Patent Application
20220061823
This disclosure relates to articles and methods for obtaining exhaled respiratory specimens for the purpose of diagnostic testing for infectious agents.
Global responses to droplet-spread viruses, such as the influenza virus, have required tracking and tracing programs that require consistent diagnostic testing of individuals for the infectious agent and tracing locations and individuals that have been exposed to infection. The diagnostic tests require, as inputs for analysis, biological specimens sampled from healthy individuals and patients, who may or may not be symptomatic, and may or may not be infected. Tests for respiratory infections are commonly performed on saliva, nasopharyngeal, oropharyngeal, nasal mid-turbinate, and anterior nares specimens. These specimens are most frequently collected by a range of invasive sampling methods, which include swabbing nasal and oral passages with flocked, spun polyester, or tapered swabs, and saline washes using bulbs, syringes, or vacuum-assisted aspiration. Diagnostic tests can also be performed on specimens extracted from the lower respiratory tract, which can be sampled through the spontaneous or induced production of sputum, aspiration, or bronchoalveolar lavage.
These collection methods, however, require that individuals either visit a clinician or be sent specialized equipment for collecting samples. As a result, the frequency at which individuals are tested is limited by the availability of clinicians and equipment. Testing aerosols bearing infectious agents from ambient circulating air has proven even more difficult, requiring expensive and complicated machinery that involves cooling air to collect liquid condensate. Moreover, many machines used to draw pathogens out of air end up shredding the pathogens they are meant to capture, rendering the pathogens unrecoverable for analysis. Without simple, frequent and readily available testing of individuals and locations, a virus can continue to spread through a population, threatening to overload local medical systems, and resulting in thousands or hundreds of thousands of preventable deaths.
The present invention provides articles, devices, and methods for collecting respiratory droplets directly from any source of respiratory droplets and commonly-used devices, for example face masks and air handling systems. As a result, respiratory droplets and their contents may be collected from individuals during their day-to-day activities without the need for a clinical visit or without the need for expensive or complicated at-home tests. The invention provides a layer containing a material capable of adsorbing or absorbing respiratory droplets. For example, the material may be a hygroscopic layer (that may be removable) of a facemask or a layer on an air filtration system that, in either case captures exhaled droplets, are contemplated by the invention. The common feature of articles and devices of the invention is the use of a material, such as a hygroscopic material, to collect droplets from any source in a manner that allows the droplets to be recovered from the material and analyzed for the presence of an infectious agent or its associated proteins or nucleic acids. In the case of a face mask, the source is moisture and respiratory droplets from the nose or mouth. In the case of other systems, such as HVAC, air handlers, filters and the like, the sources are aerosolized droplets trapped from the environment. To facilitate analysis, the article or collection portion of a device of the invention preferably comprises a hygroscopic material that is capable of adsorbing or absorbing moisture from any source, such that the contents of the respiratory droplets can be readily recovered. For example, when using an adsorbing material, an aqueous buffer can be used to elute the droplets from the article to recover the droplets for analysis.
Articles of the invention may be included in or configured to be used as collection devices and day-to-day use devices. For example, the invention may comprise a hygroscopic layer, which may be a removable insert of a face mask. Exhaled viral particles are captured by the layer, which may then be submitted for analysis. The face mask may be a surgical mask, such as an N95 surgical mask. Traditionally, the materials used in surgical masks would not normally adsorb or absorb droplets that could be later tested. This is because droplets cannot be collected from the material of surgical masks in the quantities and at a quality that would allow the droplets to be tested. By the present invention, comprising an article that is a removable insert, testing can easily be accomplished by removing the insert and submitting it for testing. Advantageously, the article has the ability to accumulate respiratory droplets and their contents from any source for the entire duration of time that the article is employed, leading to increased sampling of exhaled infectious particles over time. This both increases the viral (infectious agent) load being tested and also allows for sampling of infectious agents over a period of time, rather than at only a single point in time. Infected individuals can then be easily identified, and viral infections can be tracked and traced and the quantity of infectious agent released over time calculated which may further inform risk of spread of infection.
