This invention relates to point of care diagnostics, and more particularly to devices and methods for sample preparation.
Methods of detecting specific nucleic acids are of ever-increasing importance in the fields of molecular biology, diagnostics, and medicine. There currently exist several methods for detecting and identifying nucleic acids within biological samples. The reasons for selecting one method over another are varied, and include, among others, the cost or availability of reagents or equipment, the transportability and storage of the reagents or equipment, the desire to minimize the time spent or the number of steps, the accuracy or sensitivity for a certain application, the case of analysis, the ability to automate the process, and the number of nucleic acids to be simultaneously targeted.
There are multiple applications for the detection of nucleic acids in the art, and new applications are always being developed. The ability to detect and quantify nucleic acids is useful in detecting and identifying organisms or pathogens, in determining gene expression levels in organisms, or in determining the levels of small RNAs, such as small interfering RNAs (siRNAs), and thus affects many fields, including human and veterinary medicine, food processing, and environmental testing.
Laboratory-based nucleic acid detection techniques typically require one or more steps to prepare a sample to be analyzed. Sample preparation can include a method to cause cells to rupture (sample homogenization) and to break the nucleic acid into shortened lengths (fragmentation) desired for detection. To achieve repeatable test results, it is desirable to use fragmentation methods that result in statistically uniform sizes within a controllable tolerance that can be used for quantitative analysis. Homogenization and fragmentation steps are typically performed manually, and as entire separate steps from the subsequent nucleic acid detection assay.
In some cases, such as during an epidemic, pandemic, or in a war zone, it can be important to perform nucleic acid detection immediately and/or at the site of sample collection. However, it can be difficult to perform sample preparation methods at these points of care because they require trained laboratory personnel and specialized equipment, which may not be available.
Point of care nucleic acid detection would benefit from integration of sample preparation steps. This invention describes a method and practical implementations of devices which accomplish automated and integrated sample homogenization and nucleic acid fragmentation. The ability to perform sample preparation in the same cartridge as nucleic acid detection allows for automation that could save time and facilitate use by medical staff of all experience levels. The devices described herein are compact, portable, and able to provide sample-in/answer-out, affordable, point of care (POC) testing in a variety of medical facilities including but not limited to healthcare practitioner offices, emergency rooms, urgent care centers, pharmacy clinics, and in the field (for example, disaster zones, conflict zones, refugee camps, outbreak zones, and/or remote areas with limited access to a centralized healthcare system).
Integrated cartridges for sample homogenization, nucleic acid fragmentation, and nucleic acid detection include a main housing having a sample well and a detection chamber. The integrated cartridges further include a sonication feature coupled to and extending outwardly from the main housing. The sonication feature includes a sonication chamber for receiving a sample fluid. A fluidic path directs the sample fluid from the sample well, to the sonication chamber, and to the detection chamber. In some embodiments, the main housing moves the sample fluid through the integrated cartridge (which can contain, for example, from about 1 mL to about 200 mL of fluid). In some embodiments, the integrated cartridge is configured to be inserted into a nucleic acid detection reader.
The sonication feature of the integrated cartridge can be coupled to a sonotrode. The extension of the sonication feature outwardly from the main housing of the cartridge spaces the sonotrode from the main housing to limit coupling ultrasonic energy to the main housing. In some embodiments, the sonication feature includes a sonication conduit, and the sonication chamber is the channel of the sonication conduit. The sonication conduit can be formed of metal, for example. In some embodiments, the sonication feature comprises at least one sonication container, and the sonication chamber is the inside of the sonication container. The sonication container can be formed of a polymer, for example. In some embodiments, inert beads are housed within the sonication container or conduit.
In some embodiments, the sonication feature receives an ultrasound coupling fluid. The sonication feature may include a coupling fluid well for receiving the ultrasound coupling fluid. The coupling fluid (and/or the coupling fluid well) at least partially surrounds the sonication conduit or the sonication container of the sonication feature.
In some embodiments, the sonication feature includes a coupling for connection to the main housing. The coupling can include a chamber entrance that receives an unhomogenized sample fluid from the main housing and a chamber exit that delivers sonicated sample fluid back to the main housing. The chamber entrance and chamber exit are located within the fluidic path that extends through the main housing and the sonication feature. The sonication feature can also include a vent tube for equalizing pressure within the sonication feature. The vent tube can be part of the coupling between the sonication feature and the main housing. In some embodiments, the vent tube includes a filter.
In some embodiments, the sonication feature is monitored by a temperature sensor. A system can include a processor in communication with the temperature sensor, a cooling mechanism, and a heating mechanism. The processor monitors readings from the temperature sensor and executes computer readable instructions to cool the sonication feature via the cooling mechanism if a reading from the temperature sensor falls above a predetermined value, and to heat the sonication feature via the heating mechanism if a reading from the temperature sensor falls below a predetermined value. In some embodiments, the cooling mechanism cools a coupling fluid and the heating mechanism heats a coupling fluid. In some embodiments, the cooling mechanism moves cooled air over the sonication feature, and the heating mechanism moves heated air over the sonication feature.
