Sample carrier and air sampler comprising the same

Abstract

A sample carrier (10; 200) for an air sampler for sampling airborne environmental DNA comprises at least one sampling unit (1; 201) and a respective housing (2; 202) for the at least one sampling unit. The at least one sampling unit (1; 201) comprises a respective collecting element (3; 5 203) configured to collect airborne particulate. The at least one sampling unit (1) and / or the respective housing (202) is / are configured to move between a rest position in which the respective collecting element (3; 203) is sealed in the respective housing (2; 202) and a sampling position in which the respective collecting element (3; 203) collects airborne 0 particulate. The sample carrier further comprises first sealing means (4; 204) configured to seal the collecting element (3; 203) in the respective housing (2; 202) when the at least one sampling unit (1) and / or the respective housing (202) is / are in the rest position.

Description

[0001] Sample carrier and air sampler comprising the same

[0002] DESCRIPTION

[0003] The present invention refers to an air sampler and a sample carrier for an air sampler, in particular for sampling airborne environmental DNA.

[0004] Environmental DNA or eDNA is DNA that is collected from a variety of environmental samples such as soil, water, or even air. More particularly, airborne eDNA is comprised of several fractions including, for example, one or more of the following: (1) Bacteria, Viruses, microscopic fungi, microalgae and other microorganism, (2) Propagules such as fungal spores or plant pollen and (3) extra-organismal DNA shed from larger organisms through active or passive shedding. The latter includes, but is not limited to, faeces, mucus, shed skin, and other forms of debris of life or dead organisms or organismal parts generated through abrasion or decomposition and contains genetic material from organisms across the tree of life. The genetic information collected in such samples can be analysed by a variety of molecular methods to detect the presence and estimate the abundance of particular species, generate species lists, describe the diversity of known and unknown organisms, detect and quantify particular genetic sequences of interest (e.g. antibiotic resistance genes), or extract any other information contained in the genetic material. Airborne eDNA can be captured by passive or active sampling with a collecting medium or, in other words, a collecting element. Passive sampling can be obtained by exposing the collecting medium to the air, thereby collecting biological particles through dry or wet deposition on the collecting medium. Active sampling can be obtained by generating an airflow through or toward the collecting element. The collecting medium or collecting element can include, for example, a filter (particularly in the case of active sampling) or a petri dish with or without Agar (particularly in the case of passive sampling), just to mention two examples. DNA carrying particles from all fractions of airborne eDNA (see above) are trapped on the collecting medium and the genetic material can be extracted from this medium using established methods and subsequently analysed using downstream genetic analysis or analysed directly without prior extraction. A filter-based air sampler is disclosed for example by "Harnpicharnchai P, Pumkaeo P, Siriarchawatana P, Likhitrattanapisal S, Mayteeworakoon S, Ingsrisawang L, et al. (2023) AirDNA sampler: An efficient and simple device enabling high-yield, high-quality airborne environment DNA for metagenomic applications. PLoS ONE 18(6): e0287567". This known sampler has a portable ventilation fan and a filter holder that allows multiple sheets of filter to collect air samples simultaneously with the ventilation fan.

[0005] Another example of a filter-based air sampler is disclosed by Lynggaard, C., Bertelsen, M. F., Jensen, C. V., Johnson, M. S., Frpslev, T. G., Olsen, M. T., & Bohmann, K. (2022). Airborne environmental DNA for terrestrial vertebrate community monitoring. Current Biology, 0(0). https: / / doi.Org / 10.1016 / j.cub.2021.12.014

[0006] However, current approaches to airborne eDNA capture face several challenges. First, eDNA samples are extremely susceptible to contamination. Each sample is exposed to the risk of contamination from the human operator, the environment or the sampler itself, during, before and after the intended sampling period as well as to cross-contamination with other samples collected with the same sampler. Another challenge is the storage of the eDNA samples and the preservation of sample integrity before and after sample collection and during transport. Indeed, if no appropriate measures are taken, eDNA samples can degrade rapidly, depending on the abiotic conditions (microbial activity, temperature, humidity, UV exposure) or change substantially until analysis (e.g. through bacterial or fungal or other microorganismal growth or uneven degradation rates). The third challenge in the study of biological aerosols, is that bioaerosol compositions in the air can vary greatly and change rapidly due to both natural and anthropogenic factors and the distribution of specific bioaerosols (e.g. from a specific species) might be stochastic in both space and time. Therefore, it would be desirable to collect multiple samples autonomously, following a programmable sampling scheme. Another problem is that components of micro- and macro-organisms in the air are generally present in lower concentrations than in other environments. These can lead to detection limits and sensitivity problems in subsequent analysis. Thus, many sampling repetitions may have to be done to mitigate the effects of these problems.

[0007] WO 99 / 26464 A2 discloses atmospheric samplers using aerogel filter material. The samplers include one or more cascaded impact sample stations with discs of aerogel as targets. Ambient air carrying particulate matter is introduced into the sampler and the particles are captured by the aerogel in its pore structure. The aerogel filter is next transported to a position where it is fragmented by a spray of water. The fragmented aerogel and the captured particles are transported in the fragmenting water from the sampler for analysis. However, this known solution is unsuitable for sampling eDNA because the captured particles are subject to contamination and quick degradation.

[0008] Therefore, the problem addressed by the present invention is to provide an air sampler and a sample carrier for an air sampler which are structurally and functionally configured to overcome, at least partially, one or more of the disadvantages set out above with reference to the cited prior art.

[0009] It is also an object of the invention to provide an air sampler and a sample carrier for collecting multiple samples of airborne eDNA autonomously following a programmable sampling scheme.

[0010] A further object of the invention is to provide an air sampler and a sample carrier reducing the risk of contamination and / or degradation of airborne eDNA samples.

[0011] Another object of the invention is to provide an air sampler and a sample carrier that allow the samples to be stored at ambient temperature without the need for preservatives.

[0012] It is also an object of the invention to provide a sample carrier and an air sampler which improve the dry collection of eDNA samples.

[0013] An object of the invention is also to provide an air sampler and a sample carrier which improve the known solutions within the scope of a simple, rational and cost-effective solution.

[0014] This problem is solved, and these objects are achieved, at least in part, by the invention, in a first aspect, by means of a sample carrier for an air sampler for sampling airborne environmental DNA, wherein the sample carrier comprises at least one sampling unit, which may comprise a collecting element configured to collect airborne particulate, and a respective housing for the at least one sampling unit.

[0015] Preferably the at least one sampling unit and / or the respective housing is / are configured to move between a rest position in which the collecting element is sealed in the respective housing and a sampling position in which the collecting element collects airborne particulate.

[0016] The sample carrier may also comprise first sealing means configured to seal the collecting element in the respective housing when the at least one sampling unit and / or the respective housing is / are in the rest position.

[0017] It will be appreciated that the sealing of the eDNA sample into a dedicated housing minimizes the risk of cross-contamination with other samples as well as contamination from the environment, from the operator, and from the sampler itself. Furthermore, the sealing of the eDNA sample into a dedicated housing protects the eDNA samples from UV degradation, thereby allowing a longer storage of the same.

[0018] It will be appreciated that, in embodiments of the invention, the sample carrier can switch between the rest position and the sampling position either by moving the at least one sampling unit with respect to the respective housing or by displacing movable parts (in particular, closing means) of the respective housing or both.

[0019] In a second aspect, the invention refers to an air sampler, in particular for sampling airborne environmental DNA, comprising a sample carrier which may have one or more of the features according to the first aspect of the invention.

[0020] The sample carrier preferably comprises at least one sampling unit and a respective housing for each sampling unit.

[0021] The at least one sampling unit (or each sampling unit, where applicable) preferably comprises a respective collecting medium or collecting element configured to collect airborne particulate, such as eDNA. As used herein, the term "airborne particulate" refers preferably to airborne particulate matter.