A key feature of the invention is adsorbent or absorbent adherence, using any known material, for example a hygroscopic material, of respiratory droplets from any source. The respiratory droplets may comprise viral particles, and may be collected proximal to a point at which the droplets would typically be dispersed in the environment. Thus, a device of the invention may be a face mask or a filter in an air distribution system, dehumidifier, fan and the like. In the context of a face mask, the invention comprises an outer layer and an inner layer comprising an absorbent or adsorbent material capable of collecting respiratory droplets such that the contents of said droplets can be recovered for analysis. The droplets recovered for the analysis can be analyzed for the presence and/or identify of viral particles.
Advantageously, the material used in the article of the invention can be any material capable of adsorbing or absorbing respiratory droplets. For example, the material may comprise a hygroscopic material, such as a desiccant. The desiccant may be a silica-based desiccant, such as a silica gel. The material may be a superabsorbent polymer, for example a sodium polyacrylate. This contrasts with existing methods for the analysis of air, which collect exhaled condensation through the use of expensive and often cost prohibitive machinery.
The article may also be provided in any available shape suited for the intended use. For example, the article may be shaped as an insert for a face mask. The article may also be shaped to filter circulating air. For example, the article may be shaped as a filter for an HVAC system or for a circulating air vent.
The article of the invention may also be shaped to be included in a collection device. The article of may also be shaped to fit within a collector tube. For example, the collector tube may be a nasal exhalant collector tube. The collector tube may be an oral exhalant collector tube. Advantageously, the article may be shaped as dispersible beads within the collector tube. The collection device may be a hand-held collection device. For example the device may be a lollipop-type device that can be held by the user in front of their face. The user may hold the article up to their face and exhale onto the article. The device may be a tea-bag type device, in which the article is part of a series of layers and exhaled droplets may be collected within those layers. The article may also be shaped as a straw-like collection device or to fit within a straw-like collection device. The article may also be free standing. For example, the article may lay flat on a surface and collect respiratory droplets from ambient or circulated air that comes in contact with the surface.
The invention also provides devices comprising the article of the invention. For example, the invention provides face masks, such as surgical masks, filters for circulating air or ambient air, such as filters for HVAC systems, filters for ventilation systems, and filters for a fans and collection device, such as oral collector tubes, nasal collector tubes, hand-held lollipop devices, hand-held tea-bag devices, surface-resting devices, straw-based devices, or inserts for a straw-based devices, comprising the article of the invention.
The invention also provides for methods of sampling respiratory droplets using articles and devices of the invention.
The invention provides a method for sampling respiratory droplets, the method comprising contacting with respiratory droplets a material capable of adsorbing or absorbing the contents of the respiratory droplets, recovering the contents of the respiratory droplets from the material, and analyzing the recovered contents of the respiratory droplets. The respiratory droplets may be adsorbed or absorbed from one or more of the group consisting of moisture, exhaled air, circulating air, and ambient air. The material capable of adsorbing or absorbing respiratory droplets may be a hygroscopic material. Advantageously the hygroscopic material is capable of adsorbing respiratory droplets and the contents of the respiratory droplets may be recovered by elution. Elution may be accomplished with an aqueous buffer.
The invention provides articles, devices, and methods for sampling respiratory droplets, the article comprising a material capable of adsorbing or absorbing respiratory droplets such that the contents of said respiratory droplets can be recovered. Because the droplets can be adsorbed or absorbed such that the contents of the droplets can be recovered, the contents of the droplets can then be analyzed, for example for the presence of and/or to identify microbes such as viral particles.
Advantageously, the invention has the ability to accumulate respiratory droplets from any source, for example, moisture, such as from saliva or exhaled air, circulating air, and ambient air for any duration of time that the invention is employed, leading to increased sampling of infectious agents over time. This contrasts with the most common sampling methods which only provide samples for infectious agent analysis obtained at a single time point.
Additionally, the articles and methods of the present invention may directly sample droplets from exhaled breath (exhalant) from the respiratory tract, which are the direct biological material responsible for the transmission of respiratory infectious agents between individuals. In contrast, sampling methods that collect different biological material, while possibly containing the infectious agent, only serve as indirect surrogates of the capacity of an individual to infect those in their immediate surroundings and/or the create a broader environmental hazard from aerosolized droplet persistence in the general vicinity. Thus, a key feature and advantage of the present invention is that it provides articles and methods to measure how infectious an individual will be to those in their immediate surroundings.