Some embodiments include a sonotrode that defines an opening for positioning the sonication feature. The opening can be configured to at least partially surround the sonication conduit (or the sonication container). In some embodiments, the opening can be a well configured to contain a coupling fluid. In some embodiments, the sonotrode is coupled to, or monitored by, a reader that monitors and controls the temperature of the sonotrode in response to readings from a temperature sensor located within the reader or on the surface of the sonotrode.
Methods of performing sample homogenization, nucleic acid fragmentation, and nucleic acid detection using an integrated cartridge include: moving a sample fluid from the sample well to the sonication feature; transmitting ultrasonic energy into the sample fluid; moving the sample fluid from the sonication feature to the detection chamber; and performing a nucleic acid detection assay within the detection chamber. Some methods include regulating the temperature of sample fluid within the sonication feature (for example, by heating or cooling a coupling fluid surrounding the sample fluid). Some methods include dissipating ultrasonic energy using inert beads housed within the sonication chamber. Some methods include inserting the sonication feature into a sonotrode. In some embodiments, transmission of ultrasonic energy into the sample fluid occurs as the sample fluid moves continuously through the sonication feature. In some embodiments, sample fluid is subjected to ultrasonic energy in bulk volumes which are then routed from the sonication feature to the detection chamber.
The device is explained in even greater detail in the following drawings. The drawings are merely exemplary and certain features may be used singularly or in combination with other features. The drawings are not necessarily drawn to scale.
The following description of certain examples of the inventive concepts should not be used to limit the scope of the claims. Other examples, features, aspects, embodiments, and advantages will become apparent to those skilled in the art from the following description. As will be realized, the device and/or methods are capable of other different and obvious aspects, all without departing from the spirit of the inventive concepts. Accordingly, the drawings and descriptions should be regarded as illustrative in nature and not restrictive.
For purposes of this description, certain aspects, advantages, and novel features of the embodiments of this disclosure are described herein. The described methods, systems, and apparatus should not be construed as limiting in any way. Instead, the present disclosure is directed toward all novel and nonobvious features and aspects of the various disclosed embodiments, alone and in various combinations and sub-combinations with one another. The disclosed methods, systems, and apparatus are not limited to any specific aspect, feature, or combination thereof, nor do the disclosed methods, systems, and apparatus require that any one or more specific advantages be present or problems be solved.
Features, integers, characteristics, compounds, chemical moieties, or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract, and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract, and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.
Throughout this application, various publications and patent applications are referenced. The disclosures of these publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art to which this disclosure pertains. However, it should be appreciated that any patent, publication, or other disclosure material, in whole or in part, that is said to be incorporated by reference herein is incorporated herein only to the extent that the incorporated material does not conflict with existing definitions, statements, or other disclosure material set forth in this disclosure. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material.
As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. The terms “about” and “approximately” are defined as being “close to” as understood by one of ordinary skill in the art. In one non-limiting embodiment the terms are defined to be within 10%. In another non-limiting embodiment, the terms are defined to be within 5%. In still another non-limiting embodiment, the terms are defined to be within 1%.
“Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.
The terms “coupled,” “connected,” and the like as used herein mean the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another.
Throughout the description and claims of this specification, the word “comprise” and variations of the word, such as “comprising” and “comprises,” means “including but not limited to,” and is not intended to exclude, for example, other additives, components, integers or steps. “Exemplary” means “an example of” and is not intended to convey an indication of a preferred or ideal aspect. “Such as” is not used in a restrictive sense, but for explanatory purposes.
The term “sample” refers to a tissue (e.g., tissue biopsy), organ, cell (including a cell maintained in culture), cell lysate (or lysate fraction), biomolecule derived from a cell or cellular material (e.g. a polypeptide or nucleic acid), or body fluid from a subject. Non-limiting examples of body fluids include blood, urine, plasma, serum, tears, lymph, bile, cerebrospinal fluid, interstitial fluid, aqueous or vitreous humor, colostrum, sputum, amniotic fluid, saliva, anal and vaginal secretions, perspiration, semen, transudate, exudate, and synovial fluid. A sample will include nucleic acids.
Homogenization is a process whereby different fractions of a sample become equal in composition. A homogenized sample is equal in composition throughout, so that removing a fraction does not alter the overall molecular make-up of the sample remaining and is identical to the fraction removed.
Sonication is the act of applying sound or ultrasound energy to agitate particles in a sample. In biological applications, sonication can be used to homogenize a sample, disrupt cellular membranes (cell lysis), release cellular contents, and fragment nucleic acid molecules. The nucleic acid molecules subjected to sonication are sheared into smaller fragments (fragmentation).
