Microcapsules for controlled release in enclosed environments

Abstract

The invention relates to chitosan-based microcapsules for detecting, treating, or preventing fungal growth in enclosed environments. These microcapsules release at least one compound when triggered during fungal development. This selective release mechanism ensures efficient use of the compounds and minimizes waste. The invention also relates to a fungal growth detection kit for enclosed environments, the kit comprising the microcapsules and a detector configured to detect the compounds and emit a signal indicating the presence of fungal growth. Abstract figure: Figure 1

Description

Title of the invention: Microcapsules for controlled release in closed environments technical field

[0001] This disclosure relates to microcapsules for detecting, treating or preventing fungal growth in closed environments. Previous technique

[0002] Fungi, such as molds, present in enclosed indoor environments can cause allergies, infections, and irritations through the inhalation of spores or damage objects that may be present. The management of fungal growth on the surface of construction or decorative products or inside storage products (e.g., wooden boxes, cardboard, paper, etc.) has traditionally relied on chemical antifungal agents, used both preventively and curatively. However, the use of such treatments raises concerns about their long-term effects on health and the environment. The European Union's REACH regulation encourages the adoption of alternative methods that are safer, more sustainable, and more environmentally friendly.

[0003] Detecting fungi, such as molds, presents a major challenge due to their often invisible and hidden nature. Fungi can grow in inaccessible places, making early detection particularly difficult. Consequently, such treatments are often applied indiscriminately. This means that fungicide products are deployed in various areas likely to be affected by fungi, without knowing their exact location. While indiscriminate application may prevent some infestations, it also entails a considerable risk of waste. The products used may never reach the affected areas and remain inactive, resulting in unnecessary additional costs and inefficient deployment of fungicide products.Furthermore, the widespread application of these treatments can lead to negative health and environmental impacts, adding an additional layer of complexity to fungal management.

[0004] It is therefore necessary to develop alternative treatments aimed at detecting, treating, or preventing fungal growth in enclosed environments, thereby reducing the exposure of people and objects to harmful fungi and limiting the rehabilitation costs caused by such infestations. It is also necessary that these treatments minimize the waste of antifungal products while ensuring effective control of fungi, but also more sustainable and more environmentally friendly. Summary

[0005] This disclosure improves the situation.

[0006] According to a first aspect, the present invention relates to chitosan-based microcapsules for detecting, treating or preventing fungal growth in a closed environment by releasing at least one compound contained in the microcapsules, the release being triggered during fungal growth.

[0007] The chitosan-based microcapsules according to the invention provide a targeted response to secreted substances or stimuli generated during fungal growth in the atmosphere of an enclosed environment. By being designed to release their specific compounds in response to these substances or stimuli, the microcapsules enable the effective detection, treatment, or prevention of fungal growth without unnecessary dispersion of antifungal agents, optimizing the frequency and quantity of treatments required over time, as well as their use, and minimizing potential waste. Conversely, in the absence of fungal growth, the microcapsules do not open and do not release their compounds.

[0008] Furthermore, the compounds thus encapsulated are protected from volatilization or premature degradation. This encapsulation prolongs the shelf life of the compounds until they are released.

[0009] According to a second aspect, the invention proposes a method for detecting, treating, or preventing fungal growth in an enclosed environment, the method comprising:

[0010] a) the supply of microcapsules according to the first aspect,

[0011] b) the triggering of the opening of microcapsules during fungal development,

[0012] c) the release of at least one compound contained in the microcapsules

[0013] d) optionally, the detection of the presence of fungi, and / or

[0014] e) the inhibition of fungal development.

[0015] According to one embodiment, the microcapsules are present in a concentration between 1 and 1000 microcapsules per cm2, preferably between 1 and 100 microcapsules per cm2, preferably between 1 and 50 microcapsules per cm2.

[0016] The defined concentration range of microcapsules per surface area ensures optimal distribution of the active agents over the entire treated surface. Below this range, the detection or prevention rate of fungal growth may not be sufficient. satisfactory, whereas too high a concentration would lead to an overabundance of microcapsules, and therefore unnecessary use of them.

[0017] According to a third aspect, the invention proposes a kit for detecting fungal development in a closed environment comprising microcapsules according to the first aspect and a detector configured to detect the presence of a compound released by the microcapsules and to emit a signal notifying the presence of fungi.