The length of time over which the invention is applied and/or the length of time that source of droplets to be analyzed is in contact with the article or device of the invention is a variable aspect of the invention, and can be varied to modulate the amount of infectious agent collected so as to accommodate different biologic characteristics of an infectious agent and thereby modulate the sensitivity and specificity of the downstream analytic method used to identify the infectious agent. For example, the sensitivity of a given analytic method can be increased by increasing the amount of time the article is in contact with the source of droplets to be analyzed, leading to increased accumulation of the infectious agent and an opportunity to both detect the presence of the agent and/or to determine the rate and quantity of the infectious agent in the source of the droplets over time. In aspects of the invention, the length of time over which the source of droplets is in contact with the articles or devices of the present invention (for example as incorporated into a naso/oral facial covering, a breath collection tube, or present without being incorporated into a device or specific container) may be varied.
The adsorbent or adsorbent material used in the article or devices of the invention can be any known material capable of collecting respiratory droplets. Advantageously, the material may be a material that collects moisture directly from air and respiratory droplets in the air can collected and the contents of the respiratory droplets can then be recovered, for example by elution, for analysis. For example, the material may comprise silica gel, a cellulose-based absorbent such as corn husk, polymeric foam, sodium polyacrylate, sodium alginate, hyaluronic acid, or other water-absorbing hydrogels.
Silica gel is an amorphous and porous form of silicon dioxide (silica), consisting of an irregular tridimensional framework of alternating silicon and oxygen atoms with nanometer-scale voids and pores. The voids may contain water or some other liquids, or may be filled by gas or vacuum.
A polymeric foam is a foam, in liquid or solidified form, formed from polymers. Examples include: Ethylene-vinyl acetate (EVA) foam, the copolymers of ethylene and vinyl acetate; also referred to as polyethylene-vinyl acetate (PEVA) Low-density polyethylene (LDPE) foam, first grade of polyethylene (PE)
Sodium polyacrylate is a sodium salt of polyacrylic acid with the chemical formula [—CH2-CH(CO2Na)-]n.
Sodium alginate is derived from brown algae or seaweed and forms heat stable gels in the presence of calcium.
The invention may further comprise infectious agent specific molecules, for example antibodies and aptamers that bind to constituents of the infectious particle, including nucleic acids, cell membranes, and intracellular structural proteins and/or intracellular contents, whether from intact or degenerating infectious agent or released from intact or degenerating infectious agent. The invention may comprise hybrid capture probes to bind the target pathogen's DNA or RNA. Proteins, antibodies, and any other known molecule may be used in the article to bind targets. The target may be a viral capsid protein.
Advantageously, the invention may further comprise an indicator of moisture absorption, for example a colorimetric indicator. The colorimetric indicator may comprise any known colorimetric assay, for example the colorimetric indicator may be methyl violet and may be in silica gels, thereby leading the gels to turn from orange, when dry, to green when hydrated. The colorimetric indicator may be provided together with the material capable of adsorbing or absorbing respiratory droplets. The colorimetric indicator may be provided separately from the material capable of adsorbing or absorbing respiratory droplets.
The article may also be free standing. For example, the article may lay flat on a surface and collect respiratory droplets from ambient or circulating air that comes in contact with the surface. An individual may also hold the article up to their face and exhale into the article. In aspects of the invention, the article may comprise a handle that allows the user to hold the article in place to make contact with exhaled respiratory droplets. The handle may allow the user to hold the article at variable distances and lengths of time from the nose or mouth. The article may comprise a “tea-bag” shape, with the material incorporated into the pouch shape of the tea bag. For example, the “tea-bag” article may comprise food-grade mesh bags, for example nylon tea bags. The “tea-bag” article may comprise a string for the user to hold the article and exhale onto the pouch shape of the tea bag. The “tea-bag” article may be affixed to clothing of the user, for example affixed by a pin and worn like a badge by the user. The “tea-bag” article may comprise colorimetric beads that change color to indicate when the “tea-bag” is saturated with moisture.
