Pathogen detection using aptamer molecular photonic beacons using a mobile device
11053556 ยท 2021-07-06
Inventors
Cpc classification
G06K7/10861
PHYSICS
C12Q1/6818
CHEMISTRY; METALLURGY
G16H10/60
PHYSICS
G16H40/40
PHYSICS
G16H50/30
PHYSICS
C12Q1/6818
CHEMISTRY; METALLURGY
G16H10/40
PHYSICS
International classification
G16H40/40
PHYSICS
G16H10/60
PHYSICS
G16H50/30
PHYSICS
G16H10/40
PHYSICS
G06K7/14
PHYSICS
Abstract
This disclosure pertains to a testing method for a target pathogen. The method uses biosensors with particular fluorescence characteristics, such that when the biosensor binds to a target pathogen, a fluorophore may emit light if excited. The biosensor may be an aptamer-based biosensor with a fluorophore reporter and a quencher. The excitation of the fluorophore and the detection of fluorescence may be made through the use of a flashlight source and a camera from a mobile device, such as a smartphone.
Claims
1. A method for detecting a pathogen comprising: adding a test subject sample fluid to a replaceable aptamer molecular photonic beacon test vial comprising a solution of Aptamer Molecular Photonic Beacons and a carrier liquid medium, wherein said Aptamer Molecular Photonic Beacons are selected to bind to a protein, RNA or DNA of a target pathogen and further comprise a reporter molecule and a quencher molecule, said reporter molecule being operable to receive light and emit light after binding to said target pathogen, said binding modifying a configuration of said Aptamer Molecular Photonic Beacons from a quenched configuration, where said quencher molecule is in proximity with said reporter molecule, to an emitting configuration where said quencher molecule and said reporter molecule are separated; positioning a camera and a flash light source of a mobile computing device above at least one aperture of a light proof enclosure of a testing device fixture housing; inserting said aptamer molecular photonic beacon test vial in a test vial receptacle of said testing device fixture housing; preventing ambient light from leaking inside the light proof enclosure by performing one of: using a movable gate of said light proof enclosure to cover said test vial receptacle; and using an opaque seal of said test vial to cover said test vial receptacle; using software testing application executable code on said mobile computing device having a processor to execute said code: to perform a test to detect a presence of said target pathogen by operating said flash light to illuminate said solution in said vial to excite said reporter molecule and acquiring at least one image of emission from said reporter molecule using said camera; and to at least one of: compute an infection status based on said captured image; and display said infection status on a display of said mobile computing device.
2. The method as defined in claim 1, further comprising storing at least one of said captured image and said infection status in a storage module of said mobile device.
3. The method as defined in claim 2, further comprising sending at least one of said captured image and said infection status to a remote server.
4. The method as defined in claim 1, further comprising one of receiving a user input code on said mobile computing device and scanning a barcode associated with said vial using said camera of said mobile computing device to determine at least one of the states of said replaceable test vial and a target pathogen being tested.
5. The method as defined in claim 4, further comprising using said software testing application on said mobile computing device to communicate with a remote server to validate said replaceable test vial based on one of said code and said barcode.
6. The method as defined in claim 5, further comprising preventing said mobile device from being operable to determine infection status when the state of the replaceable test vial indicates an invalid replaceable test vial.
7. The method as defined in claim 4, further comprising preventing said mobile device from being operable to determine infection status when the state of the replaceable test vial indicates an invalid replaceable test vial.
8. The method as defined in claim 1, further comprising using said software testing application on said mobile computing device to analyze said image to confirm a presence of said replaceable test vial, wherein a negative infection status test result can be prevented.
9. The method as defined in claim 8, further comprising providing a reference element to be imaged with said vial, wherein said presence is confirmed by processing said captured image to identify said reference element.
10. The method as defined in claim 1, further comprising placing a bandpass optical filter over said camera so as to have sensitivity to emission from said reporter molecule.
11. The method as defined in claim 1, wherein said acquiring comprises acquiring an image immediately following operating said flash light to illuminate said solution in said vial to excite said reporter molecule.
