biological sample within the vessel. When the assay assembly is inverted, the biological sample contacts the receiving region and wicks through the porous membrane to the detection region for detection by the detection units.
As used herein, the term “porous membrane” refers to a material through which fluid can travel by capillary action. Representative examples of such porous membranes include glass fiber, paper, nitrocellulose, nylon, cellulose, and many other materials recognized by those skilled in the art as capable of serving as a wick in the context of the present technology. In some embodiments, all or part of the porous membrane may include a cellulose ester or a polymeric material (e.g., polyether sulfone (“PES”), polysulfone (“PS”), polyether sulfone (“PES”), polyacrilonitrile (“PAN”), polyamide, polyimide, polyethylene (“PE”), polypropylene (“PP”), polytetrafluoroethylene (“PTFE”), polyvinylidene fluoride (“PVDF”), polyvinylchloride (“PVC”). The porous membrane can be two-dimensional or three-dimensional (when considering its height in addition to its length and width). In some embodiments, the porous membrane is a single layer, while in other embodiments, the porous membrane comprises two or more layers of membrane.
As used herein, the term “wettably distinct” means being capable of being wetted by contact with separate fluids without mixing of the fluids at the point of initial wetting. For example, two input legs are wettably distinct if they are physically separated so that each leg could be brought into contact with a separate fluid reservoir. Pathways can be made wettably distinct by a variety of means including, but not limited to, separation via distinct edges (e.g., cut as separate pathways) and separation via an impermeable barrier.
As used herein, a “biological sample” can be any solid or fluid sample, living or dead, obtained from, excreted by, or secreted by any living or dead organism, including, without limitation, single-celled organisms, such as bacteria, yeast, protozoans, amoebas, multicellular organisms (such as plants or animals, including samples from a healthy or apparently healthy human subject or a human patient affected by a condition or disease to be diagnosed or investigated, such as tuberculosis) and/or soil. Biological samples can include one or more cells, proteins, nucleic acids, etc., as well as one or more buffers. Biological samples can be a liquid phase solution of cells or it may be a solid cell sample such as a cell pellet derived from a centrifugation procedure. As used herein, a “cell” or “cells” can refer to eukaryotic cells, prokaryotic cells, viruses, endospores or any combination thereof. Cells thus may include bacteria, bacterial spores, fungi, virus particles, single-celled eukaryotic organisms (e.g., protozoans, yeast, etc.), isolated or aggregated cells from multi-cellular organisms (e.g., primary cells, cultured cells, tissues, whole organisms, etc.), or any combination thereof, among others. Furthermore, the term “lysis” or “lyse” as used herein refers to disrupting the structural integrity of a cell (e.g., by breaking the cellular membrane of the cell) in order to gain access to materials within the cell.
Use of relative directional language like top, bottom, upper, lower, up, down, upright, upwards, downwards, and others are relative and are not restricted to absolute directions or orientations defined with respect to the surface of the earth.
The housing 202 may further include a plurality of waveguides extending downwardly from each of the openings 209 into an interior region of the housing 202. In some embodiments, the housing 202 of the detection assembly 200 is a solid piece of material, and the waveguides are channels that extend through the solid piece of material. In other embodiments, the housing 202 of the detection assembly 200 is generally hollow, and the waveguides are tubes that extend away from the openings 209 and across the interior region 203 of the housing 202.
In the embodiment shown in
Referring still to
In some embodiments, the detection assembly 200 does not include a PCB (or any chip and/or integrated circuitry) and is configured to visually indicate to the user the presence and/or concentration of a particular analyte in the detection region 411 (discussed in greater detail below with reference to
Each of the indication regions 282 may have a corresponding indicator 284. In the embodiment shown in
It will be appreciated that although the vessel 300 shown in
In order to access certain analytes within the biological sample it may be necessary to lyse or otherwise agitate the biological sample. Accordingly, the systems of the present technology optionally include components or reagents to lyse or otherwise agitate a biological sample. For example, as shown in
The agitator 310 may be pre-loaded in the vessel 300, or the user (not shown) may add the agitator 310 during the assay procedure. The agitator 310 can be generally spherical and configured to be positioned within the vessel 300 adjacent a closed end portion 300a of the vessel 300 when the assembled system 100 is in the upright orientation. In other embodiments, the agitator 310 can have other suitable shapes. For example, in some embodiments, the agitator 310 can be generally cylindrical, disc-shaped, cubical, and/or other suitable polyhedrons and non-polyhedrons. The agitator 310 can be made from a material that is magnetized and creates its own persistent magnetic field, such as a permanent magnet. For example, the agitator 310 can be made from iron, nickel, cobalt, rare-earth metals and some of their alloys (e.g., an Alnico magnet, a neodymium magnet, etc.), naturally occurring minerals such as lodestone, and other suitable materials. As shown in
In some embodiments, the system 100 can include one or more lysis reagents capable of chemically lysing a portion of the biological sample. In certain embodiments, the lysis reagents are selected from the group consisting of proteinases (e.g., achromopeptidase, lysostaphin; etc.) salts (e.g., guanidinium thiocyanate), acids, bases, detergents, and buffers.