The article may come in a package together with instructions that instruct the user as to the distance at which to hold the article in place. The article may come in a package together with instructions that instruct the user as to the length of time for which to hold the article in place. The “tea-bag” article may be shipped for analysis dry, or may be packaged together with an extraction buffer or stabilizing buffer, for example in a sealed vial. The “tea-bag article” may be being placed on the inner surface of a facial covering, for example a surgical mask.
The collector tube 605 can be used for oral sampling methods and/or nasal sampling methods. The tube may be placed either in the mouth and/or nostrils and exhaled air is delivered into the collector tube that allows the exhalant to contact material that absorbs or adsorbs respiratory droplets and the contents of the respiratory droplets as the exhalant passes through the collector tube and out the collector tube exit port. The material may or may not be removed from the device prior to analyzing the sample. The collector tube may be mechanically fixed to the patient's oral or nasal cavity, for example with a cannula or by medical tape, or may be held in place by the user or a third party.
The mouthpiece 703 may be configured to be removable from the collector tube 701. The mouthpiece 703 may attach to the collector tube by any known means. For example, the mouthpiece may attach and detach from the collector tube through a screw type assembly or an air-tight fitted assembly. The mouthpiece 703 may be shaped to improve oral collection, for example, the mouthpiece may be flanged.
Hand-held aspects of the invention may be held in front of the mouth by the user similar to a lollipop or “blow pop”, which may be advantageous for testing of children. The article may further be configured to comprise a bead 1621. Once exposed to or saturated with moisture, the bead 1621 may change color to indicate saturation.
The article may come in a package together with instructions that instruct the user as to the distance at which to hold the article in place. The article may come in a package together with instructions that instruct the user as to the length of time for which to hold the article in place. The “tea-bag” article may be shipped for analysis dry, or may be packaged together with an extraction buffer or stabilizing buffer, for example in a sealed vial. The tea-bag size may be about 2×2.4 inches or about 2×2 inches, which advantageously lends itself to being capable of being placed on the inner surface of a facial covering, for example a surgical mask.
Aspects of the invention may comprise a mesh at the point of contact between the device and exhaled air. The mesh may comprise beads. Beads are preferably greater than 0.75 mm in diameter in order to not significantly impede breath. The mesh advantageously serves to protect the user from inhaling the material or the material from otherwise escaping the device while still allowing air to pass through the device, The mesh can be welded, for example ultrasonically welded, or otherwise adhered to the device. The mesh may be shaped to snap-fit onto one or more ends of the device. The mesh and beads comprising the mesh may be commercially available. The mesh and other aspects of the device may be sterilized, for example using UV sterilized or chemically sterilized. Aspects that require contact with the mouth or nose of the subject advantageously may be sterilized using a process that avoids imparting a taste on the device.
The article may also be shaped to filter circulating air. For example, the article may be shaped to filter air in an air purification system or an air conditioning system, such as a humidifier, dehumidifier, air exchanger, air cleaner, or HVAC system. The article may be shaped to filter air passing through a vent.
Heating, ventilation, and/or air conditioning (HVAC) systems control the temperature within a building or other structure. HVAC systems may include boiler systems, radiant heating systems, electric heating systems, a system of ductwork and air vents, and one or more HVAC controllers. The one or more HVAC components may include a furnace, a heat pump, an electric heat pump, a geothermal heat pump, an electric heating unit, an air conditioning unit, a humidifier, a dehumidifier, an air exchanger, an air cleaner, and/or the like. HVAC systems typically include an air filter to help remove dust and other pollutants from within the building and to protect the HVAC equipment from dust buildup which may negatively impact system performance. The article of the present invention may be provided as a filter for an HVAC system, or may be provided as part of an existing filter for an HVAC system. HVAC systems are described in U.S. Pat. No. 10,119,718, herein incorporated by reference in its entirety.