[0018] The detection kit offers an all-in-one solution for monitoring fungi, enabling more efficient management of antifungal treatments. The detector's ability to emit a signal upon detecting compounds, such as volatile organic compounds or tracers like dyes and / or fluorescent markers, released from inside the microcapsules serves as an alert mechanism, facilitating rapid awareness of the presence of fungi. By precisely identifying contaminated areas, it becomes possible to apply additional antifungal treatments in a targeted manner, thus avoiding waste.

[0019] According to a fourth aspect, the invention relates to a method for detecting fungal growth in an enclosed environment comprising:

[0020] a) the provision of a detection kit according to the third aspect,

[0021] b) the triggering of the opening of microcapsules during the fungal development of fungi,

[0022] c) the release of at least one compound contained in the microcapsules,

[0023] d) the detection by the detector of the presence of a compound released by the microcapsules,

[0024] e) the emission of a signal by the detector to notify the presence of fungal growth, and

[0025] f) possibly, the inhibition of fungal growth.

[0026] According to a fifth aspect, the invention relates to a method for manufacturing microcapsules according to one of the preceding aspects.

[0027] The optional step of inhibiting fungal growth, following detection, offers a proactive approach not only to identify but also to control fungal growth. This integrated detection and inhibition strategy helps maintain environmental hygiene and reduce health risks or the risk of damage to or weakening of objects in an enclosed environment.

[0028] “Inhibition of fungal growth” means any action aimed at slowing down, stopping, or preventing the growth and spread of fungi. This action includes a fungistatic effect preventing the growth and multiplication of fungi without necessarily destroying them and / or a fungicidal effect leading to the destruction of fungi. Brief description of the drawings

[0029] Other features, details and advantages will become apparent from reading the detailed description below and from analyzing the accompanying drawings, in which: Fig. 1

[0030] [Fig. 1] shows a photograph of an experimental setup for determining the antifungal power of microcapsules, the setup comprising an emission chamber inside which three pieces of contaminated glass fiber are arranged in a U-shape. Fig. 2

[0031] [Fig.2] shows a table of the results of analyses and visual observations relating to the antifungal power of microcapsules containing cinnamon essential oil. Detailed description

[0032] According to one aspect of the present invention, chitosan-based microcapsules make it possible to detect, treat or prevent fungal growth in a closed environment by releasing at least one compound contained in the microcapsules, the release being triggered during fungal growth.

[0033] The inventors propose microcapsules with a chitosan-based shell. This particular choice of shell material enables the microcapsules to open when exposed to an atmosphere containing at least one substance secreted during fungal growth or any other stimulus generated during such growth. This choice is also justified by its biocompatibility, biodegradability, non-toxicity, bacteriostatic, antifungal, and flame-retardant properties. The use of chitosan would therefore slow the spread of potential fires while being biocompatible, thus reducing the environmental impact associated with the use of synthetic materials.

[0034] The detection and response capability of microcapsules improves the maintenance of closed environments by minimizing the need for frequent manual interventions for fungal control.

[0035] Without wishing to be bound by any theory, the inventors believe that exo-BD-glucosaminidase—a hydrolase that can be secreted by fungi—acts on the [3(1-4)] bond of chitosan at its non-reducing end. Thus, the chitosan-based shells of the microcapsules would gradually degrade upon contact with the specific environment in which the fungi grow, thereby triggering the opening of the microcapsule and allow a gradual release of volatile organic compounds.

[0036] Chitosan may have a degree of deacetylation between 0% and 50%, preferably less than 30%. A degree less than 20% may enhance the polycationic character of the chitosan chains.

[0037] By “microcapsule” is meant a hollow spherical or spheroidal structure of micrometric size called a wall or shell or envelope in which a substance is enclosed.

[0038] The terms "shell," "envelope," or "wall" refer to an external structure that surrounds and protects the contents of a microcapsule. These terms may be used interchangeably. The primary function of the shell is to provide a physical barrier between the interior of the microcapsule and its external environment, thereby preventing the diffusion or premature release of the encapsulated contents. The shell may be formed of a single layer or of at least two superimposed layers.

[0039] Microcapsules can be mononucleated (or monocore) or polynucleated (or polycore). "Mononucleated or monocore" refers to a microcapsule whose entire encapsulated content is contained within the shell without compartmentalization. "Polynucleated or polycore" refers to an aggregation of monocore microcapsules.

[0040] The microcapsules may have a single shell or at least two shells arranged concentrically, allowing a progressive release of VOCs.

[0041] According to the embodiment, the microcapsules can be multilayered.

