Patent Publication Number: US-2022214480-A1

Title: Airborne coronavirus detector and alerting system

Description:
INTRODUCTION 
     This section provides background information related to the present disclosure which is not necessarily prior art. 
     The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic has changed the way hygiene is managed and maintained in public and other shared spaces. This includes shared spaces, such as passenger compartments in vehicles. SARS-CoV-2, which causes coronavirus disease 2019 (COVID-19), and other deadly microbes can transmit through direct person-to-person contact from the uptake of contaminated airborne or aerosol droplets (e.g., airborne pathway). Such viruses enter the nasal membrane and attach to proteins (such as, angiotensin converting enzymes like angiotensin converting enzyme 2 (“ACE2”)) in humans or other animals that are embedded in cell walls. Surface coatings that render pathogens contaminating surfaces harmless, as well as surface tests are common. However, there exists a lingering need for systems and methods configured for quick detection of airborne viruses. 
     SUMMARY 
     This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
     The present disclosure relates to a detecting system that is configured to detect an airborne virus or viruses (such as, the SARS-CoV-2) and to alert the user(s) of the presence of the airborne virus or viruses. 
     In various aspects, the present disclosure provides a method for preparing a system for detecting an airborne virus. The method may include preparing a thin-film coating on one or more surfaces of a substrate; ablating the thin-film coating to form an optical grating structure; and associating a plurality of receptors having an affinity and specificity for the airborne virus with the optical grating structure so that the optical grating structure is capable of indicating the presence of the airborne virus. 
     In one aspect, the associating may include contacting a liquid medium that includes the plurality of receptors with the optical grating structure. 
     In one aspect, the substrate may be a glass substrate and the thin-film coating may be a self-aligned monolayer that includes a plurality of hydrophobic hydrocarbon tails bonded to a siloxane cross-linked backbone that is disposed parallel with the substrate. 
     In one aspect, the plurality of receptors may be respectively disposed on distal ends of the hydrocarbon tails oriented away from the substrate, so that each of the plurality of receptors is exposed to a surrounding environment. 
     In one aspect, preparing the thin-film coating may include contacting the one or more surfaces of the substrate with an organosiloxane precursor. 
     In one aspect, the receptors may be angiotensin converting enzymes having hydrophobic regions that are associated with the distal ends of hydrophobic hydrocarbon tails. 
     In one aspect, the ablating may include using a laser holographic technique. 
     In one aspect, the method may further include disposing the optical grating structure, which includes the plurality of receptors, within an optical cavity defined by two opposing reflecting surfaces. 
     In one aspect, the optical cavity may be in communication with a photocell detector that is configured to detect changes in at least one of a refractive index and a diffraction efficiency of the grating structure. 
     In one aspect, the photocell detector may be in communication with an alarm that is configured to emit a signal when a change occurs in the at least one of the refractive index and the diffraction efficiency of the grating structure. 
     In one aspect, the optical cavity may be in communication with an alarm that is configured to emit a signal when a change occurs in the at least one of a refractive index and a diffraction efficiency of the grating structure. 
     In various aspects, the present disclosure provides a system for detecting airborne viruses. The system may include an optical grating structure. The optical grating structure may include a substrate; a patterned thin-film coating on one or more surfaces of a substrate; and a plurality of receptors having an affinity and specificity for the airborne virus disposed on the patterned thin-film coating and oriented away from the substrate to be exposed to a surrounding environment. 
     In one aspect, the substrate may be a glass substrate and the thin-film coating may be a self-aligned monolayer that comprises a plurality of hydrophobic hydrocarbon tails bonded to a siloxane cross-linked backbone that is disposed parallel with the substrate. 
     In one aspect, the receptors may be angiotensin converting enzymes having hydrophobic regions that are associated with the distal ends of hydrophobic hydrocarbon tails. 
     In one aspect, the system may further include an optical component. The optical component may include an optical cavity defined by two opposing reflecting surfaces and an incident light source disposed adjacent to an exterior surface of a first reflecting surface. The optical grating structure may be disposed within the optical cavity. The incident light source may be configured to direct light towards the first reflecting surface so that light in resonance enters into the optical cavity. 