The invention also provides methods of analyzing the presence of microbes, such as viral particles using the articles and devices of the invention. The method may analyze respiratory droplets by passing air through the article comprising an absorbent or adsorbent material, wherein the material collects respiratory droplets in the air, recovering the contents of the droplets from the material, and analyzing the contents of the droplets.
Advantageously, articles, devices, and methods of the present invention allow for the contents of respiratory droplets to be recovered from the article after collection to be further analyzed. The method of recovery in the case of an adsorbent material may elution, for example by the addition of an aqueous buffer, for example but not limited to saline or phosphate-buffered saline, onto the adsorbent material. For some absorbent materials, addition of an aqueous buffer may suffice to extract the droplets. For most absorbent materials, additional treatment will be required to recover the contents of the respiratory droplets. These treatments will vary depending on the characteristics of the absorbent material used, and could include for example centrifugation, temperature modulation, or the addition of solvents or other chemicals or molecules that serve to liberate the absorbed droplets from the absorbent material. Upon recovery, the droplets will be coalesced into an aqueous phase for subsequent analysis.
Analyses of the contents of the respiratory droplets may comprise any known method of analysis, for example any method for detecting the presence of identity of a virus. The analysis may be used to detect any target analyte. The target analyte refers to the substance in the sample that will be captured and isolated. The target analyte may be inorganic (e.g., a metal, a cyanide or cyanate, a salt, etc.) or organic chemicals, macromolecules (chitin, peptidoglycan, carbohydrates, proteins, nucleic acids, lipids, etc.,), bacteria, fungi, a cell (such as a cancer cell, a white blood cell a virally infected cell, or a fetal cell circulating in maternal circulation), a virus, a nucleic acid (e.g., DNA or RNA), a receptor, a ligand, a hormone, a drug, a chemical substance, or any molecule known in the art. In preferred aspects of the invention, the analyte is not a volatile organic compound.
For example, the analysis may comprise DNA or RNA amplification, such as PCR, nucleic acid sequencing, such as next generation sequencing (NGS) and/or droplet-based sequencing, anti-body based analysis, an immunoassay, or any combination of analytic techniques and methods.
Nucleic acid template molecules (e.g., DNA or RNA) can be isolated from a biological sample in the respiratory droplet containing a variety of other components, such as proteins, lipids, and non-template nucleic acids. Nucleic acid template molecules can be obtained from any cellular material, obtained from animal, plant, bacterium, fungus, or any other cellular organism. Biological samples for use in the present invention also include viral particles or preparations. Nucleic acid template molecules can also be isolated from cultured cells, such as a primary cell culture or cell line. The cells or tissues from which template nucleic acids are obtained can be infected with a virus or other intracellular pathogen. A sample can also be total RNA extracted from a biological specimen, a cDNA library, viral, or genomic DNA. A sample may also be isolated DNA from a non-cellular origin, e.g. amplified/isolated DNA from the freezer.
Generally, nucleic acid can be extracted, isolated, amplified, or analyzed by a variety of techniques such as those described by Green and Sambrook, Molecular Cloning: A Laboratory Manual (Fourth Edition), Cold Spring Harbor Laboratory Press, Woodbury, N.Y. 2,028 pages (2012); or as described in U.S. Pat. Nos. 7,957,913; 7,776,616; 5,234,809; U.S. Pub. 2010/0285578; and U.S. Pub. 2002/0190663.
Nucleic acid from a sample may optionally be fragmented or sheared to a desired length, using a variety of mechanical, chemical, and/or enzymatic methods. DNA may be randomly sheared via sonication using, for example, an ultrasonicator sold by Covaris (Woburn, Mass.), brief exposure to a DNase, or using a mixture of one or more restriction enzymes, or a transposase or nicking enzyme. RNA may be fragmented by brief exposure to an RNase, heat plus magnesium, or by shearing. The RNA may be converted to cDNA. If fragmentation is employed, the RNA may be converted to cDNA before or after fragmentation. Generally, individual nucleic acid template molecules can be from about 2 kb bases to about 40 kb, Nucleic acid molecules may be single-stranded, double-stranded, or double stranded with single-stranded regions (for example, stem- and loop-structures).