[0022] Passive sampling can be obtained by exposing the collecting element to the air, thereby collecting biological particles through dry or wet deposition on the collecting element. Active sampling can be obtained by generating an airflow through or toward the collecting element. In particular, active sampling can be obtained either by passing air through the collecting element, or by impinging onto the collecting element. Alternatively, active sampling can also be obtained by cyclonic effect or electrostatic precipitation onto the collecting element. However, a preferred embodiment of the invention provides for active sampling by passing air through the collecting element. Further preferably, the collecting element comprises a filter. The filter may comprise a fiber-based particulate filter (such as a paper filter, a glass fiber filter, a quartz fiber filter, or an HEPA filter), an electret filter, or a membrane filter. Alternatively, or additionally, the collecting element may comprise, for example, an adsorbent material, a petri dish, or a bowl (for wet deposition).

[0023] The at least one sampling unit (or each sampling unit, where applicable) is preferably associated with the respective housing movably between a rest position in which the respective collecting element is stored in the respective housing and a sampling position in which the respective collecting element is located outside of the respective housing so as to collect airborne particulate.

[0024] Preferably the sample carrier comprises first sealing means configured to seal the respective collecting element in the respective housing when the at least one sampling unit is in the rest position.

[0025] The air sampler may further comprise movement means associated with the sample carrier and configured to move the at least one sampling unit from the rest position to the sampling position and vice versa. As used herein, the term "movement means" refers preferably to a movement mechanism.

[0026] It will be appreciated that the enclosure of each eDNA sample into a dedicated housing minimizes the risk of cross-contamination with other samples as well as contamination from the environment, from the operator, and from the sampler itself. Furthermore, the enclosure of each eDNA sample into a dedicated housing protects the eDNA samples from UV degradation, thereby allowing a longer storage of the same.

[0027] As mentioned above with reference to the first aspect, the invention also refers to a sample carrier for an air sampler, in particular for sampling airborne environmental DNA. Preferably, the sample carrier is for use in an air sampler comprising one or more of the features described in connection with the second aspect.

[0028] The sampler carrier preferably comprises a plurality of sampling units. Each sampling unit preferably comprises a collecting element configured to collect airborne particulate, such as eDNA.

[0029] The sample carrier may further comprise a plurality of housings for the sampling units. Each sampling unit is preferably associated with a respective housing from the plurality of housings movably between a rest position in which the collecting element is stored in the respective housing and a sampling position in which the collecting element is located outside of the respective housing so as to collect airborne particulate. As mentioned above, it is understood that in other embodiments the sample carrier may switch between the rest and the sampling position by displacing movable parts (in particular, closing means) of the housing while the respective sampling unit may be stationary.

[0030] The sample carrier may further comprise first sealing means configured to seal each collecting element in the respective housing when the respective sampling unit is in the rest position.

[0031] It will be appreciated that the sample carrier may be used as a replaceable cartridge or cassette for handling and shipping the samples collected by the air sampler. Once all sampling units have been sampled, the used sample carrier can be replaced with a new sample carrier with fresh collecting elements and the used sample carrier can be shipped or transported to a laboratory for analysis. In this manner, the sample carrier may allow the eDNA samples to be easily and safely extracted from the casing of the air sampler and transported from the sampling site to the laboratory. During transportation, the risk of contamination from the environment and the operator, cross-contamination among samples, and degradation of the samples over time are minimized as the samples are safely stored in the respective housings.

[0032] In a third aspect, the invention refers to a kit comprising a sample carrier according to the first aspect of the invention and an engagement member. The engagement element is preferably configured to engage with any one of the sampling units and to move in and out of the respective housing so as to push or pull the respective sampling unit from the rest position to the sampling position and vice versa (in particular, so as to push the respective sampling unit from the rest position to the sampling position and to pull it from the sampling position to the rest position).

[0033] Optionally, the engagement member may be stored in one of the housings of the sample carrier in place of the corresponding sampling unit, in particular when the sampling unit is in the sampling position and / or when the sample carrier is being shipped. In this manner, both the engagement member and the housing in which the engagement member is stored are protected from contamination.

[0034] In a fourth aspect, the invention refers to the use of the air sampler for monitoring biodiversity across one or more taxonomic groups. By way of non-limiting example, the one or more taxonomic groups may be selected from Fungi (in particular micro and macro Fungi), Plants, Arthropods, Vertebrates, Archaea (that is a range of unicellular eucaryotes), and Bacteria. Both terrestrial and aquatic organisms may be detected. For instance, Bacteria from marine / freshwater ecosystems may be detected through sampling of aerosolized surface water.

[0035] In a fifth aspect, the invention refers to the use of the air sampler for detecting a species, such as a single species across the tree of life, or a genetic sequence, such as a gene sequence uniquely identifying a species or a virus or a particular gene with a particular function such as an antibiotic resistance gene or a gene marker for GMO plant or animal.

[0036] The present invention, in at least one of the above aspects, may also have one or more of the following preferred features in addition to those previously mentioned.

[0037] Preferably a desiccating or preservative agent is stored in the at least one sampling unit and / or in the respective housing for drying or preserving the collecting element and / or the collected biological material when the at least one sampling unit and / or the respective housing is / are in the rest position. It will be appreciated that the action of the desiccating or preservative agent is enhanced by the presence of the first sealing means preventing air leaks. In this manner the collected biological material, in particular DNA, is protected and sample alteration due to bacterial growth is prevented.

[0038] Therefore, the first sealing means and the desiccating or preservative agent achieve a combined effect that extends the duration of both the collected sample and the desiccating or preservative agent.

[0039] In embodiments, the desiccating or preservative agent is stored separately from the collecting element. However, it is also contemplated that the preservative agent may comprise a chemical preservative with which the collecting element (in particular, a filter) is treated.

[0040] Preferably the first sealing means are configured to seal both the collecting element and the desiccating or preservative agent maintaining a shared atmosphere between them inside the housing when the at least one sampling unit and / or the respective housing is / are in the rest position. In this manner the first sealing means prevent the contamination and enhance the preservation of the sample.

[0041] Preferably the first sealing means are configured to isolate the desiccating or preservative agent from the external atmosphere when the at least one sampling unit and / or the respective housing is in the sampling position. In this manner the first sealing means prevent the contamination and enhance the preservation of the desiccating or preservative agent.

[0042] In embodiments, the at least one sampling unit is associated with the respective housing movably between a rest position in which the respective collecting element is stored in the respective housing and a sampling position in which the respective collecting element is located outside of the respective housing so as to collect airborne particulate.

[0043] In embodiments, the at least one sampling unit has a first compartment in which the collecting element is stored and a second compartment in which the desiccating or preservative agent is stored. The first and second compartments may be arranged one after the other along a movement direction of the at least one sampling unit between the rest and the sampling position so that in the rest position the first and second compartment are both positioned inside the housing and in the sampling position the first and the second compartment are positioned outside and inside the housing, respectively.

[0044] Preferably the first and the second compartment are connected so as to share the same atmosphere when the at least one sampling unit is in the rest position. In this manner the desiccating or preservative agent in the second compartment can dry or preserve the sample collected in the first compartment.

[0045] Preferably the first sealing means are configured to seal both the first and the second compartment maintaining a shared atmosphere between them inside the housing when the at least one sampling unit is in the rest position. In this manner the first sealing means prevent the contamination and enhance the preservation of the sample.

[0046] Preferably the first sealing means are configured to isolate the second compartment from the external atmosphere when the at least one sampling unit is in the sampling position.

[0047] In embodiments, the respective housing has a first aperture through which the at least one sampling unit is configured to move in and out of the housing. The first sealing means may be secured to the first aperture and / or to the sampling unit so that the sampling unit seals the first aperture when in the rest position.