12. The method as defined in claim 1, wherein said at least one image of emission from said reporter molecule using said camera is analyzed to determine a severity of an infection or disease.
13. The method as defined in claim 1, further comprising inserting at least one test calibration vial in said test vial receptacle of said testing device fixture housing and using said software testing application on said mobile computing device to perform at least one calibration.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The invention will be better understood by way of the following detailed description of embodiments of the invention with reference to the appended drawings, in which:
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DETAILED DESCRIPTION
(17) Recent advances in bioscience have made it possible to detect pathogens without the complex methods being employed up to now. These Aptamers Molecular Photonic Beacons bind to specific pathogens that can in turn emit light when being bound to the target pathogen. Devices such as smartphones have the computing means to analyze the results and provide the conclusion, and store the results locally or communicate them, if so desired.
(18) Aptamers
(19) Aptamers are single stranded nucleic acid molecules or peptide molecules that fold into complex three-dimensional conformations that can selectively bind to a specific target, including proteins, peptides, carbohydrates, small molecules, toxins, and even live cells. Aptamers assume a variety of shapes due to their tendency to form helices and single-stranded loops. Aptamers can be developed to bind to any desired target. The aptamer can be generated via in-vitro selection or via SELEX (systematic evolution of ligands by exponential enrichment) ranging from metal ions to cells. On the molecular level, the aptamers will bind to its cognate target by non-covalent interactions. As such, aptamers may be specifically designed to bind to any pathogens (e.g. viruses, bacteria, spores, etc.) to help in diagnosis or to deliver drugs to specific cells inside a patient. One such aptamer has been proven to bind to SARS-CoV-2 S1 spike protein on the surface of the virus. Other Aptamers can be chosen or designed to bind to other proteins or RNA or DNA of other viruses and pathogens.
(20) Fluorophores
(21) Fluorophores are molecules that can be very small, <1200 Daltons that may be attached to one end of the aptamer. One such fluorophore that exhibits the desired properties that match the characteristics of the smartphone LED and cameras is Atto 465 (e.g. from Sigma Aldrich). As described herein, the fluorophore may be used as the reporter in an Aptamer Molecular Photonic Beacon.
(22) Quencher
(23) A quencher is also a small molecule that can be attached to the opposite end of the aptamer than the fluorophore. The quencher, while in proximity with the fluorophore, absorbs the energy from the fluorophore that would otherwise be emitted. On separation from the fluorophore, the quencher stops being operable to absorb this energy, therefore allowing the fluorophore to emit light. This separation occurs, in an appropriately designed aptamer, on binding to the target protein, RNA or DNA. One quencher that will attach and quench the Atto 465 fluorophore is the Iowa Black Fluorescence Quencher.
(24) Aptamer Molecular Photonic Beacons (AMPB)
(25) As illustrated in
(26) Aptamer Molecular photonic beacons hybridize to their specific target sequence causing the hairpin-loop structure to open and separate the reporter and the quencher. As the Quencher is no longer in proximity to the reporter, fluorescence emission may take place when the necessary excitation is provided to the molecule. Therefore, the measured fluorescence signal may be directly proportional to the amount of target pathogen. As a matter of fact, the more testing solution contains the target pathogen, the more Aptamer Molecular photonic beacons will be attached and have their reporter separated from their quencher (i.e. the fluorescence signal will be stronger). There are different 3D shapes and changes to the morphology of the Aptamer Molecular photonic beacons on binding to follow the change on binding. Similarly, the fluorophore and quencher conjugation to the aptamer may be different. In some cases, the quencher can be released.
(27) As is known in the art, the fluorophore may be selected to emit light for a particular wavelength of absorbed light.
(28) Aptamer Molecular Photonic Beacon (AMPB) Testing Device
(29) As described herein, the Applicant has discovered a method of testing for a pathogen using a mobile device and an Aptamer Molecular Photonic Beacon solution. As a matter of fact, it is possible to select an AMPB with a fluorophore excitable by the main wavelength of the light emitted by a mobile device's flash. Given the optical properties of most cameras included in current mobile devices, the camera may be operable to detect fluorescence emitted by AMPBs bound to target pathogens. In order to detect low levels of emitted fluorescence, a bandpass filter may be required. The filter may thus allow the mobile device's camera to sense a small amount of the target pathogen, such as would be present in a patient in early stages of infection while further filtering out fluorescence from water in the solution and other contaminants in the saliva such as food particles and fruit particles.