A biological sample may be lysed, homogenized, or fractionated in the presence of a detergent or surfactant as needed. Suitable detergents may include an ionic detergent (e.g., sodium dodecyl sulfate or N-lauroylsarcosine) or a nonionic detergent (such as the polysorbate 80 sold under the trademark TWEEN by Uniqema Americas (Paterson, N.J.) or C14H22O(C2H4)n, known as TRITON X-100).
A target may be analyzed by a multitude of existing technologies, such as nuclear magnetic resonance (NMR), miniature NMR Polymerase Chain Reaction (PCR), mass spectrometry, fluorescent labeling and visualization using microscopic observation, fluorescent in situ hybridization (FISH), growth-based antibiotic sensitivity tests, and variety of other methods that may be conducted with purified target without significant contamination from other sample components. Analysis using NMR is described in U.S. Pub. 2011/0262925, herein incorporated by reference in its entirety.
PCR may be used as described or any other amplification reaction may be performed. Amplification refers to production of additional copies of a nucleic acid sequence and is generally carried out using polymerase chain reaction (PCR) or other technologies known in the art. The amplification reaction may be any amplification reaction known in the art that amplifies nucleic acid molecules such as PCR (e.g., nested PCR, PCR-single strand conformation polymorphism, ligase chain reaction, strand displacement amplification and restriction fragments length polymorphism, transcription based amplification system, rolling circle amplification, and hyper-branched rolling circle amplification, quantitative PCR, quantitative fluorescent PCR (QF-PCR), multiplex fluorescent PCR (MF-PCR), real time PCR (RTPCR), restriction fragment length polymorphism PCR). See U.S. Pat. Nos. 5,242,794; 5,494,810; 4,988,617; 6,582,938; 4,683,195; and 4,683,202, hereby incorporated by reference. Primers for PCR, sequencing, and other methods can be prepared by cloning, direct chemical synthesis, and other methods known in the art. Primers can also be obtained from commercial sources such as Eurofins MWG Operon (Huntsville, Ala.) or Life Technologies (Carlsbad, Calif.).
Alternatively, an isothermal method of amplification, e.g. rolling circle amplification (RCA) or loop-mediated isothermal amplification (LAMP), may be performed.
Amplification adapters may be attached to the fragmented nucleic acid. Adapters may be commercially obtained, such as from Integrated DNA Technologies (Coralville, Iowa). The adapter sequences may be attached to the template nucleic acid molecule with an enzyme. The enzyme may be a ligase or a polymerase. The ligase may be any enzyme capable of ligating an oligonucleotide (RNA or DNA) to the template nucleic acid molecule. Suitable ligases include T4 DNA ligase and T4 RNA ligase, available commercially from New England Biolabs (Ipswich, Mass.). Methods for using ligases are well known in the art. The polymerase may be any enzyme capable of adding nucleotides to the 3′ and the 5′ terminus of template nucleic acid molecules.
Analysis may also involve attaching the bar code sequences to the template nucleic acids e.g., for barcode PCR. A bar code may be attached to each fragment. A plurality of bar codes, e.g., two bar codes, may be attached to each fragment. A bar code sequence generally includes certain features that make the sequence useful in sequencing reactions. For example the bar code sequences are designed to have minimal or no homo-polymer regions, i.e., 2 or more of the same base in a row such as AA or CCC, within the bar code sequence. The bar code sequences are also designed so that they are at least one edit distance away from the base addition order when performing base-by-base sequencing, ensuring that the first and last base do not match the expected bases of the sequence.
The bar code sequences are designed such that each sequence is correlated to a particular portion of nucleic acid, allowing sequence reads to be correlated back to the portion from which they came. Methods of designing sets of bar code sequences are shown for example in U.S. Pat. No. 6,235,475, the contents of which are incorporated by reference herein in their entirety. Since the bar code sequence is sequenced along with the template nucleic acid, the oligonucleotide length should be of minimal length so as to permit the longest read from the template nucleic acid attached. Generally, the bar code sequences are spaced from the template nucleic acid molecule by at least one base (minimizes homo-polymeric combinations). The bar code sequences are attached to the template nucleic acid molecule, e.g., with an enzyme. The enzyme may be a ligase or a polymerase, as discussed below. Attaching bar code sequences to nucleic acid templates is shown in U.S. Pub. 2008/0081330 and U.S. Pub. 2011/0301042, the contents of which are incorporated by reference herein in its entirety. Methods for designing sets of bar code sequences and other methods for attaching bar code sequences are shown in U.S. Pat. Nos. 7,544,473; 7,537,897; 7,393,665; 6,352,828; 6,172,218; 6,172,214; 6,150,516; 6,138,077; 5,863,722; 5,846,719; 5,695,934; and 5,604,097, each incorporated by reference.