     In one aspect, the system may further include a photocell detector that is in communication with the optical cavity and configured to detect changes in at least one of a refractive index and a diffraction efficiency of the optical grating structure. 
     In one aspect, the photocell detector may be in communication with an alarm that is configured to emit a signal when a predetermined change occurs in the at least one of the refractive index and the diffraction efficiency of the optical grating structure. 
     In various aspects, a system for detecting airborne viruses in a passenger compartment of a vehicle. The system may include an optical grating structure and an optical component. The optical grating structure may include a substrate; a patterned thin-film coating on one or more surfaces of a substrate; and a plurality of receptors having an affinity and specificity for the airborne virus disposed on the patterned thin-film coating and oriented away from the substrate to be exposed to a surrounding environment. The optical component may include an optical cavity defined by two opposing reflecting surfaces and an incident light source disposed adjacent to an exterior surface of a first reflecting surface. The optical grating structure may be disposed within the optical cavity. The incident light source may be configured to direct light towards the first reflecting surface so that light in resonance enters into the optical cavity. 
     In one aspect, the substrate may a glass substrate and the thin-film coating may be a self-aligned monolayer that comprises a plurality of hydrophobic hydrocarbon tails bonded to a siloxane cross-linked backbone that is disposed parallel with the substrate. The receptors may be angiotensin converting enzymes having hydrophobic regions that are associated with the distal ends of hydrophobic hydrocarbon tails. 
     In one aspect, the system further includes a photocell detector that is in communication with the optical cavity and configured to detect changes in at least one of a refractive index and a diffraction efficiency of the optical grating structure. The photocell detector may be in communication with an alarm that is configured to emit a signal when a predetermined change occurs in the at least one of the refractive index and the diffraction efficiency of the optical grating structure. 
     Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
         FIGS. 1A and 1B  are schematics of an example airborne virus detection system in accordance with various aspects of the present disclosure; 
         FIGS. 2A and 2B  are schematics of an example of an alert system for an airborne virus detection system in accordance with various aspects of the present disclosure; 
         FIG. 3  illustrates an example method for forming a system for detecting airborne viruses in accordance with various aspects of the present disclosure; 
         FIGS. 4A-4C .  FIG. 4A  is a schematic of a thin film coating on a substrate in accordance with various aspects of the present disclosure.  FIG. 4B  is a schematic of an ablation process for forming an optical grating structure in a thin-film coating in accordance with various aspects of the present disclosure.  FIG. 4C  is a schematic of the optical grating structure illustrated in  FIG. 3A  having a plurality of receptors embedded thereon. 
     
    
    
     Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
     Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific compositions, components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail. 
     The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, elements, compositions, steps, integers, operations, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Although the open-ended term “comprising,” is to be understood as a non-restrictive term used to describe and claim various embodiments set forth herein, in certain aspects, the term may alternatively be understood to instead be a more limiting and restrictive term, such as “consisting of” or “consisting essentially of” Thus, for any given embodiment reciting compositions, materials, components, elements, features, integers, operations, and/or process steps, the present disclosure also specifically includes embodiments consisting of, or consisting essentially of, such recited compositions, materials, components, elements, features, integers, operations, and/or process steps. In the case of “consisting of,” the alternative embodiment excludes any additional compositions, materials, components, elements, features, integers, operations, and/or process steps, while in the case of “consisting essentially of,” any additional compositions, materials, components, elements, features, integers, operations, and/or process steps that materially affect the basic and novel characteristics are excluded from such an embodiment, but any compositions, materials, components, elements, features, integers, operations, and/or process steps that do not materially affect the basic and novel characteristics can be included in the embodiment. 
     Any method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed, unless otherwise indicated. 
     When a component, element, or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other component, element, or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     Although the terms first, second, third, etc. may be used herein to describe various steps, elements, components, regions, layers and/or sections, these steps, elements, components, regions, layers and/or sections should not be limited by these terms, unless otherwise indicated. These terms may be only used to distinguish one step, element, component, region, layer or section from another step, element, component, region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first step, element, component, region, layer or section discussed below could be termed a second step, element, component, region, layer or section without departing from the teachings of the example embodiments. 