[0048] In a preferred embodiment, the first sealing means are secured to the housing and configured to slide on the sampling unit as the sampling unit moves between the rest position and the sampling position.

[0049] In embodiments, the sampling unit comprises a separating wall which divides the first compartment from the second compartment. Advantageously the separating wall is spaced apart from the housing so as to leave a gap though which the first and the second compartment share the same atmosphere when the sampling unit is in the rest position. Further advantageously the first sealing means are configured to fill the gap between the separating wall and the housing so as to seal the second compartment inside the housing when the sampling unit is in the sampling position.

[0050] As mentioned previously, the sample carrier may comprise a plurality of sampling units, preferably wherein each sampling unit comprises a respective collecting element configured to collect airborne particulate, and a plurality of housings for the sampling units. Preferably, each sampling unit and / or each housing is configured to move between a respective rest position in which the respective collecting element is sealed in the respective housing and a respective sampling position in which the respective collecting element collects airborne particulate. Preferably, the first sealing means are configured to seal each collecting element in the respective housing when the respective sampling unit and / or the respective housing is / are in the rest position. In this manner, by storing and sealing each sample in a respective housing, the risk of crosscontamination between samples is avoided.

[0051] In embodiments, each sampling unit is associated with a respective housing from the plurality of housings movably between the rest position and the sampling position. Further preferably, the movement means are configured to move any one of the sampling units from the rest position to the sampling position and vice versa. In other words, the movement means may be configured to move the sampling units one by one so as to allow for a flexible sampling order. In embodiments, the movement means are configured to move at least two of the sampling units independently from each other or sequentially, i.e. one after the other, from the rest position to the sampling position and vice versa.

[0052] In this manner, the air sampler allows multiple samples to be taken autonomously, e.g. following a programmable sampling scheme while minimizing the risk of cross-contamination among samples. This also allows it to start sampling when the operator has left for unattended sampling. In addition, the plurality of sampling units allows many sampling repetitions to be performed so as to mitigate the effects of detection limits. Preferably, the sample carrier comprises first sealing means configured to seal each collecting element in the respective housing when the respective sampling unit is in the rest position. In other words, the sampling unit is configured to seal the respective collecting element in the corresponding housing through the first sealing means.

[0053] As used herein, the term "sealing means" refers preferably to a sealing element. As used herein, the term "sealing" refers preferably to air-tight sealing.

[0054] Advantageously, when the sampling unit is stored in the respective housing, the collecting element is enclosed in an air-tight chamber defined by the housing with the respective sampling unit and the first sealing means. In this manner, the risk of contamination, cross-contamination and degradation of the samples stored in the respective housings is further reduced.

[0055] Preferably, a desiccating agent is stored in each housing for drying the collecting element (more particularly, for drying the biological material collected by the collecting element) when the respective sampling unit is in the rest position. Further preferably, when the sampling unit is in the rest position, both the respective collecting element and the respective desiccating agent are enclosed in the air-tight chamber defined by the housing with the respective sampling unit and the first sealing means. It will be appreciated that, by desiccating the collecting element when the respective sampling unit is in the rest position, the desiccating agent improves the sample preservation. Indeed, the absence of sufficient humidity inhibits the enzymatic activity (Deoxyribonuclease enzymes) and bacterial activity, thereby allowing for the preservation of the samples at ambient temperature without the need for cooling / freezing and without the need for preservatives. It is understood, however, that a preservative agent may also be used, without exceeding the scope of the appended claims. Therefore, in embodiments, a preservative agent may be applied to the collecting element (in particular, a filter) for preserving the collected biological material when the respective sampling unit is in the rest position. Preferably, the air sampler comprises an airflow path extending from an air inlet to an air outlet. Advantageously, the collecting element in the sampling position is located across the airflow path so as to collect airborne particulate from an airflow produced through the airflow path. In a preferred embodiment, the air sampler further comprises ventilation means configured to produce the airflow through the airflow path. It will be appreciated that the provision of an airflow path allows for sampling a greater amount of airborne particulate per unit of time. Furthermore, the airflow produced through the airflow path allows for cooling the samples, thereby improving their preservation. In addition, the movement means and the ventilation means can use the same power supply and / or the same control unit, thereby simplifying the structure and reducing the cost of the air sampler. As used herein, the term "ventilation means" refers preferably to a ventilation element. In embodiments, the ventilation means comprise one or more air fans.

[0056] Preferably the airflow path is defined by an air duct which is removable and / or openable for maintenance (e.g., for cleaning or replacement). This allows to minimise the risk of contamination between sampling campaigns. Preferably, each sampling unit is associated with the respective housing through a sliding connection for moving the sampling unit in translation from the rest position to the sampling position and vice versa. It is understood that the sliding connection may be replaced or supplemented by a rotatable connection. In this case, each sampling unit could be associated with the respective housing through the rotatable connection for rotating the sampling unit from the rest position to the sampling position and vice versa.

[0057] Optionally, the air sampler may comprise multiple sample carriers arranged around the airflow path so as to increase the capacity of the air sampler. For example, there may be three or four sample carriers arranged radially around the airflow path and preferably equally spaced from each other. This arrangement allows for a compact design of the air sampler while also increasing the number of samples which can be collected autonomously before replacement of the sample carriers.

[0058] Preferably, the movement means comprise an engagement member. As mentioned previously, the engagement member is configured to engage with any one of the sampling units and to move in and out of the respective housing so as to push the respective sampling unit from the rest position to the sampling position and vice versa. In this manner, when the sampling unit is in the sampling position, the respective housing houses the engagement member which thereby prevents the respective housing from being contaminated.

[0059] In other words, the engagement member is configured to deploy the sampling unit in the sampling position and, at the same time, hermetically close the corresponding housing. In this manner, the inside of the housing is not contaminated and the desiccating agent, if present, is not exposed to outside air, thereby keeping its desiccating ability.

[0060] In embodiments, the movement means comprise a first actuator configured to move the engagement member in and out of the respective housing and / or a second actuator configured to move the engagement member from one housing to another. In this manner, the movement means can engage with any one of the sampling units and move it separately and independently of the other sampling units.

[0061] Preferably, the air sampler comprises second sealing means configured to seal the respective housing when the engagement member is inserted therein. In this manner, when the engagement member is inserted in one of the housings, both the engagement member and the housing in which it is stored are protected from contamination. In embodiments, the second sealing means may be secured to the engagement member so as to seal the respective housing when the engagement member is inserted therein. Alternatively, the first sealing means may also be configured to seal the respective housing when the engagement member is inserted therein. For example, the first sealing means may comprise a first and a second lip seal secured to the housing and configured to slide on the sampling unit and the engagement member, respectively, during the movement of the sampling unit from the rest position to the sampling position and vice versa.

[0062] In embodiments, the housing comprises a first and a second air opening. The housing may also comprise an internal airflow path extending in the region of the collecting element from one of the air openings to the other. The housing may also comprise closing means associated with the air openings movably between the rest position in which the closing means close the air openings so as to seal the at least one sampling unit in the housing, and the sampling position in which the closing means open the air openings so as to allow the collecting element to collect airborne particulate from an airflow through the internal airflow path.

[0063] The first sealing means may be secured to the air openings and / or to the closing means so that the closing means seal the air openings when in the rest position.

[0064] The housing may comprise a primary compartment in which the collecting element is stored and a secondary compartment in which the desiccating or preservative agent is stored. The closing means may be configured to seal the secondary compartment when in the sampling position and to connect the primary and the secondary compartment so that they share they same atmosphere when in the rest position. In this manner the desiccating or preservative agent shares the same atmosphere with the collected sample in the rest position but remains protected inside the housing during sampling.