[0042] The shell thickness can vary between 1 nm and 40 pm, preferably between 50 nm and 20 pm.

[0043] By "enclosed environment," we mean an environment surrounded or closed off by physical barriers, such as walls, ceilings, or other enclosures, in order to limit or control the exchange of matter and energy with the external environment. This configuration allows for the regulation of environmental conditions such as temperature, humidity, and air quality. Enclosed environments can vary in scale and complexity. Smaller-scale examples include archive boxes, which are designed to protect documents and photographs from environmental damage by controlling exposure to light, humidity, and air. Larger-scale examples are living or storage rooms.

[0044] The terms “enclosed environment”, “enclosed space” or “enclosed environment” can be used interchangeably.

[0045] By "release" is meant the release of at least one compound contained in the microcapsules from the inside to the surrounding environment.

[0046] In the context of the invention, the release can be triggered by the presence of at least one substance released during fungal development and / or a stimulus generated during such development.

[0047] The term "stimulus generated during fungal development" means any signal or change in the environment induced by the growth and metabolism of fungi. These stimuli may be chemical or physical in nature. Chemical stimuli correspond to substances secreted during fungal development, such as enzymes, secondary metabolites, fungal volatile organic compounds, acids, fungal substances, and / or mycotoxins or a mixture thereof.

[0048] Physical stimuli correspond to changes in environmental properties, such as a change in pH, mechanical action, for example by the growth of hyphae, a change in the structure of the substrate on which the fungi grow or a change in electronegativity that may interfere with the interactions of the constituent elements of the capsule envelope.

[0049] By "secretion," we mean the release of enzymes, acids, fungal volatile organic compounds, or other substances produced by fungi. For fungi, the secretion of these substances indicates fungal development, said secretion occurring prior to the excretion of waste products resulting from their metabolic activities. Organic acids, such as gluconic, citric, oxalic, malic, succinic, and itaconic acids, are produced in varying quantities during the metabolic activity of fungi.

[0050] The term "fungi" refers to organisms with a filamentous lifestyle, meaning that their vegetative structure is composed of filaments called hyphae, which form a network known as the mycelium. Unlike yeasts, which are unicellular fungi, fungi reproduce by means of spores, which are often suspended in the air and can colonize various surfaces. They feed by absorbotrophy, meaning they secrete digestive enzymes into their environment that break down organic matter into nutrients, and then they absorb these nutrients. The mycelium performs several major biological functions, such as exploration, nutrition, growth, and defense. Fungi secrete powerful extracellular enzymes (of the hydrolase type) that allow them to decompose even the most resistant organic matter (for example, wood) by breaking down polymers into monomers.Fungi produce enzymes or acids that contribute to the hydrolysis (notably of starch by Aspergillus niger, Penicillium expansum or of cellulose by Trichoderma, for example) or acidification of the constituents on which they grow. In addition, fungi can cause structural damage to objects and buildings.

[0051] The fungi can be chosen from among micromycetes, such as molds and macromycetes, such as dry rot.

[0052] Examples of micromycete fungi include Aspergillus, Penicillium, Cladosporium, Stachybotrys chartarum, Alternaria, Chaetomium, Fusarium, Trichoderma, Ulocladium, Mucor, Rhizopus, Botrytis, Acremonium, Epicoccum, Geotrichum, Scopulariopsis, Wallemia, Bipolaris, Curvularia, and Phoma. In archive boxes or storage areas with limited ventilation and controlled environments, certain fungi are more prevalent due to the presence of organic materials such as paper, textiles, and adhesives. Common fungi in these environments may include Aspergillus, Penicillium, Cladosporium, Chaetomium, Stachybotrys chartarum (black mold), Alternaria, Trichoderma, Fusarium, Mucor, and Wallemia sebi. Common molds found inside can be Aspergillus, Penicillium, Cladosporium, Stachybotrys chartarum (black mold), Altemaria, Chaetomium, Ulocladium, Acremonium, Fusarium, Mucor.

[0053] Examples of macromycete fungi include dry rots, such as Serpula spp, for example Serpula lacrymans.