     Spatially or temporally relative terms, such as “before,” “after,” “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. Spatially or temporally relative terms may be intended to encompass different orientations of the device or system in use or operation in addition to the orientation depicted in the figures. 
     Throughout this disclosure, the numerical values represent approximate measures or limits to ranges to encompass minor deviations from the given values and embodiments having about the value mentioned as well as those having exactly the value mentioned. Other than in the working examples provided at the end of the detailed description, all numerical values of parameters (e.g., of quantities or conditions) in this specification, including the appended claims, are to be understood as being modified in all instances by the term “about” whether or not “about” actually appears before the numerical value. “About” indicates that the stated numerical value allows some slight imprecision (with some approach to exactness in the value; approximately or reasonably close to the value; nearly). If the imprecision provided by “about” is not otherwise understood in the art with this ordinary meaning, then “about” as used herein indicates at least variations that may arise from ordinary methods of measuring and using such parameters. For example, “about” may comprise a variation of less than or equal to 5%, optionally less than or equal to 4%, optionally less than or equal to 3%, optionally less than or equal to 2%, optionally less than or equal to 1%, optionally less than or equal to 0.5%, and in certain aspects, optionally less than or equal to 0.1%. 
     In addition, disclosure of ranges includes disclosure of all values and further divided ranges within the entire range, including endpoints and sub-ranges given for the ranges. 
     Example embodiments will now be described more fully with reference to the accompanying drawings. 
     In various aspects, the present disclosure provides a system  100  configured to detect airborne viruses, such as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), present in a surrounding environment. In alternative aspects, it will be appreciated that such a detection system can also be employed with other airborne pathogens. As illustrated in  FIG. 1A , the system  100  includes a thin-film coating  110  disposed on one or more surfaces of a substrate  120 . The substrate  120  is preferably a thin, substantially flat surface so as to limit or avoid reflective offsets that may degrade performance. In certain instances, the substrate  120  may be transmissive to wavelengths of light generated by a light source. For example, the substrate  120  may be a high-quality glass substrate having a low thermal expansion coefficient and a high optical transmission (e.g., greater than or equal to about 60%) for wavelengths of light generated by a laser diode or other light source. In other instances, the substrate  120  may be a plastic substrate. 
     The thin-film coating  110  may be a patterned self-aligned monolayer (“SAM”) that includes a plurality of crosslinked hydrocarbon siloxane moieties, including, for example, hydrophobic hydrocarbon tails  112  bonded to a siloxane cross-linked backbone. The siloxane cross-linked backbone may be parallel with the substrate  120 , while the hydrophobic hydrocarbon tails  112  may extend from the siloxane cross-linked backbone in an ordered manner. Thus, the thin-film coating  110  may be a one molecule thick layer of material that bonds to a surface of the substrate in an ordered way. In certain instances, as illustrated, the thin-film coating  110  may have a linear pattern that includes a plurality of repeated dimensions (e.g., rows  118 ) that defines an optical grating, for example a holographic optical element (“HOE”). 
     An “optical grating structure” typically comprises one or more openings to permit certain wavelength(s) of light to pass through. For example, in certain aspects, an optical grating structure may comprise a plurality of parallel rows  118  or discrete regions spaced apart, but that are substantially parallel to one another. The spacing between adjacent rows defines a plurality of openings through which certain wavelengths of light may pass. Though not illustrated, in certain instances, the grating may also comprise a second plurality of rows having a distinct orientation from the first plurality of rows that are likewise spaced apart, but substantially parallel to one another. The first and second plurality of rows may intersect or contact one another at one or more locations to form a grid or mesh structure. 
     In certain variations, an optical grating pattern includes rows formed on a surface of the substrate that defines a period “p” (a distance defined from a side of a first row or linear feature to a side of a second adjacent row or linear feature). A distance “d” between adjacent rows is considered an opening (or aperture or slit) through which the target light wavelengths can pass. The thin-film coating  110  may have a pattern that has a grating periodicity (p) of less than or equal to about 2 μm for diffraction angles larger than about 13 degrees. The skilled artisan will appreciate that various other patterns may be formed in the thin film coating  110  to form different optical gratings. 