[0065] Preferably the air openings are defined in the primary compartment. Further preferably the primary compartment is connected to the secondary compartment through an air passage which is positioned adjacent to at least one of the air openings so that the closing means close the air passage when in the sampling position and open the air passage when in the rest position. This arrangement allows for simplifying the structure and reducing the overall dimensions of the sample carrier.

[0066] Preferably auxiliary sealing means are secured to the air passage and / or to the closing means so that the closing means seal the air passage when in the sampling position. This allows for an airtight sealing of the desiccating or preservative agent in the secondary compartment.

[0067] In embodiments, the closing means comprise at least one door hinged to the housing by a hinge positioned between the air passage and at least one of the air openings so that a rotation of the at least one door about the hinge causes the at least one door to close alternatively the air passage, when in the sampling position, or the at least one air opening, when in the rest position.

[0068] Preferably the closing means comprise a first door and a second door hinged to the housing in the region of the first and the second air opening, respectively. This arrangement allows the doors to close the respective air openings when in the rest position.

[0069] In embodiments, the at least one sampling unit divides the primary compartment into a first portion having the first air opening and a second portion having the second air opening so that the internal airflow path between the first and the second air opening passes through the collecting element of the at least one sampling unit. In this manner, the airflow passing through the housing is forced to pass through the collecting element, thereby increasing the collection rate.

[0070] In case of a plurality of sampling units and of respective housings, each housing may comprise respective closing means. The respective closing means may be associated with the air openings of the relevant housing movably between the rest position in which the respective closing means close the air openings of the relevant housing so as to seal the respective sampling unit in the relevant housing, and the sampling position in which the respective closing means open the air openings of the relevant housing so as to allow the collecting element to collect airborne particulate from an airflow through the relevant internal airflow path.

[0071] As mentioned above, the air sampler may comprise movement means. In embodiments, the movement means are configured to move the closing means from the rest position to the sampling position and vice versa.

[0072] The air sampler may comprise a control unit operatively connected to the movement means and configured to control the movement means so that the movement means move the housing (in particular, the closing means) from the rest position to the sampling position and vice versa.

[0073] In case of a plurality of sampling units and of respective housings, the control unit may be configured to control the movement means so that the movement means move at least two of the respective housings (in particular, the respective closing means) independently from each other or sequentially one after the other from the rest position to the sampling position and vice versa.

[0074] Further preferred aspects are also defined in the attached claims as well as by the following description.

[0075] The features and advantages of the invention will be better appreciated from the detailed description of a preferred embodiment thereof, which is illustrated by way of non-limiting example with reference to the appended drawings, in which:

[0076] - Figure 1 is a perspective view of the air sampler of the invention;

[0077] - Figure 2 is a sectional view of the air sampler of Fig. 1;

[0078] - Figure 3 shows the air sampler of the preceding figures in a sampling position, with some parts being removed for clarity;

[0079] - Figure 4 is a perspective view of a sampling unit engaged with an engagement member of the air sampler of the preceding figures;

[0080] - Figure 5 is a perspective view of a housing for the sampling unit of Fig. 4;

[0081] - Figure 6 is an exploded view of a sampling unit of the air sampler according to an embodiment of the invention;

[0082] - Figures 7 and 8 are perspective views of a sample carrier according to an embodiment of the invention in two different positions;

[0083] - Figures 9 and 10 are side sectional views of the sample carrier of Figs. 7 and 8, respectively;

[0084] - Figures 11 and 12 are perspective views of an air sampler comprising a sample carrier according to an embodiment of the invention in two different positions;

[0085] - Figures 13 and 14 are perspective sectional views of the air sampler of Figs. 11 and 12, respectively;

[0086] - Figure 15 is a front view of a sample carrier according to an embodiment of the invention;

[0087] - Figure 16 is a top view of the sample carrier of Fig. 15;

[0088] - Figure 17 is a perspective sectional view of the sample carrier of Fig. 16 according to the section line XVII-XVII;

[0089] - Figures 18 and 19 are side views of the sample carrier of Fig. 17 in two different positions;

[0090] - Figure 20 is a front view of a sample carrier according to an embodiment of the invention;

[0091] - Figure 21 is a top view of the sample carrier of Fig. 20;

[0092] - Figure 22 is a perspective sectional view of the sample carrier of Fig. 21 according to the section line XXII-XXII;

[0093] - Figures 23 and 24 are side views of the sample carrier of Fig. 22 in two different positions.

[0094] In the Figures, the numeral 100 generally indicates an air sampler for sampling airborne particulates, i.e. airborne particulate matter, such as in particular environmental DNA according to the invention.

[0095] The air sampler 100 preferably comprises a casing 101 configured to receive a sample carrier 10. The sample carrier 10 may comprise at least one sampling unit 1 and preferably a plurality of sampling units 1, such as ten to thirty sampling units 1. Preferably, each sampling unit 1 comprises a collecting element 3 configured to collect airborne particulate.

[0096] The sample carrier 10 may further comprise at least one housing 2 for the respective sampling unit 1 and preferably a plurality of housings 2, one for each sampling unit 1. The housings 2 are preferably separated from each other to prevent cross-contamination among the sampling units 1. The casing 101 and / or the housings 2 may be made from a material, such as a plastic material, which is opaque to UV light so as to prevent UV degradation of the samples.

[0097] Advantageously, each sampling unit 1 is associated with a respective housing 2 from the plurality of housings movably in a first direction X between a rest position in which the collecting element 3 is stored in the respective housing 2 as shown in the example of figures 1 and 2, and a sampling position in which the collecting element 3 is located outside of the respective housing 2 so as to collect airborne particulate as shown in the example of figure 3.

[0098] Preferably, each housing 2 develops longitudinally in the first direction X. Further preferably, the housings 2 are stacked on top of each other, such as in a column, in a second direction Y which is preferably perpendicular to the first direction X. In embodiments, the sample carrier 10 may be shaped as a chest of drawers in which the drawers are represented by the sampling units 1 and the seats for the drawers are represented by the housings 2. While it is preferred that the first direction X be horizontal and the second direction Y be vertical, other orientations of the air sampler are also contemplated. For example, it is contemplated that the first direction X be vertical and the second direction Y be horizontal.

[0099] The sample carrier 10 may further comprise first sealing means 4, such as an elastomeric sealing ring or gasket or lip seal, configured to seal each collecting element 3 in the respective housing 2 when the respective sampling unit 1 is in the rest position. As shown in the example of figure 4, the first sealing means 4 may be associated with the sampling units 1 so that each sampling unit 1 is able to move in and out of the respective housing 2 together with the first sealing means 4 with which the sampling unit 1 is associated. Preferably, the first sealing means 4 of each sampling unit 1 are arranged around the respective collecting element 3.

[0100] Preferably, the air sampler 100 comprises movement means 5 associated with the sample carrier 10 and configured to move each sampling unit 1 from the rest position to the sampling position and vice versa. More particularly, the movement means 5 are configured to engage with any one of the sampling units 1 and to move it separately and independently of the other sampling units 1. Preferably, the movement means 5 are further configured to move the sampling units 1 independently from each other or sequentially one after the other from the rest position to the sampling position and vice versa.

[0101] As shown in the example of figure 4, each sampling unit 1 may comprise a frame 19 configured to support the collecting element 3. In the frame 19 there is preferably provided an opening 20 through which the air can reach the collecting element 3. In embodiments, the collecting element 3 may comprise an adsorbent and / or a filter 13. Furthermore, the collecting element 3 may comprise an outer rim which may be arranged around the adsorbent or around the filter 13, as the case may be. Advantageously, the rim is configured to be inserted into the opening 20 and reversibly or removably retained therein, e.g. through a snap-fit connection between the rim and the opening 20. In this manner, the collecting element 3 can be replaced easily with no need to disassemble the frame 19.