(30) In some embodiments, the bandpass filter may not be required for the system to properly function. As such, the bandpass filter may not be required when a sufficiently lightproof enclosure (i.e. no leakage of ambient light) and a fluorophore operable to emit light for a long enough period after the excitation light source has stopped are used. As a matter of fact, these may allow the testing device to flash the light source and to capture an image after the light source has been extinguished (i.e. the only light being captured would be the light emitted by the fluorophores, therefore no filter may be required).
(31) In some embodiments, there AMPB may be selected to bind with a given surface protein of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, the virus causing COVID-19) and where the quencher and the reporter are chosen to be excited by a light source having approximately 450 nm and emit at 490 nm, or appreciably similar wavelength. Someone skilled in the art will appreciate the fact that the AMPB may be selected to bind to any pathogen.
(32) In order to perform a diagnostic test to determine the infectious state of a person with regards to a target pathogen, a sample of the saliva or nasal mucus may be taken with a swab and inserted into a vial. The vial contains the AMPB and a carrier liquid medium, such that when the vial is shaken the person's saliva or nasal mucus may mix with the AMPB and carrier liquid medium.
(33) Reference is now made to
(34) In some embodiments, the slot for the mobile device 27 may be a coupler which effectively joins the mobile device to the fixture 29. For example, a relatively small fixture 29 may be positioned over a mobile device, such that it only covers an area over a camera and a flash of the mobile device. In such example, the slot for the mobile device 27 may be replaced by the connection between the mobile device and the fixture 29, which is herein defined as a coupler. The coupler may be lightproof, such that no ambient light may leak to the inside of the enclosure/fixture 29. In some embodiments, the coupler may be a mobile device cover that fits over the mobile device and holds the other parts of the testing device in the required position over the flash and camera(s).
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(36) The mobile device's 39 camera 37 may be aligned with a filter 35, which may be a notch optical filter specific to 490 nm (e.g. a bandpass filter with a narrow band around 490 nm). As the mobile device's 39 may have a flash 33 made of Light Emitting Diodes that have a fundamental light emission between 450 to 460 nm, the fluorophore may emit light at around 490 nm such that it may be the only light to pass-through the filter 35. In some embodiments, the optical filter may include a small gap to allow any light to passthrough, such that an aligned camera may sense the intensity of flash and may be able to confirm the presence of a vial inserted in the vial's receptacle. In some embodiments where the filter is not required, as described herein, the detection of the vial may be done by capturing a first image of the vial while the light source is operating. The testing may subsequently be done by operating once more the light source and thereafter capturing an image once the light source has extinguished (such that only a presence of fluorophores may be emitting). Someone skilled in the art will appreciate that it may be feasible to continuously capture a series of image, some of them being while the light source is operating (i.e. confirming the presence of the vial) and some of them after the light source has extinguished.
(37) The reporter quantum efficiency and the absorbance of the light by the liquid medium will determine the light emission quantity in number of photons. As mobile devices 39 have different of cameras and that some mobile devices may have multiple camera sensors, the testing system, through the control application, may select the camera lens with the highest quantum efficiency for the testing, this being about 75% at 490 nm. Additionally, any image processing capabilities of smartphones or other mobile devices may be used to enhance the image captured during the test. These capabilities may include post-processing software, which may include artificial intelligence image processing. This may enhance the sensitivity of the test and therefore allow for detection of the target pathogen in relatively small quantities.
(38) The sensors in the smartphone or similar device can use a single cell of the camera sensor or a plurality, or all, the cells of the sensor to calculate the results of the test performed. This maybe done immediately as part of the test process or stored over time and multiple tests and then analyzed. The fluorophore emission light can be taken from a specific region of interest within the acquired image. Spatial intensity analysis can be used to confirm that the intensity observed matches intensity from the expected distribution of the aptamer within the solution of the vial.