[0054] Examples of enzymes secreted (or exocellular) by fungi include hydrolases, such as amylases, proteases, lipases, cellulases, pectinases, and phytases. Amylases are enzymes that break down polysaccharides such as starch and glycogen into simpler sugars like glucose. Fungi can produce amylases to break down starch-rich substrates. Proteases, or proteolytic enzymes, break down proteins into amino acids. Fungi produce these enzymes to digest proteins in their environment, thereby facilitating amino acid absorption. Lipases are enzymes that break down lipids into fatty acids and glycerol. Fungi can produce lipases to break down fats and extract carbon and energy sources.Cellulases break down cellulose, a polysaccharide found in plant cell walls. Fungi produce cellulases to degrade cellulose and access the sugars it contains. Pectinases break down pectin, a component of plant cell walls. These enzymes are produced by some fungi to degrade plant matter. Phytases break down organic phosphate found in phytates, compounds present in seeds and other plant matter. Some fungi produce phytases to release the phosphate bound in these compounds.

[0055] These enzymes allow fungi to colonize and thrive in various environments by breaking down a variety of organic substrates.

[0056] Said at least one compound may be an organic compound, preferably derived from an essential oil. By "compound" is meant a compound that can be encapsulated in microcapsules and that can be selected from a volatile organic compound, an oil, such as a non-volatile oil or an essential oil, a VOC-type tracer, colorant and / or fluorescent agent, a fungicide, a fungistatic agent, or a mixture thereof.

[0057] Thus, the microcapsules may comprise at least one compound selected from a volatile organic compound, an oil, such as a non-volatile oil or an essential oil, a colorant and / or fluorescent tracer, a fungicide, a fungistatic agent, or a mixture of these.

[0058] The tracers, preferably lipophilic, can be dye and / or fluorescent type tracers. Tracers, preferably lipophilic, may be chosen from: rhodamine B, rhodamine 6G, Nile Red, blue food coloring such as Royal sold by Colour Mill, red food coloring such as Red sold by Colour Mill, coumarin 6, DPH (diphenylhexatriene), fluorescein isothiocyanate (FITC), Nile Red, fluorescent lipophilic carbocyanine dyes, such as Dil (1,1'-Dioctadecyl-3,3,3',3'-Tetramethylindocarbocyanine Perchlorate), DiO (3,3'-Dioctadecyloxacarbocyanine Perchlorate), DiD (1,1'-Dioctadecyl-3,3,3',3'-Tetramethylindodicarbocyanine Perchlorate), DiR, DiA, DiB, DiOC18(3), DiOC6(3), DiOC14(3), SP-DiOC18(3), 5,5'-Ph2-DiOC18(3), DilCl(3), DiICl(5), DilCl(7), DilC5(3), DilC12(3), DilC16(3), DilC18(3), DiIC18(3), Dilinoleyl Dil, Neuro-Dil, 5,5'-Ph2-DilC18(3), DilC18(5), DilC18(7), Neuro-DiO,DiA (4-(4-dihexadecylaminostyryl)-N-methylpyridinium iodide), DiB (3,3'-dilinoleyl-3,3'-dimethylindodicarbocyanine), DiOCl(3), DiIC5(3), 6,6'-Ph2-DilC18(3), curcumin, erythrosine (E127), Allura Red (E129), brilliant blue (E133), quinoline yellow (E104), pyronine Y, auramine O, oxazine 170, acridine orange, coumarin 1, coumarin 102, coumarin 153, coumarin 314, coumarin 343, rhodamine 123, rhodamine 110, rhodamine WT, rhodamine 19, Sudan Red I, Sudan Red II, Indocyanine green (ICG), carbocyanine C5, carbocyanine C7, aniline yellow, and aniline blue.

[0059] The term “volatile organic compound (VOC)” refers to a group of organic chemical compounds that transition to a gaseous state under normal (ambient) temperature and pressure conditions due to their high vapor pressure. European Directive 1999 / 13 / EC defines VOCs based on saturated vapor pressure. This directive defines a volatile organic compound as “an organic compound having a vapor pressure of 0.01 kPa or more at a temperature of 293.15 K [i.e., 20 °C] or having a corresponding volatility under particular conditions of use.”

[0060] According to one embodiment, a microcapsule can contain one or more VOCs.

[0061] According to one embodiment, at least one volatile organic compound is chosen including linalool, eucalyptol, cinnamic acid, vanillin, ethyl acetate or mixtures thereof.

[0062] According to one embodiment, at least one volatile organic compound is derived from an essential oil. Such a compound is therefore selected from among the constituent compounds of an essential oil.

[0063] According to one embodiment, at least one volatile organic compound is derived from an essential oil selected from cinnamon, bay leaf, bay laurel, basil or mixtures thereof.

[0064] According to one embodiment, a microcapsule may contain one or more essential oils.