[0102] Nevertheless, it is also contemplated that, in embodiments, as shown in the example of figure 6, the frame 19 comprises a first plate 21 and a second plate 22 between which the collecting element 3 is clamped. An Coring 38 may also be clamped between the first and second plates 21, 22. Preferably, the first and second plates 21, 22 are fixed to each other through reversible or removable fasteners. Further preferably, the opening 20 extends through the first and second plates 21, 22 so as to allow the passage of air through the filter 13.

[0103] As shown in the example of figure 5, each housing 2 has preferably at least a first aperture 27 through which the sampling unit 1 can move in and out of the housing. In embodiments, the housing 2 has also a second aperture 28 facing the first aperture 27. Preferably, the housing 2 develops longitudinally in the first direction X between the first aperture 27 and the second aperture 28. When the respective sampling unit 1 is in the rest position, it is preferably located between the first aperture 27 and the second aperture 28. When the respective sampling unit 1 is in the sampling position, it preferably extends outside of the housing 2 through the first aperture 27.

[0104] In embodiments, each housing 2 comprises a base 24 and a cover 25 between which there is defined a seat 26 for receiving the respective sampling unit 1 in the rest position. More particularly, the seat 26 is defined between the base 24, the cover 25, the first aperture 27 and the second aperture 28.

[0105] A desiccating agent 7, such as one or more silica gel beads or a molecular sieve, may be stored in each housing 2 for drying the collecting element 3 of the respective sampling unit 1 when the respective sampling unit 1 is in the rest position. In embodiments, each housing 2 is provided with a recess 29 for storing the desiccating agent 7. The recess 29 may be provided on a surface of the seat 26. The desiccating agent 7 is preferably replaceable, for example through the first or second aperture 27, 28. In embodiments, it is also contemplated that a preservative agent may be used in addition to or as an alternative to the desiccating agent, to preserve the sample when in the rest position.

[0106] With reference to the examples of figures 7 to 14, each sampling unit 1 may have a first compartment la in which the collecting element 3 is stored and a second compartment lb in which a desiccating or preservative agent 7 is stored. Preferably the first and second compartments la, lb are arranged one after the other along the movement direction X of the sampling units between the rest and the sampling position so that in the rest position the first and second compartment la, lb are both positioned inside the respective housing 2 and in the sampling position the first and the second compartment la, lb are positioned outside and inside the respective housing 2, respectively.

[0107] Preferably the first and second compartments la, lb are connected so as to share the same atmosphere when the respective sampling unit 1 is in the rest position.

[0108] Preferably the first sealing means 4 are configured to seal both the first and the second compartment la, lb maintaining a shared atmosphere between them inside the housing 2 when the respective sampling unit 1 is in the rest position.

[0109] Preferably the first sealing means 4 are configured to seal the second compartment lb inside the housing 2 when the respective sampling unit 1 is in the sampling position. In embodiments, this sealing effect may be obtained by the first sealing means 4 either with or without the introduction of the engagement member 15 through the housing 2.

[0110] In embodiments, the respective housing 2 has a first aperture 27 through which the at least one sampling unit 1 is configured to move in and out of the housing 2. In embodiments, the housing 2 has also a second aperture 28 opposite the first aperture 27. Preferably, the movement means 5 are configured to move in and out the housing 2 through the second aperture 28. Preferably, the housing 2 develops longitudinally in the first direction X between the first aperture 27 and the second aperture 28. When the respective sampling unit 1 is in the rest position, it is preferably located between the first aperture 27 and the second aperture 28. When the respective sampling unit 1 is in the sampling position, it preferably extends outside of the housing 2 through the first aperture 27.

[0111] Preferably, the first sealing means 4 comprise a first lip seal 47 secured to the housing 2 in the region of the first aperture 27 so as to abut the respective sampling unit 1 when in the rest position and possibly also in the sampling position.

[0112] Preferably, the first sealing means 4 comprise a second lip seal 48 secured to the housing 2 in the region of the second aperture 28 so as to abut the respective sampling unit 1 when in the rest position.

[0113] When the sampling unit 1 is in the rest position, the first and the second lip seal 47, 48 seal the first and the second aperture 27, 28 of the respective housing 2 so that the collecting element 3 and the desiccating agent 7 are isolated from the external atmosphere.

[0114] The respective sampling unit 1 may comprise a separating wall 23 which divides the first and the second compartment la, lb. The free end of the separating wall 23 may be spaced apart from the ceiling of the respective housing 2 so as to leave a gap 43 through which the first and the second compartment can share the same atmosphere when the sampling unit 1 is in the rest position. The first lip seal 47 may be configured to fill the gap 43 between the separating wall 23 and the housing 2 so as to seal the second compartment lb inside the housing when the sampling unit is in the sampling position.

[0115] As shown in the examples of figures 1 and 2, the air sampler 100 may comprise an airflow path 11 extending from an air inlet 8 to an air outlet 9. In this case, it is preferred that the collecting element 3 comprises a filter 13 or, alternatively, an impactor. It is further preferred that, when the collecting element 3 is in the sampling position, the collecting element 3 is located across the airflow path 11 so as to collect airborne particulate from an airflow produced through the airflow path 11. When the sampling unit 1 is in the sampling position, the sampling unit 1 preferably seals the airflow path 11 so that all the airflow is forced through the collecting element 3. In embodiments, the air sampler 100 comprises ventilation means 12, such as one or more air fans, configured to produce the airflow through the airflow path 11. Alternatively, the airflow through the airflow path 11 may be produced naturally by the wind. A top cover 37 may be provided over the air inlet or outlet 8, 9 to prevent unwanted atmospheric precipitation from entering the airflow path 11. Additionally, or alternatively, the air inlet or outlet 8, 9 may be covered by a mesh to prevent the intrusion of insects, such as spiders, or other unwanted organisms or larger debris. Preferably, the mesh is made from a nonelectrostatic material, such as a non-electrostatic metal, so that the mesh does not retain the airborne particulate to be sampled.

[0116] In embodiments, the air inlet 8 can optionally be fitted with an impactor, such as a single-stage impactor. Advantageously, the impactor acts as a size-selective pre-filter. In this manner, particles above a certain size class can be excluded, e.g. to avoid the collection of pollen.

[0117] Preferably, the airflow path 11 develops longitudinally in the second direction Y. Further preferably, the sample carrier 10 is arranged between the movement means 5 and the airflow path 11 so as to allow the sampling units 1 to interact with the movement means 5 on one side and with the airflow path 11 on the opposite side.

[0118] In embodiments, the air sampler comprises an openable and / or removable air duct defining the airflow path 11. The air duct can be easily opened for cleaning and / or removed for replacement between sampling campaigns to minimise the risk of contamination.

[0119] In embodiments, each sampling unit 1 is associated with the respective housing 2 through a sliding connection 14 for moving the sampling unit 1 in translation in the first direction X from the rest position to the sampling position and vice versa.

[0120] In embodiments, the sliding connection 14 comprises at least one sled 14a configured to slide in a corresponding groove 14b in the first direction X. The sled 14a and the groove 14b may be formed in the sampling unit 1 (in particular in its frame 19) and in the corresponding housing 2, respectively, or vice versa. Both the sled 14a and the corresponding groove 14b are preferably extended longitudinally in the first direction X.

[0121] As shown in the example of figure 2, the airflow path 11 may comprise at least one slot 6 and preferably a plurality of slots 6, one for each housing 2. Each slot 6 is preferably arranged in front of a respective housing 2 in the first direction X. More particularly, each slot 6 faces the first aperture 27 of the corresponding housing 2. Advantageously, each slot 6 is configured to support the respective sampling unit 1 when the respective sampling unit 1 is in the sampling position. Preferably, each slot 6 develops longitudinally in the first direction X, in particular in continuation with the groove(s) 14b of the corresponding housing 2. Further preferably, the slots 6 are stacked on top of each other along the longitudinal development of the airflow path 11 in the second direction Y.