(39) It will be appreciated that the test result can apply a simple threshold to the total amount of light observed to give essentially a binary result, or the amount of light received can be used to qualify or quantify the result. This can allow the positive or negative result to be qualified with a confidence value that health care professionals can consult. In some tests, the amount of light in the acquired image can be used to be correlated with a disease state or disease severity.
(40) The fluorophore can have a lifetime that will permit the emission light to be captured by the mobile device's camera once the flash light source is turned off.
(41) A reflector may further be placed behind the vial to reflect any light emitted by the fluorophore back to the camera, similarly a tube can be placed between the vial and the camera to eliminate any external light from effecting the reading. A similar absence of ambient or external light maybe achieved by another means as well.
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(43) In the embodiment of
(44)
(45) In the embodiment of
(46) Now referring to
(47) For example,
(48) In its resting position, the fluorescent part 51 of the engagement and reference system may be outside of the field-of-view of the mobile device's camera(s). When a test vial is fully engaged and the engagement and reference system is in its deployed position, the fluorescent part 51 may be inside the field-of-view (FoV) of the mobile device's camera(s). The deployed position of the engagement and reference system may be positioned such that it does not interfere with the detection of AMPBs from the test vial while remaining inside the FoV of the camera(s). This may be particularly useful to ensure that no malfunction happened during a test, mostly for a negative test result.
(49) As a matter of fact, a negative test result necessarily means that no AMPBs emitted light, or that an insignificant number of AMPBs emitted light. Thus, a negative result for a test may be the detection of a completely dark testing chamber inside the testing device. Some device or mobile device application failures or malfunction may lead to similar results, such as the non-operation of the flash, an issue with the flash and/or camera controls, etc. This may mean that a false-negative result may be given to the person being tested, potentially leading to the person unknowingly spreading the disease.
(50) When equipped with an engagement and reference system such as the one described herein, the fluorescent part 51 may be present in the sensed picture. Thus, while there may be no light emitted from the test vial (i.e. negative test result), the test may be confirmed as having successfully taken place by the recording of the fluorescent part 51 being in the FoV.
(51) Someone skilled in the art will appreciate that any other configuration of an engagement and reference system may be used without departing from the teachings of this disclosure. Systems may also be used for only one of the functions of the described engagement and reference system (e.g. only for engagement of the vial or only for the reference). As such, other mechanical configurations or other systems (e.g. electrical, magnetic, etc.) may be used in lieu of the one described herein. Optical engagement and reference system may use other light sources (e.g. phosphorescent). A static reference system may be used, in which a fluorescent part 51 or equivalent is fixed at the deployed position (i.e. always in the FoV of the camera(s)).
(52) Now referring to
(53) Similarly, as the size and the positioning of the flash and camera(s) differs between mobile device models (and its position inside the mobile device slot), a replaceable aperture selector 52 may be inserted in the fixture 29 in an aperture selector slot that may be positioned between the mobile device slot and the test vial slot 25. The aperture selector 52 may include the necessary flash aperture 33 and the one or more camera apertures 37 that are associated with the mobile device to be used and inserted inside the mobile device slot. Additionally, the opening of the aperture selector slot on the fixture 29 may include an opaque seal surrounding the area.
(54) Using different mobile device adapters 50 and their associated aperture selector 52 may allow the user of the testing system to operate it with multiple different devices. This may be particularly useful for businesses in which different operators may perform the tests and may not necessarily use the same mobile device.
(55) Now referring to
(56) The testing device fixture 29 may include one or more mating apertures to reciprocate the flash light source and the camera from the mobile device 39. These apertures may be combined in one bigger aperture, such that the fixture 29 may cater to several different mobile devices 39. The one or more apertures may be surrounded by a light seal to provide a sufficient light seal between the mobile device 39 and the fixture 29, such that no light may leak inside the container and skew the results.