     The system  100  may further includes a plurality of receptors  116  disposed on distal ends  114  of the crosslinked hydrocarbon siloxane moieties. More particularly, the plurality of receptors  116  may be disposed on distal ends  114  of the hydrophobic hydrocarbon tails  112 , away from the substrate  120 . The plurality of receptors  116  have both an affinity and specificity for the targeted airborne virus, such as SARS-CoV-2. Though not illustrated, the skilled artisan will recognize that in certain instances, greater than 99%, for example, 100% coverage of the exposed distal surface  119  of each row  118  is desirable. For example, respective virus receptors  116  may be associated with or coupled to each tail  112 . In other instances, however, the desired coverage may be less than 100% (e.g., less than or equal to about 99%, less than or equal to about 95%, less than or equal to about 90%) and other design parameters may be varied accordingly, for example only, a light source input as detailed below. In each instance, the virus receptors  116  may be tailored or selected so as to have an affinity and specificity for the target airborne virus, that is for example, in the present of another virus or viruses the receptors  116  preferentially bind with the targeted virus  120 . 
     In certain variations, the receptors  116  may be angiotensin converting enzymes like angiotensin converting enzyme 2 (“ACE2”). For example, although similar to SARS-CoV, the receptor-binding domain of SARS-CoV-2 differs in several key amino acid residues to permit stronger binding affinity with human ACE2 receptors. Thus, the receptor  116  may be an ACE2 receptor having hydrophobic regions. These hydrophobic regions in the ACE2 receptor  116  may be considered to be tails, that are embedded into the hydrophobic hydrocarbon tails  112  in a manner similar to a cell wall in an animal like a human. When present, an airborne virus or viruses  120  may be associated with (e.g., bound or captured by) the receptors  116 , such as illustrated in  FIG. 1B . The association of the target virus  120  with the rows  118  in the optical grating thereby causes detectable changes in the refractive index and/or diffraction efficiency of the optical grating, as further discussed below. 
     In various aspects, the present disclosure provides a detection system  200  for alerting a user of the presence of an airborne virus or viruses, such as SARS-CoV-2, for example, by providing a signal or alarm that may be detected by a machine or human. As illustrated in  FIG. 2A , the alerting system  200  includes a sensing component  210  disposed within an optical cavity  220  defined by two opposing reflective surfaces  230 ,  240  that reflect wavelengths of light generated by a light source  250 , for example, greater than or equal to about 50% of the wavelengths of light generated by the light source  250 . As further detailed below, the two opposing reflective surfaces may include a first mirror  230  and a second mirror  240 . In certain instances, the first mirror may be a partial reflecting mirror. For example, the reflectivity of the first mirror  230  may be at least about 50%, and the reflectivity of the second mirror  240  may be about 100%, for the wavelength(s) of light  252 . In certain instances, the optical cavity  220  may have an average thickness greater than or equal to about 1 μm to less than or equal to about 10 μm. 
     The sensing component  210  may be a holographic optical element  100  such as illustrated in  FIG. 1A . For example, the sensing component  210  may include a thin-film coating  212  disposed on one or more surfaces of a substrate  216 . Though not illustrated, in certain instances, one of the first mirror  230  and the second mirror  240  may act as the substrate. 
     The thin-film coating  212  may be a patterned self-aligned monolayer that includes a plurality of crosslinked hydrocarbon siloxane moieties and plurality of virus receptors  218  disposed on distal ends of the crosslinked hydrocarbon siloxane moieties. More particularly, the plurality of receptors  218  may be disposed on distal ends of the hydrophobic hydrocarbon tails  214 , away from the substrate  216 . As illustrated, a first side of the sensing component  210  including the tails  214  and the receptors  218  may face a first side  232  of the first mirror  230 , while the substrate  216  faces the second mirror  240 . The first mirror  230  may be a partial reflecting mirror that allows a portion of light  252  generated by a light source  250  to enter the cavity  220 , while reflecting a portion of the light  252  that passes through the sensing component  210 . The portion of light  252  that passes within the optical cavity  220  is then reflected internally by the second mirror  240  to generate an optical resonator cavity (e.g., a Fabry-Perot like etalon resonator or interferometer). 