[0122] Alternatively, as shown in the example of figures 11-14, the air duct may be fully open toward the sample carrier and sealed by the latter, possibly using further sealing means arranged around the sample carrier. When the sampling units are in the sampling position, their stability may be ensured by the sliding connection 14. The slots 6 may also be absent in this embodiment.

[0123] In embodiments, the movement means 5 comprise an engagement member 15 which is configured to engage with any one of the sampling units 1 and to move in and out of the respective housing 2 so as to push the respective sampling unit 1 from the rest position to the sampling position and vice versa. As shown in the example of figure 4, the engagement member 15 may extend longitudinally in the first direction X from a first end 31 to a second end 32. The first end 31 comprises first connection means 33, such as dovetail connection means or magnetic connection means, configured to reversibly or removably connect the first end 31 to any one of the sampling units 1. More particularly, the first connection means 33 are configured to constrain the engagement member 15 to the sampling unit 1 in the first direction X while possibly leaving a degree of freedom between the engagement member 15 and the sampling unit 1 in the second direction Y. In this manner, the engagement member 15 is configured to disengage from a sampling unit 1 and engage with another sampling unit 1 through the first connection means 33 by moving in translation in the second direction Y. As used herein, the term "connection means" refers preferably to a connector. In embodiments, the engagement member 15 may be made as a solid piece or, alternatively, it may comprise two plates connected with two rods.

[0124] Preferably, there are provided second sealing means 18 configured to seal the respective housing 2 when the engagement member 15 is inserted therein. As shown in the example of figure 4, the second sealing means 18 may be associated with the engagement member 15. In particular, the second sealing means 18 may comprise first and second elastomeric sealing rings or gaskets 181, 182 arranged around the first and second ends 31, 32 of the engagement member so as to prevent the air from entering the housing 2 when the engagement member 15 is inserted therein.

[0125] As shown in the example of figures 1 and 2, the movement means 5 preferably comprise a first actuator 16 configured to move the engagement member 15 in and out of the respective housing 2 in the first direction X. The second end 32 of the engagement member is preferably connected to the first actuator 16. In embodiments, the second end 32 comprises second connection means 34 configured to reversibly or removably connect the second end 32 to the first actuator 16. In the example of figure 4, the second connection means 34 comprise holes and screws but it is understood that other reversible or removable fasteners are also contemplated. The first actuator 16 may comprise a first electric motor 161 connected to a first endless screw 162 which develops longitudinally in the first direction X. The first actuator 16 may further comprise a first screw nut 163 which is connected to the second end 32 of the engagement member. Advantageously, the first screw nut 163 is configured to convert a rotation of the first endless screw 162 into a translation of the engagement member 15 in the first direction.

[0126] The movement means 5 preferably comprise a second actuator 17 configured to move the engagement member 15 from one housing 2 to another housing 2 in the second direction Y. The second actuator 17 is preferably mounted on the casing 101 and connected to the first actuator 16 so as to be able to move the first actuator 16 together with the engagement member 15 in the second direction Y. The second actuator 17 may comprise a second electric motor 171 which is mounted on the casing 101. The second electric motor 171 is preferably connected to a second endless screw 172 which develops longitudinally in the second direction Y. The second actuator 17 may further comprise a second screw nut 173 which is connected to the first actuator 16 and in particular to the first electric motor 161. Advantageously, the second screw nut 173 is configured to convert a rotation of the second endless screw 172 into a translation of the first actuator 16 together with the engagement member 15 in the second direction Y.

[0127] In the embodiment disclosed above, the engagement member 15 is preferably configured to move in the second direction Y from one sampling unit to the other. However, it is also contemplated that the sample carrier may be configured to move in the second direction Y, in addition or alternative to the movement of the engagement member 15 in the same direction.

[0128] In embodiments, the air sampler 100 comprises a control unit operatively connected to the movement means 5 and configured to control the movement means 5 so that the movement means 5 move the sampling units 1. More particularly, the control unit is configured to control the movement means 5 so that the movement means 5 move at least two of the sampling units 1 independently from each other or sequentially one after the other from the rest position to the sampling position and vice versa.

[0129] The control unit may also be operatively connected to the ventilation means 12 so as to coordinate the operation of the movement means 5 with the operation of the ventilation means 12. In embodiments, the air sampler further comprises a power supply, such as a battery and / or a solar panel, configured to supply power to the movement means 5 and / or the ventilation means 12. Preferably, the sample carrier 10 is replaceable. In embodiments, the sample carrier 10 is configured to be plugged in and out of the casing 101 of the air sampler. As shown in the examples of figures 1 and 2, the casing 101 may have a chamber 30 configured to receive the sample carrier 10. Preferably, the chamber 30 is arranged between the movement means 5 and the airflow path 11 so as to allow the sample carrier 10 to interact with the movement means 5 on one side and with the airflow path 11 on the opposite side. Further preferably, the chamber 30 develops longitudinally in the second direction Y so as to be able to receive the sample carrier 10 in the second direction Y.

[0130] A passage 35 may be provided through the casing 101 for moving the sample carrier in and out of the chamber 30. Preferably, the chamber 31 is configured to receive the sample carrier 10 through the passage 35 in the second direction Y. Alternatively, the passage 35 for inserting the sample carrier 10 may be positioned in a side wall of the casing 101 so that the sample carrier may be inserted through the passage 35 in a direction which is perpendicular to the second direction Y.

[0131] In embodiments, there are provided reversible or releasable locking means, such as a reversible or releasable locking element, configured to reversibly or releasable lock the sample carrier 10 in the chamber 31. The reversible or releasable locking means may comprise a removable lid 36 configured to close the passage 35. When the passage 35 is closed, the removable lid 36 advantageously prevents the sample carrier 10 from moving out of the chamber 30 in the second direction Y. Alternatively, the reversible or releasable locking means may be formed in the sample carrier itself and / or in the casing 101.

[0132] In embodiments, the air sampler 100 comprises one or more sensors for monitoring the sampling conditions. In embodiments, the sensors may include environmental sensors. For instance, the sensors may include an airflow sensor, a temperature sensor, a humidity sensor and / or a weather station. The weather station may include a wind direction sensor, a wind speed sensor, a barometric pressure sensor, an irradiation sensor and / or a precipitation sensor. The sensors may be operatively connected to the control unit of the air sampler so as to control the movement means 5 and / or the ventilation means 12 as a function of the sampling conditions detected by the sensors. Advantageously the sensors allow for implementing an intelligent sampling strategy which may be preprogrammed or decided by a locally run Al model.

[0133] In embodiments, the air sampler 100 comprises a communication module by which the air sampler can be remotely monitored and / or controlled. In particular, the communication module may be configured to remotely transmit the data provided by the sensors. The data provided by the sensors may concern a sampling status or progress or potential errors, also allowing a remote intervention. In addition, the communication module may be configured to receive instructions for piloting the movement means 5 and / or the ventilation means 12 from a remote location.

[0134] According to the invention, the sample carrier for an air sampler for sampling airborne eDNA may also take the form of the exemplary embodiments shown in figures 15-19 or 20-24, respectively, where the sample carrier has been generally designated with the numeral 200. The sample carrier 200 comprises at least one sampling unit 201 which may comprise a collecting element 203 configured to collect airborne particulate.

[0135] The sample carrier 200 further comprises a respective housing 202 for the at least one sampling unit. The respective housing 202 may be configured to move between a rest position in which the collecting element 203 is sealed in the respective housing and a sampling position in which the collecting element collects airborne particulate.

[0136] The sample carrier 200 may further comprise first sealing means 204 configured to seal the collecting element 203 in the respective housing 202 when the respective housing 202 is in the rest position.