(57) In this embodiment, there may be three receptacles for testing vials 31, 31. While one test vial 31 may have a patient's sample to be tested, the remaining vials 31 may be calibration vials to be used either before every test or after any number of tests has been done (e.g. before the first test of the day a calibration may be required, every time the mobile device 39 is removed from the fixture 29, once every ten tests, etc.). Having the extra vial receptacles on the fixture 29 itself allows for increased efficiency when testing a significant number of patients. It further allows to ensure the calibration vials 31 remain in good condition to be used for a longer period of time.
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(60) To prevent any ambient light from degrading the test results, the fixture 29 may further include an opaque seal 41 between the fixture 29 and the mobile device 39, the seal effectively surrounding the apertures for the camera(s) 37 and the flash 33.
(61)
(62) As illustrated in the embodiment of
(63) The embodiment of
(64) Someone skilled in the art will appreciate that other means of triggering the different testing sequence may be used. For example, a test button may be included on the fixture 29 or on the fixture removable cap 36 to trigger the test. The captured image may be automatically transferred to a paired computing device to which the communication module 38 is connected to. The captured image may further be recorded on an on-board non-transitory memory unit, which may allow for subsequent transfer to a computing device.
(65) The fixture 29 may further include a power source to provide sufficient power for the operation of the light source 33, the camera 37 and the communications module 38. For example, the power source may be a rechargeable battery, which may be recharged by connecting a power cable to a port included on the fixture 29. In some embodiments, the battery may be a replaceable battery in a compartment easily accessed.
(66) Although described as communicating with a computing device to process the captured image data and assess the infection state of the tested person, it will be appreciated that the standalone testing device as presented in
(67) It will be further appreciated that any additional optics elements (i.e. filters, mirrors, lenses, etc.) may be added inside the fixture 29 or to the test vial to increase or change certain optical characteristics of the testing device and improve its efficiency at determining the infection state of a tested subject.
(68) Now referring to
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(71) In other embodiments, the barcode sticker 63 may be on the cap 57 or may be on a package containing one or more test vials. In yet another embodiment, the barcode sticker 63 may be replaced by any other means of confirming the source of the test vial, such as an RFID tag. In some embodiments, the sticker may strictly be a reflective sticker added to increase the sensitivity of the test.
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(73) The embodiment illustrated in
(74) In the embodiment of
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(76) Someone skilled in the art will appreciate that specific wavelengths disclosed herein may change with different models of mobile devices, as may the sensitivity of the method and characteristics of the fixture. As a result of such, the Aptamer Molecular Beam specifications (e.g. fluorophore and quencher used, etc.) may also change. However, whether any or all of these changes are made to the aptamer molecular photonic beacon testing device, the underlying principles are the same as taught herein.
(77) Software Application
(78) To operate the aptamer molecular photonic beacon testing device with a mobile device, a software application is required. As a matter of fact, the software application is required as the test requires control over the flash, the camera, computing power and other modules of the mobile device.
(79) Now referring to
(80) The connectivity module can establish a connection to a server associated with the provider of the test vials. The application 65 can be configured to perform a test only when the user of the application 65 enters a valid code associated with the test vials, such as by acquiring an image of a barcode or by entering a code found on the vial or its packaging. The code can be validated locally by the application 65 using conventional decryption, hash value or checksum verification, or it can be validated by the server. If the code is invalid, the test vial should not be trusted. If ever a batch of vials were to be found to be defective, the server can report to the application 65 that the vial, even with a valid code, is defective and notify the user to seek a replacement using the display module 77.
(81) The software application 65 may thus provide the processing module 67 (which may include the mobile device's processor, transitory and non-transitory memory units, etc.) with instructions which, when they are executed are operable to control the other modules of the mobile device. As such, the flash module 69 may be operated by the software application 65 to trigger at a start of a test and to last for a given timeframe. Once the flash has been operated, the software application 65 may allow the camera module 71 to capture images inside the testing device. The software application 65 may choose the camera lens with the highest quantum efficiency, which may be about 75% at 490 nm. The software application 65 may capture the amount of light emitted by the AMPBs reporters over a given capture time, which may be a fixed time or as long as the emission lasts. If the photons that are captured are above the threshold specified in the application to eliminate background optical noise in the system, the pathogen has been detected and this can be displayed or, via the communications capabilities of the mobile, transmitted. If the photons captured are below the threshold, the negative results are displayed or communicated, as required.