Referring still to
The voltage source 250 can be, for example, a battery-powered portable electronic device (e.g., a mobile electronic device) capable of generating an electrical audio signal. For example, the voltage source 250 can include a cell phone, a portable audio device (e.g., a portable mp3 player, a portable radio, a portable cd player, a tape player, etc.), a tablet, a laptop, or other suitable devices.
In some embodiments, the voltage source 250 is configured to deliver a signal having a current of 1 A and an amplitude of 3 V (e.g., with a power of 3 W). In some embodiments, the assembled system 100 may only consume about 100 mW or less. Benchtop power supplies are designed to deliver voltage magnitudes much higher than could be handled by the present system.
The voltage source 250 can be configured to generate and transmit an alternating current that alternates between, for example, about 10 Hz and about 90 Hz (e.g., 30 Hz, etc.). For those embodiments utilizing only a USB connection to the voltage source 250, the system 100 may further include an oscillator (e.g., on the PCB 218) to convert a DC signal to an AC signal. In some embodiments, the voltage source 250 can generate an alternating current that alternates between about 20 Hz and about 60 Hz (e.g., about or equal to 30 Hz, about or equal to 40 Hz, about or equal to 60 Hz, etc.). The voltage source 250 can be connected to the port 208 at the detection assembly 200 via an audio jack, a USB connection, and/or other suitable connections configured to couple to portable electronic devices. In some embodiments, the voltage source 250 can include a display screen (not shown), an electrical output (e.g., an audio jack), and one or more controls. In some embodiments, the display screen is a touch screen. The display screen can indicate to the user various signal parameters, such as the time elapsed, the frequency at which the current is alternating, and the waveform. The voltage source 250 can further include a power button and optional control buttons to adjust one or more of the signal parameters. In some embodiments, the control buttons may be incorporated into a touch-screen display.
The voltage source 250 can further include a processor and memory. The memory can include one or more programs. Each of the programs can include one or more pre-set signal parameters. For example, a first program can output a 30 Hz signal with a sinusoidal waveform, and a second program can output a 40 Hz signal with a square waveform. The programs, however, need not have different values for each parameter. In some embodiments, each of the programs can be tailored to a different lysis procedure. For example, lysis of stronger cells, such as mycobacterium tuberculosis (MTB), may require a higher frequency and/or a longer duration of agitation. As such, the voltage source 250 may contain a program specifically designed for lysis of MTB cells that includes a relatively higher frequency. In some embodiments, one or more programs (e.g., .wav files, .mp3 files, and/or any file that is readable by any device configured to process audio signals) can be downloaded to the voltage source 250 via a hard connection or wirelessly. For example, a frequency and waveform generator application, such as Freq Gen (William Ames), can be downloaded to the voltage source 250 and supply a variety of waveforms at a wide range of frequencies. In some embodiments, the system 100 can further include an amplifier (not shown) to increase the power delivered by the voltage source 250.
In some embodiments, the processor and/or memory may include a program that is configured to generate a signal of varying frequency (e.g. sweep from about 10 Hz to about 150 Hz) and/or complicated wave shapes (e.g., a 30 Hz signal overlaid on a 31 Hz).
Additional details regarding devices, systems and methods for disrupting biological samples for use with the assay systems of the present technology can be found in U.S. patent application Ser. No. 14/601,966, filed Jan. 21, 2015, U.S. Provisional Patent Application No. 61/929,769, filed Jan. 21, 2014, and Buser et al., “Lab on a Chip”, 15, 1994-1997 (2015), each of which is incorporated herein by reference in its entirety.
Referring to
The porous membrane 409 has a receiving region 409 configured to be positioned at the open end portion of the vessel 300 when the system 100 is assembled. In the embodiment shown in
One or more portions of the porous membrane 409 (e.g., receiving region 412, legs 410, and/or detection region 411) may optionally include one or more detection reagents configured to bind to a particular analyte and/or a molecule associated with a particular analyte that indicates the presence and/or amount of the analyte to a user. In one variation of this embodiment, each of the legs 410 includes a different detection reagent configured to detect and/or specifically bind to different analytes. For example, in some embodiments, the detection reagents are fluorescent detection reagents.