     The system  200  may further include an incident light source  250 , for example, having a wavelength in the visible spectrum, such as a blue (a wavelength in a range of about 435 nm to about 500 nm), green (a wavelength in a range of about 520 nm to about 565 nm), or red (a wavelength in a range of about 625 nm to 740 nm) laser diode or a red vertical cavity surface emitting laser (VCEL). As illustrated, the incident light source  250  may be disposed adjacent to a second side  234  of the first mirror  230  and spaced apart from the detecting component  210 . The incident light source  250  generates light  252  that is directed towards the first mirror  230 , a portion of which passes through the first mirror  230  and enters into the optical cavity  220 . Thus, the portion of light  252  that passes through the first mirror  230  into the optical cavity  220  towards the second mirror  240  is considered in resonance. For example, when the optical cavity  220  thickness is L, the resonance wavelength in the optical cavity  220  may be 2 L/q, where q is an integer. The resonance wavelengths (i.e., able to travel through the first mirror  230  and into the optical cavity  220  and reflected from the second mirror  240 ) are the modes that can form standing waves within the optical cavity  220 . The wavelength of the light source  250  of the detection system should match (e.g., be a multiple of) the resonance wavelength of light  252  of the optical cavity  220 , or vice versa, to minimize or prevent intensity loss. 
     The system  200  may further include a detector to monitor one or more characteristics of the optical cavity  220  and thus to detect the presence of an airborne virus target. When present, an airborne virus or viruses may be bound to or captured by the optical grating and thus cause detectable (e.g., quantifiable) changes in the refractive index change and diffraction efficiency of the optical grating. In certain aspects, the detector may be a photodetector or photocell detector  260 . For example, the diffraction of light by the holographic optical element  210  may be detected, for example, by a photocell detector  260  that is sensitive to the wavelength light source  250  and placed at the appropriate angle, for example, off-axis to the holographic optical element  210 , as illustrated. The appropriate angle is the diffraction angle of the grating for the light source  250 . 
     When present, an airborne virus or viruses  222  may be captured by the receptors  218 , such as illustrated in  FIG. 2B , thereby causing detectable changes in the refractive index change and diffraction efficiency change of the holographic optical element  210 , for example, by an increase in the amount of blue radiation falling onto the photocell detector  260 . The photocell detector  260  may detect the changes in the refractive index and/or diffraction efficiency of the holographic optical element  210 . The photocell detector  260  may be in communication with an alarm  270  that is configured to emit a signal for detection by a device or human. In certain aspects, the signal may be sound, light, or other output signal generated when a change in a refractive index and/or diffraction efficiency is recognized by the photocell detector  260 . In certain aspects, the output signal may be fed to a processor/computer and generate an alarm in another system, for example, a display system in a vehicle. For example, as illustrated, the alarm  270  may include a light  272 . As illustrated in  FIG. 2B , when a virus is present the photocell detector  260  detects changes in the refractive index and/or diffraction efficiency of the holographic optical element  210  and the alarm  270  receiving the signal from the photocell detector  260  emits a light so as to alert the user of the presence of the virus. While the systems configured for detecting an airborne virus like SARS-CoV-2 provided by the present technology are particularly suitable for use in passenger compartments of an automobile or other vehicles (e.g., motorcycles, boats, tractors, buses, motorcycles, mobile homes, campers, and tanks) where multiple passengers may be present, they may also be used in a variety of other industries and applications in alternative aspects, such as in buildings, houses, offices, sheds, warehouses, and the like, by way of non-limiting example. 
     In various aspects, the present disclosure provides a method for forming a system configured to detect airborne viruses, such as the SARS-CoV-2. The method may use molecular imprinting technology (“MIT”). For example, the method generally includes forming a thin film coating having an affinity and specificity for the selected virus, for example the SARS-CoV-2; ablating the thin film coating to remove portions of the film and thus define a grating structure; and disposing a plurality of receptors for the selected virus on exposed surfaces of the grating structure. When present, an airborne virus or viruses may be captured by the receptors thereby causing detectable changes in the refractive index and/or diffraction efficiency of the grating structure. 