(82) The smartphone or other mobile device with the ability to induce a response of the AMPBs fluorophores can be programmed to capture a single event (e.g. one flash), or a series of events. Such events then can form databases where the results can be deduced by algorithms or AI that is built into the mobile device.
(83) The displaying of the results may be done through the display module 77 which the software application 65 may control to display any desired information. As described, the results may be communicated to any other system (local or through a wired or wireless connection) or online database through the mobile device's connectivity module 75. A copy of the data (test result, recorded pictures, name of the user, timestamp, barcode of the testing vial, etc.) may also be locally registered on the mobile device's storage module 73. Additionally, when no wired or wireless connections are available, the data may be stored locally before being uploaded to an online server once a connection has been established.
(84) Mobile devices may have numerous other sensors which may allow for the registration and reporting of useful data. As such, the results can contain personal information (as configured by the user or mandated by an official health organization), such as name, time, date, and GPS coordinates. This may be particularly helpful in conjunction with pandemic tracking applications. The software application 65 may thus provide an API to connect to such other apps.
(85) Someone skilled in the art will appreciate that the mobile device capabilities required to perform the functions listed herein maybe performed by other computing devices with the same capabilities as described herein.
(86) Aptamer Molecular Photonic Beacon Testing Method
(87) As described herein, the aptamer molecular photonic beacon testing device and the software application running on the mobile device may be used to perform testing against a target pathogen. The Aptamer Molecular photonic beacon may thus be specific to the target pathogen, such that it may attach to it and its reporter may emit a fluorescent response to a light source. The ability to measure the emitted fluorescence by the mobile device's camera(s) provides the means to establish the amount of virus found (viral load) inside a fluid sample from a person and thereafter to establish the strength of the infection (or the lack of infection). A sequence of tests on the same patient over days may further establish the growth and demise of the infection.
(88) Similarly this method of evaluation of the presence of the virus in any method by using the power of a mobile device or similar device can improve the acquired results and eliminate the human factor such as in PCR based tests for virus or other pathogens.
(89) Now referring to
(90) Afterwards, the tested subject may add a sample of fluid, such as saliva or nasal mucus 83 inside the vial containing the AMPBs and a carrier liquid medium. In order to properly mix the sample fluid with the AMPBs, the vial may then be shaken 85 for a predetermined amount of time. Once completed, the tester may insert the vial inside the testing device's vial slot 87. The mobile device may further be inserted in the testing device's fixture 89 and the test may be subsequently performed 91.
(91) Performing the test 91 may include triggering the flash light source for a given period of time. The image capture may thereafter be done either immediately after the flash light source has extinguished (i.e. when using certain fluorophores, they may continue to emit light for a given time even after the excitation input is removed; this may therefore be used with embodiments of the device which does not include a filter for the camera as the only light that may be captured would come from fluorophores) or may be done while the flash light source is still providing light to the test vial. In some embodiments, the testing device may proceed to a number of flash light source and image capture cycles, such as to have multiple data points that may be used in the image post-processing step.
(92) Once the test has been completed and the software application has run its analysis of the captured images, the test results may be displayed 93 on the mobile device. In some embodiments, the test results may be further communicated and/or stored locally or on a remote server.
(93) It will be recognized that this method of detecting virus and other pathogens, forming light emitting molecular photonic beacons formed from aptamers with fluorophores matched to the flash spectrum of the flash light and spectral sensitivity of the cameras, is a new and efficient means of detecting any type of virus, or parts thereof, or surface proteins, that binds to the specifically tailored sequences of the probe that is an aptamer or other biological molecular sequence. While aptamers with fluorophore reporters have been described in prior art research, its uses have generally been limited to detection by spectroscopy or using specialized tools and devices. Being able to test and detect a response from a simple mobile device, as a vast majority of the worldwide population have access to, is a significant improvement.