After any processing steps (e.g., obtaining, isolating, fragmenting, amplification, or barcoding), nucleic acid can be sequenced.
Sequencing may be by any method known in the art. DNA sequencing techniques include classic dideoxy sequencing reactions (Sanger method) using labeled terminators or primers and gel separation in slab or capillary, sequencing by synthesis using reversibly terminated labeled nucleotides, pyrosequencing, 454 sequencing, Illumina/Solexa sequencing, allele specific hybridization to a library of labeled oligonucleotide probes, sequencing by synthesis using allele specific hybridization to a library of labeled clones that is followed by ligation, real time monitoring of the incorporation of labeled nucleotides during a polymerization step, polony sequencing, and SOLiD sequencing. Sequencing of separated molecules has more recently been demonstrated by sequential or single extension reactions using polymerases or ligases as well as by single or sequential differential hybridizations with libraries of probes.
An advantage of the current invention is its ability to collect the respiratory material in a manner that enables subsequent assessment of active infectious particles in the material. Thus, when respiratory droplets are sampled using the articles and methods described herein, the recovered material may be analyzed functionally for the presence of active virus or bacterial particles. For example, active virus can be assessed by placing the recovered material onto cells in culture to determine if the virus in the recovered respiratory material is capable of self-propagation. Active bacteria can be assessed, for example, by placing the recovered material onto agar plates infused with the appropriate growth medium. Viable infectious agents may be assessed quantitatively or qualitatively using any number of methods known to those versed in the art. This contrasts with other methods for harvesting respiratory droplets, which often compromise the viability of any active infectious particles present in the droplets.
Articles of the invention comprising silica gel beads were tested for their absorption and adsorption of moisture.
Results for surgical masks with a nylon mesh teabag embodiment are shown to the left. Silica gel beads of a size range between 0.2-0.4 mm (200-400 um), with a methyl violet colorimetric indicator of hydration, were enclosed within a nylon mesh teabag embodiment, and the teabag affixed to the interior of a standard surgical face mask so that it was positioned between the mask and the mouth. Subjects were asked to breathe as they would normally for either 6 or 12 minutes as shown. Recovery of vapor from the breath was quantified as bead saturation, based on the colorimetric change.
Results for blow tube form embodiments are shown to the right. Silica gel beads with the same characteristics as above were placed inside a 4-inch-long tube with a diameter of 1 inch. The tube at one end has a removable cap, through which the subject blows, and a nylon mesh covering the other end of the tube through which the exhalant exits, allowing for air and vapors from the exhalant to flow freely through the tube while retaining the silica gel beads within the tube. The cap was removed, and subjects were asked to exhale into the tube for the indicated number of breaths. Subsequently the silica gel beads were analyzed for the recovery of vapor from the exhalant, quantified as bead saturation based on the colorimetric change. Positive control was 350 mg of silica gel beads incubated with 400 ul of 0.9% saline, while negative controls were untreated silica gel beads.
References and citations to other documents, such as patents, patent applications, patent publications, journals, books, papers, web contents, have been made throughout this disclosure. All such documents are hereby incorporated herein by reference in their entirety for all purposes.
Various modifications of the invention and many further embodiments thereof, in addition to those shown and described herein, will become apparent to those skilled in the art from the full contents of this document, including references to the scientific and patent literature cited herein. The subject matter herein contains important information, exemplification and guidance that can be adapted to the practice of this invention in its various embodiments and equivalents thereof
| Number | Date | Country | |
|---|---|---|---|
| 63072828 | Aug 2020 | US |