[0137] A desiccating or preservative agent 207 may be stored in the respective housing 202 for drying or preserving the collected biological material when the at least one sampling unit 201 is in the rest position.

[0138] The sample carrier 200 may comprise a plurality of sampling units 201, each sampling unit 201 comprising a respective collecting element 203 configured to collect airborne particulate, and a plurality of housings 202 for the sampling units.

[0139] The housings 202 may be stacked on top of each other. Preferably the housings 202 are separate and independent from one other.

[0140] Each housing 202 may be configured to move between a respective rest position in which the respective collecting element 203 is sealed in the respective housing and a respective sampling position in which the respective collecting element collects airborne particulate.

[0141] The first sealing means 204 may be configured to seal each collecting element 203 in the respective housing 202 when the respective housing 202 is in the rest position.

[0142] The housing 202 may comprise a first and a second air opening 208, 209. The housing 202 may also comprise an internal airflow path 211 extending in the region of the collecting element 203 from one of the air openings 208, 209 to the other. The housing may also comprise closing means 210 associated with the air openings 208, 209 movably between the rest position in which the closing means close the air openings 208, 209 so as to seal the at least one sampling unit 201 in the housing 202, and the sampling position in which the closing means open the air openings so as to allow the collecting element 203 to collect airborne particulate from an airflow through the internal airflow path 211.

[0143] Advantageously, when the housing 202 is in the sampling position, the internal airflow path 211 may form a segment of the airflow 11. For example, there may be two air ducts on either side of the housing 202, each air duct being open only on one side such that the ventilation generates a pressure differential forcing the air through the housing.

[0144] In case of a plurality of sampling units 201 and of a plurality of respective housings 202, each housing may comprise respective closing means 210. The respective closing means 210 may be associated with the air openings 208, 209 of the relevant housing 202 movably between the rest position in which the respective closing means close the air openings 208, 209 of the relevant housing so as to seal the respective sampling unit 201 in the relevant housing 202, and the sampling position in which the respective closing means open the air openings of the relevant housing so as to allow the collecting element 203 to collect airborne particulate from an airflow through the relevant internal airflow path 211.

[0145] The first sealing means 204 may be secured to the air openings 208, 209 and / or to the closing means 210 so that the closing means 210 seal the air openings 208, 209 when in the rest position.

[0146] The housing 202 may comprise a primary compartment 202a in which the collecting element 203 is stored and a secondary compartment 202b in which the desiccating or preservative agent 207 is stored. The closing means 210 may be configured to seal the secondary compartment 202b when in the sampling position and connect the primary and the secondary compartment 202a, 202b when in the rest position.

[0147] The air openings 208, 209 are preferably defined in the primary compartment 202a. The primary compartment may be connected to the secondary compartment 202b through a air passage 206 which is positioned adjacent to at least one of the air openings 208, 209 so that the closing means 210 close the air passage 206 when in the sampling position and open the air passage 206 when in the rest position.

[0148] Auxiliary sealing means 230 may be secured to the air passage 206 and / or to the closing means 210 so that the closing means 210 seal the air passage 206 when in the sampling position.

[0149] In embodiments, the closing means 210 comprise at least one door 289 hinged to the housing 202 by a hinge 214 positioned between the air passage 206 and at least one of the air openings 209 so that a rotation of the at least one door 289 about the hinge 214 causes the at least one door 289 to close alternatively the air passage 206, when in the sampling position, or the at least one air opening 209, when in the rest position.

[0150] Preferably the closing means 210 comprise a first door 288 and a second door 289 hinged to the housing 202 in the region of the first and the second air opening 208, 209, respectively. The first and the second door 288, 289 may be configured to pivot from the rest position to the sampling position and vice versa by action of the movement means 5 such as a motor.

[0151] With reference to the embodiment of figures 7-10, the at least one sampling unit 201 may divide the primary compartment into a first portion 218 having the first air opening 208 and a second portion 219 having the second air opening 209 so that the internal airflow path 211 between the first and the second air opening 208, 209 passes through the collecting element 203 of the at least one sampling unit.

Claims

CLAIMS1. Sample carrier (10; 200) for an air sampler for sampling airborne environmental DNA, the sample carrier (10; 200) comprising:- at least one sampling unit (1; 201) comprising a collecting element (3; 203) configured to collect airborne particulate;- a respective housing (2; 202) for the at least one sampling unit, the at least one sampling unit (1) and / or the respective housing (202) being configured to move between a rest position in which the collecting element (3; 203) is sealed in the respective housing and a sampling position in which the collecting element collects airborne particulate; and- first sealing means (4; 204) configured to seal the collecting element (3; 203) in the respective housing (2; 202) when the at least one sampling unit (1) and / or the respective housing (202) is / are in the rest position.

2. Sample carrier (10; 200) according to claim 1, wherein a desiccating or preservative agent (7; 207) is stored in the at least one sampling unit (1) and / or in the respective housing (2; 202) for drying or preserving the collecting element (3; 203) and / or the collected biological material when the at least one sampling unit (1) and / or the respective housing (202) is / are in the rest position.

3. Sample carrier (10; 200) according to claim 2, wherein the first sealing means (4; 204) are configured to seal both the collecting element (3; 203) and the desiccating or preservative agent (7; 207) maintaining a shared atmosphere between them inside the housing (2; 202) when theat least one sampling unit (1) and / or the respective housing (202) is / are in the rest position.

4. Sample carrier (10; 200) according to claim 2 or 3, wherein the first sealing means (4; 204) are configured to isolate the desiccating or preservative agent (7; 207) from the external atmosphere when the at least one sampling unit (1) and / or the respective housing (201) is / are in the sampling position.

5. Sample carrier (10) according to any one of the preceding claims, wherein the at least one sampling unit (1) is associated with the respective housing (2) movably between a rest position in which the respective collecting element (3) is stored in the respective housing (2) and a sampling position in which the respective collecting element (3) is located outside of the respective housing (2) so as to collect airborne particulate.

6. Sample carrier (10) according to claim 5 when dependent on any one of claims 2 to 4, wherein the at least one sampling unit (1) has a first compartment (la) in which the collecting element (3) is stored and a second compartment (lb) in which the desiccating or preservative agent (7) is stored, the first and second compartments (la, lb) being arranged one after the other along a movement direction (X) of the at least one sampling unit between the rest and the sampling position so that in the rest position the first and second compartment (la, lb) are both positioned inside the housing (2) and in the sampling position the first and the second compartment (la, lb) are positioned outside and inside the housing (2), respectively.

7. Sample carrier (10) according to claim 6, wherein the first and the second compartment (la, lb) are connected so as to share the same atmosphere when the at least one sampling unit (1) is in the rest position.

8. Sample carrier (10) according to any one of claims 5 to 7, wherein the respective housing (2) has a first aperture (27) through which the at least one sampling unit (1) is configured to move in and out of the housing (2), the first sealing means (4) being secured to the first aperture (27) and / or to the sampling unit (1) so that the sampling unit (1) seals the first aperture (27) when in the rest position.

9. Sample carrier (10) according to claim 8 when dependent on claim 6 or 7, wherein the sampling unit (1) comprises a separating wall (23) which divides the first compartment (la) from the second compartment (lb), the separating wall (23) being spaced apart from the housing (2) so as to leave a gap (43) through which the first and the second compartment share the same atmosphere when the sampling unit (1) is in the rest position, the first sealing means (4) being configured to fill the gap (43) between the separating wall (23) and the housing (2) so as to seal the second compartment (lb) inside the housing when the sampling unit is in the sampling position.

10. Sample carrier (200) according to claim any one of claims 1 to 4, wherein the housing (202) comprises a first and a second air opening (208, 209), an internal airflow path (211) extending in the region of the collecting element (203) from one of the air openings (208, 209) to the other, and closing means (210) associated with the air openings (208,209) movably between the rest position in which the closing means close the air openings (208, 209) so as to seal the at least one sampling unit (201) in the housing (202), and the sampling position in which the closing means open the air openings so as to allow the collecting element (203) to collect airborne particulate from an airflow through the internal airflow path (211).