In certain embodiments, one or more portions of the porous membrane may have nucleic acid amplification reagents impregnated therein. Nucleic acid amplification reagents may be selected from the group consisting of primers, probes, polymerases, enzymes, deoxynucleoside triphosphate (“dNTP”), nucleic acid control targets, salts, detergents, reducing agents, buffers, glycerol, reagents enabling dry preservation including sugars (e.g., trehalose, dextran, etc.), polyethylene glycol, and others. In certain embodiments the nucleic acid amplification reagents are configured to perform loop-mediated isothermal amplification (“LAMP”), strand displacement amplification (“SDA”), isothermal strand displacement amplification (“iSDA”), recombinase polymerase amplification (“RPA”), and other suitable isothermal nucleic acid amplification reactions. In some embodiments, one or more portions of the porous membrane may additionally or alternatively have protein capture and detection reagents impregnated therein.
Before and/or after coupling the cap assembly 400 to the vessel 300, the electromagnetic coil 204 may optionally receive a current from a voltage source, thereby causing the agitator 310 in the vessel to move (e.g., rotate) and lyse one or more cells within the biological sample. Additionally or alternatively, the system 100 may include one or more lysis reagents to lyse the cells of the biological sample and/or a heating element (described in greater detail below) to aid in lysing the cells of the biological sample.
Referring next to
Several embodiments of the present technology enable competitive, quantitative measurements of nucleic acid analyte molecules within the biological sample. For example, in those embodiments in which the porous membrane 406 includes two or more wettably distinct legs 410, the legs may be impregnated with nucleic acid amplification reagents. Each of the porous membranes can comprise nucleic acid molecules that are complementary to the primer nucleic acid molecules. In certain further embodiments, each of the wettably distinct legs contain different numbers or concentrations of nucleic acid molecules complementary to the primer nucleic acid molecules. The primer nucleic acid molecules and the nucleic acid molecules complementary to the primers can form dimers and thereby inhibit nucleic acid amplification. If roughly the same number of analyte nucleic acid molecules enters each of the wettably distinct legs, and each of the legs contain different numbers or concentrations of the nucleic acid molecules complementary to the primer nucleic acid molecules, then the nucleic acid amplification reactions in each of the wettably distinct legs will be inhibited to variable and known extents.
In certain embodiments, the system 100 and/or cap assembly 400 can include a distributing porous membrane having a first end and a second end and varying widths between the first and second ends, wherein the first porous membrane is in fluidic communication with a first portion of the distributing porous membrane having a first width and the at least second porous membrane is in fluidic communication with a second portion the distributing porous membrane having a second width, and wherein the first width and the second width are different. When the system 100 is flipped from a first orientation to a second orientation, the biological sample is placed in fluid communication with the distributing porous membrane. The biological sample is then wicked through the distributing porous membrane to the other porous membranes. Since the first and second porous membranes have overlapping intersections with the distributing porous membrane of varying areas, the first and second porous membranes will receive varying volumes of fluid from the biological sample. Thus, the distributing porous membrane acts as a volume metering element, automatically metering out different volumes of fluid from the biological sample.
Any of the assay systems disclosed herein can optionally include one or more heating units configured to heat one or more portions of the system. For example, the heating unit may be positioned or otherwise configured to heat at least a portion of the porous membrane, at least a portion of the vessel, and/or at least a portion of the biological sample. Heating one or more portions of the system, such as the vessel and/or the biological sample, may be beneficial for assisting lysing of the biological sample and/or deactivating certain lysis reagents, such as achromopeptidase. The application of heat to the porous membrane may assist in nucleic acid amplification reactions, such as isothermal nucleic acid amplification reactions.
The heating unit(s) may be coupled to the detection assembly 200, the vessel 300, and/or the cap assembly 400. In certain embodiments, the heating unit includes an electrical heating unit that is powered by a voltage source (e.g., voltage source 250 shown in
From the foregoing, it will be appreciated that specific embodiments of the technology have been described herein for purposes of illustration, but that various modifications may be made without deviating from the technology. For example, although many of the embodiments are described above with respect to devices, systems, and methods for lysing cells and/or assaying for analytes contained therein, other embodiments are within the scope of the present technology. For example, devices, systems, and methods of the present technology can be used to disrupt (e.g., mechanically, electrically, and/or chemically) or agitate any non-cellular biological sample (e.g., mucus) and/or non-cellular components of the biological sample.
Additionally, other embodiments of the present technology can have different configurations, components, and/or procedures than those described herein. For example, other embodiments can include additional elements and features beyond those described herein, or other embodiments may not include several of the elements and features shown and described herein. For example, in some embodiments the system 100 does not include the coil and/or agitator and is not configured for connection to a current or power source. In such embodiments, the cells of the biological sample may be lysed prior to delivery to the vessel 300. Moreover, while advantages associated with certain embodiments of the technology have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the technology. Accordingly, the disclosure and associated technology can encompass other embodiments not expressly shown or described herein. Thus, the disclosure is not limited except as by the appended claims.
The present application claims the benefit of U.S. Provisional Patent Application No. 62/253,607, filed Nov. 10, 2015, which is incorporated by reference herein in its entirety.
Number | Date | Country | |
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62253607 | Nov 2015 | US |