       FIG. 3  illustrates an example method  300  for forming a system configured to detect airborne viruses, like system  100  illustrated in  FIG. 1A . The method  300  includes preparing  302  a thin film coating  310  on a substrate  320 . For example, as illustrated in  FIG. 4A , the thin film coating  310  may be a self-aligned monolayer (“SAM”) prepared by contacting a surface of the substrate  320  with an organosiloxane precursor. The organosiloxane precursor forms a hydrocarbon-siloxane crosslinked structure having, for example only, 17 or 19 numbered carbon chain, that defines the thin film coating  310 . For example, as illustrated the crosslinking occurs at the silicon-head so as to form a network of —Si—O—Si—O—Si— bonds defining the siloxane. The hydrocarbon moieties or tails are free to float and align with one another so as to minimize the free energy of the system. In this manner, the thin film coating  310  mimics a lipid bilayer of a cell wall. The skilled artisan will appreciate that various other methods may be used to prepare a holographic optical element (“HOE”), including bonding angiotensin converting enzymes directly to a suitable plastic layer of the type used in affinity chromatography for virus isolation. 
     With renewed reference to  FIG. 3 , in certain variations, the method  300  may include ablating  304  the thin film coating  310  to remove portions of the thin film coating  310  and thus define a grating structure  312 . For example, as illustrated in  FIG. 4B , the thin film coating  310  may be ablated using laser holographic techniques, such as ultraviolet laser beam interference  330 , during which pulse duration and energy may be modified so as to form the desired pattern. In certain instances, the thin film coating  310  may be ablated using computer generated holography, which may use spatial light modulator with encoded hologram to form desired pattern on thin film coating  310 . As illustrated, in  FIG. 4C , the grating structure  312  may have a linear pattern that includes a plurality of repeated dimensions (e.g., rows  314 ) that defines an optical grating, for example a holographic optical element (“HOE”). Though not illustrated, the skilled artisan will appreciate that various other patterns may be formed in the thin film coating  310  to form different optical gratings. 
     In certain variations, the method  300  may include contacting  306  the grating structure  312  with a liquid medium that includes a plurality of receptors  316 . Contacting  306  may include any known method of exposing the grating structure  312  to the receptors  216 . For example, contacting  306  may include washing the grating structure  312  with the liquid medium. In certain aspects, the receptors  216  may be dispersed in a suitable liquid medium or solvent that has less affinity for the receptors  216  than the grating structure  312 , so that the grating structure  312  (e.g., distal end) extracts the receptor  216  from the liquid. In still other aspects, the receptors  216  may be dissolved in a suitable solvent that solubilizes the receptors  216 , but has less affinity for the receptor  216  than the grating structure  312 , so that the grating structure  312  extracts the receptor  216  from the liquid. In each instance, the method  300  may further include the liquid from the grating structure  312 , leaving the receptors  216  behind. 
     As illustrated in  FIG. 4A , the receptors  316  may be angiotensin converting enzyme 2 (“ACE2”) having a hydrophobic portion that is embedded into the exposed hydrocarbon tails of the grating structure  312 , including the hydrocarbon-siloxane crosslinked structure, in a manner similar to a cell wall. When present, the airborne virus or viruses  320  may be associated with, bound to, or otherwise captured by the receptors  316  thereby causing detectable changes in optical grating, such as detectable and optionally quantifiable changes in the refractive index and/or diffraction efficiency of the grating structure, such as further detailed above. For example, when present, the airborne virus or viruses  320  may be associated with the receptors  316  via Van Der Waal force attachment. In certain instances, the coronavirus protein prion (i.e., crown) may be captured by the receptor  316 —i.e., the cell wall organelle, the angiotensin converting enzymes. 
     In various aspects, the present disclosure provides a method for forming a system configured to provide an alert as to the presence of an airborne virus or viruses, such as the SARS-CoV-2. Such a system may be part of a vehicle and may be included in a passenger compartment. The method includes preparing a detector, like system  100  illustrated in  FIG. 1A , for example, using method  300  illustrated in  FIG. 3 , and disposing the detector within an optical cavity defined by two opposing reflecting surfaces, such as illustrated in  FIG. 2A . 
     The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.