11. Sample carrier (200) according to claim 10, wherein the first sealing means (204) are secured to the air openings (208, 209) and / or to the closing means (210) so that the closing means (210) seal the air openings (208, 209) when in the rest position.

12. Sample carrier (200) according to claim 10 or 11, wherein the housing (202) comprises a primary compartment (202a) in which the collecting element (203) is stored and a secondary compartment (202b) in which the desiccating or preservative agent (207) is stored, the closing means (210) being configured to seal the secondary compartment (202b) when in the sampling position and to connect the primary and the secondary compartment (202a, 202b) so that they share the same atmosphere when in the rest position.

13. Sample carrier (200) according to claim 12, wherein the air openings (208, 209) are defined in the primary compartment (202a), the primary compartment being connected to the secondary compartment (202b) through an air passage (206) which is positioned adjacent to at least one of the air openings (208, 209) so that the closing means (210) close the air passage (206) when in the sampling position and open the air passage (206) when in the rest position.

14. Sample carrier (200) according to claim 13, wherein auxiliary sealing means (230) are secured to the air passage (206) and / or to the closing means (210) so that the closing means (210) seal the air passage (206) when in the sampling position.

15. Sample carrier (200) according to claim 13 or 14, wherein the closing means (210) comprise at least one door (289) hinged to the housing (202) by a hinge (214) positioned between the air passage (206) and at least one of the air openings (209) so that a rotation of the at least one door (289) about the hinge (214) causes the at least one door (289) to close alternatively the air passage (206), when in the sampling position, or the at least one air opening (209), when in the rest position.

16. Sample carrier (200) according to any one of claims 10 to 15, wherein the closing means (210) comprise a first door (288) and a second door (289) hinged to the housing (202) in the region of the first and the second air opening (208, 209), respectively.

17. Sample carrier (200) according to any one of claims 12 to 16, wherein the at least one sampling unit (201) divides the primary compartment (202a) into a first portion (218) having the first air opening (208) and a second portion (219) having the second air opening (209) so that the internal airflow path (211) between the first and the second air opening (208, 209) passes through the collecting element (203) of the at least one sampling unit.

18. Sample carrier (10; 200) according to any one of the preceding claims, comprising:- a plurality of sampling units (1; 201), each sampling unitcomprising a respective collecting element (3; 203) configured to collect airborne particulate; and- a plurality of housings (2; 202) for the sampling units, each sampling unit (1) and / or each housing (202) being configured to move between a respective rest position in which the respective collecting element (3; 203) is sealed in the respective housing and a respective sampling position in which the respective collecting element collects airborne particulate; wherein the first sealing means (4; 204) are configured to seal each collecting element (3; 203) in the respective housing (2; 202) when the respective sampling unit (1) and / or the respective housing (202) is / are in the rest position.

19. Sample carrier (10) according to claim 18, wherein each sampling unit (1) is associated with the respective housing (2) from the plurality of housings movably between the rest position in which the collecting element (3) is stored in the respective housing (2) and the sampling position in which the collecting element (3) is located outside of the respective housing (2) so as to collect airborne particulate.

20. Sample carrier (200) according to claim 18 when dependent on any one of claims 10 to 17, wherein each housing (202) comprises respective closing means (210), the respective closing means (210) being associated with the air openings (208, 209) of the relevant housing movably between the rest position in which the respective closing means close the air openings (208, 209) of the relevant housing so as to seal the respective sampling unit (201) in the relevant housing (202),and the sampling position in which the respective closing means open the air openings of the relevant housing so as to allow the collecting element (203) to collect airborne particulate from an airflow through the relevant internal airflow path (211).

21. Air sampler (100) for sampling airborne environmental DNA, comprising- the sample carrier (10; 200) according to any one of the preceding claims; and- movement means (5) associated with the sample carrier (10; 200) and configured to move the at least one sampling unit (1) and / or the respective housing (202) from the rest position to the sampling position and vice versa.

22. Air sampler (100) according to claim 21 when dependent on any one of claims 18 to 20, wherein the movement means (5) are configured to move any one of the sampling units (1) and / or of the respective housings (202) from the rest position to the sampling position and vice versa.

23. Air sampler (100) according to claim 21 or 22, comprising an airflow path (11) extending from an air inlet (8) to an air outlet (9) and ventilation means (12) configured to produce an airflow through the airflow path (11), wherein the collecting element (3; 203) in the sampling position is located across the airflow path (11) so as to collect airborne particulate from the airflow produced by the ventilation means (12).

24. Air sampler (100) according to claim 23, wherein the airflow path (11) is defined by an air duct which is openable and / or removable formaintenance.

25. Air sampler (100) according to any one of claims 21 to 24, wherein the at least one sampling unit (1) is associated with the respective housing (2) through a sliding connection (14) for moving the sampling unit (1) in translation from the rest position to the sampling position and vice versa.

26. Air sampler (100) according to any one of the preceding claims when dependent on claim 22, wherein the movement means (5) comprise an engagement member (15) which is configured to engage with any one of the sampling units (1) and to move in and out of the respective housing (2) so as to push or pull the respective sampling unit (1) from the rest position to the sampling position and vice versa.

27. Air sampler (100) according to claim 26, wherein the movement means (5) comprise a first actuator (16) configured to move the engagement member (15) in and out of the respective housing (2) and / or a second actuator (17) configured to move the engagement member (15) from one housing (2) to another.

28. Air sampler (100) according to claim 26 or 27, wherein the first sealing means (4) are configured to seal the respective housing (2) when the engagement member (15) is inserted therein or wherein second sealing means (18) are associated with the engagement member (15) and configured to seal the respective housing (2) when the engagement member (15) is inserted therein.

29. Air sampler (100) according to any one of claims 21 to 24 when dependent on any one of claims 10 to 17, wherein the movement means(5) are configured to move the closing means (210) from the rest position to the sampling position and vice versa.

30. Air sampler (100) according to any one of claims 21 to 29, comprising a control unit operatively connected to the movement means (5) and configured to control the movement means (5) so that the movement means (5) move the at least one sampling unit (1) and / or the respective housing (202) from the rest position to the sampling position and vice versa.

31. Air sampler (100) according to claim 30, wherein the control unit is configured to control the movement means (5) so that the movement means (5) move at least two of the sampling units (1) and / or of the respective housings (202) independently from each other or sequentially one after the other from the rest position to the sampling position and vice versa.

32. Air sampler (100) according to claim 30 or 31 when dependent on at least claim 23, wherein the control unit is operatively connected to the ventilation means (12) so as to coordinate the operation of the movement means (5) with the operation of the ventilation means (12).

33. Air sampler (100) according to any one of claims 21 to 32, comprising one or more sensors for monitoring sampling conditions.

34. Air sampler (100) according to claim 33 when dependent on at least claim 30, wherein the one or more sensors is / are operatively connected to the control unit so as to control the movement means (5) as a function of the sampling conditions detected by the one or more sensors.

35. Air sampler (100) according to claim 33 or 34, comprising a communication module configured to remotely transmit the data provided by the one or more sensors so as to allow for monitoring and / or controlling the air sampler from remote.

36. Air sampler (100) according to any one of claims 21 to 35, comprising a casing (101) configured to receive the sample carrier (10; 210), the sample carrier (10; 210) being replaceable by plugging it in and out of the casing (101).

37. Use of the air sampler according to any one of claims 21 to 36 for monitoring biodiversity across one or more taxonomic groups.

38. Use of the air sampler according to any one of claims 21 to 36 for detecting a species or a gene sequence.

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