Sonotrodes, also known as ultrasonic horns or ultrasonic probes, are devices configured to emit ultrasonic waves in order to apply vibrational energy to a sample. A sonotrode can include, for example, a stack of piezoelectric transducers attached to a tapering rod. The end of the rod is applied to the sample or to an intermediate material that couples the ultrasonic energy to the sample. The entire sonotrode acts as a resonator, vibrating lengthwise with standing waves at its resonant frequency. Frequencies typically used with ultrasonic sonotrodes range from about 20 kHz to about 70 kHz, and the amplitude of the vibration typically ranges from about 13 micrometers to about 130 micrometers. Sonotrode rods can be made of, for example, titanium, aluminum or steel, with or without heat treatment. The shape of the end of the sonotrode rod (for example, round, square, cylindrical, with or without teeth, profiled) can be optimized for the needs of a particular application and affects the characteristics of vibratory energy released.
The term “nucleic acid” refers to a natural or synthetic molecule comprising a single nucleotide or two or more nucleotides linked by a phosphate group at the 3′ position of one nucleotide to the 5′ end of another nucleotide. The nucleic acid is not limited by length, and thus the nucleic acid can include deoxyribonucleic acid (DNA) or ribonucleic acid (RNA).
The methods disclosed herein utilize sonication to homogenize and fragment the nucleic acid of a sample in preparation for nucleic acid detection. The devices disclosed herein provide a closed loop fluidics path for the sample. The invention facilitates integration of the homogenization and nucleic acid fragmentation into a cartridge or point of care device which performs any of a number of additional sample preparation steps and analysis steps. Such a point of care device could also be utilized to perform nucleic acid detection methods and target sensitivity testing methods such as those described in International Application No. PCT/US2017/037806 (Published as International Publication No. WO 2017/218858) and in International Application No. PCT/US2020/013996, each of which is incorporated by reference in its entirety.
The sample travels from the filter stack 17 to the sonication feature 5 and enters sonication chamber, or sonication channel 11, for homogenization and fragmentation. A sonication chamber or channel can be any closed feature capable of containing sample fluid during homogenization and fragmentation. In the embodiment shown in
The cartridge is configured to be inserted into a nucleic acid detection reader. The size of the cartridge can be scaled up or down, but will be small enough to be portable, shippable, inexpensive and disposable. Typically, an integrated cartridge 1 is configured to contain from about 1 mL to about 200 mL of sample fluid. As a non-limiting example, the integrated cartridge 1 shown in
The sample is homogenized and fragmented within the sonication channel 11 of the sonication feature 5. As shown in
An example sonotrode configuration is shown in
Transmission of ultrasonic energy can cause heating of the sample fluid within the sonication feature. This can make detection of nucleic acids more difficult, can alter concentrations of sample within the sample fluid, and/or can desiccate the sample fluid altogether. It can be advantageous, therefore, to regulate the temperature of the sonication feature to preserve the sample and maintain a consistent sample concentration. In some embodiments, the sonication feature can include a temperature sensor. Alternatively, the sonication feature can include one or more monitoring features that allow it to be read by a temperature sensor located within a reader 150 such as the one shown in
In some embodiments, inert beads can be housed within the sonication container 314 to increase fragmentation during sonication. For example, the beads can be zirconium beads.
Sonication containers 314 can be formed of inexpensive molded or formed materials, such as, but not limited to, polymers. Temperature regulation systems similar to those described above can be included to maintain a consistent temperature of a sample fluid inside sonication chamber 314. For example, temperature control can be accomplished by cooling or heating a coupling fluid in a well attached to the main housing 303 and surrounding the sonication container 314. Alternatively, heating and cooling can be accomplished via flow of heated or cooled air around the sonication container 314. In another embodiment, such as the one shown in
As described briefly above, methods of performing sample homogenization, nucleic acid fragmentation, and nucleic acid detection include; moving a sample fluid from the sample well, such as sample well 7 shown in
While the invention has been described with reference to particular embodiments and implementations, it will be understood that various changes and additional variations may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention or the inventive concept thereof. Certain aspects and features of any given embodiment may be translated to other embodiments described herein. In addition, many modifications may be made to adapt a particular situation or device to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular implementations disclosed herein, but that the invention will include all implementations falling within the scope of the appended claims.
The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The implementation was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various implementations with various modifications as are suited to the particular use contemplated.
This application is a continuation of U.S. patent application Ser. No. 16/848,306 filed Apr. 14, 2020, which claims the benefit of priority to U.S. Provisional Application No. 62/834,039, filed Apr. 15, 2019. Each of the aforementioned applications is hereby incorporated by reference in its entirety.
This invention was made, in part, with Government Support under STTR contract HDTRA1-18-C-0031. The Government has certain rights in the invention.
Number | Date | Country | |
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62834039 | Apr 2019 | US |
Number | Date | Country | |
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Parent | 16848306 | Apr 2020 | US |
Child | 18425316 | US |