[0065] According to one embodiment, a microcapsule can contain at least two VOCs, each derived from essential oils of different botanical origin. Fungi can exhibit varying levels of sensitivity to VOCs. Thus, according to one embodiment, the microcapsules can encapsulate different VOCs from different botanical origins in order to effectively combat the widest possible range of fungal species.

[0066] According to one embodiment, the essential oil is a cinnamon essential oil that may contain at least seven VOCs: eucalyptol, linalool, cinnamaldehyde, eugenol, cinnamyl acetate, caryophyllene, and benzyl benzoate. The major compound is cinnamaldehyde, which represents approximately 80% of the total mass of VOCs constituting the cinnamon essential oil.

[0067] According to one embodiment, the essential oil is a bay laurel essential oil whose major compounds are eucalyptol, limonene, a-pinene, 13-pinene, sabinene.

[0068] The term “essential oil” refers to oils that contain volatile organic compounds (VOCs) such as terpenes, alcohols, esters, aldehydes, ketones, and phenols. These oils, complex mixtures of VOCs, are known to be used in aromatherapy. Among the VOCs found in essential oils are terpenes, alcohols, esters, and phenols.

[0069] Advantageously, the essential oils may be chosen from among the essential oils of cinnamon, basil, bay leaf, bay laurel, tea tree, lavender, lemongrass, thyme, eucalyptus, clove, oregano, spearmint, peppermint, lemon, lemongrass, palma rosa, rosemary, sage, geranium, niaouli, cedarwood, cypress, patchouli, bergamot, fennel, petitgrain, sandalwood, cedarwood, coriander, agastache, mugwort, bitter mugwort, camphor, Scots pine, lemongrass, sassafras, of chamomile, sage, clary sage, juniper or a mixture of at least two of these.

[0070] Advantageously VOCs derived or not from essential oils can be selected for encapsulation among ethyl acetate, vanillin terpineol, Z or E cinnamaldehyde, cinnamyl acetate, limonene, pinene, linalool, cymene, terpene, campene, campene eugenol, menthol, thujone, caryophyllene, citronellol, sabinene, terpinolene, eugenol, ylangene, pulegone, bomeol,, myrcene, nerol, ocimene, farnesene, d-limonene, a-terpinene, a-pinene, [3-yopinene, 4-terpinene, 3-carene, citral, a-humulene, carvacrol, geranial, isoborneol, y-terpinene, menthone, eucalyptol, [3-myrcene, o-cadinene, a-terpinyl, citronellal, citronellol, cis-carvone, trans-carvone, p-cymerol, cis-ocimene, benzaldehyde, thymol, a-phellandrene, [3-phellandrene, cis-linalooloxide, copaene, [3-cubebene, y-cadinene, santhalene, [3-santhalene, bisabolene, linalyl-acetate, y-muturone, a-tuluene, [3-thugene, gurjune, farnesene, fenchene, muurolene, [3-cephalene,guaiene, y-cadenene, bisabolol, cedrene, copaene, [3-elemene, y-muurolene, bisabolene, cadenene, muurolene, curcumene, gurjunene, [3-curcumene, [3-chamine, segrene, a-bulnesene, [3-bisabolene, [3-guaiene, [3-eudesmol, [3-copaene, a-bulnesene, [3-selinene, [3-chamigrene, [3-bisabolol, [3-bourbonene, [3-selinene, y-molene, [3-cadinene, [3-curcumene, [3-bourbonene, o-cadinene, o-elemene, o-cadinene, o-cadinene, methylbutyrate, 2,2-dimethoxybutane, or mixtures thereof, preferably linalool, eucalyptus, 18-leptolene, cineptol S-limonene, allicin, diallyl sulfide, diallyl disulfide, diallyl trisulfide, thymol, calcium propinate, salicylaldehyde, octanal, octanoic acid, 2-nonanone, [3-benzene-ethanamine, 2-decane-dephthalene, 8, 8, 3 benzaldehyde, y-terpinene, terpinolene, dimethoxydimethylsilane, trimethoxymethylsilane, methyl butyrate, 2,2-dimethoxybutane, toluene d8, toluene, a-thugene,a-pinene, camphene, sabinene, [3-myrcene, cymene, limonene, camphor, ô-Terpineol, borneol, terpinen-4-ol, a-terpineol, naphthalene d8, bomyl acetate, alpha-bergamotene, caryophyllene or mixtures thereof. ,

[0071] According to one embodiment, at least one compound is added to a non-volatile oil. According to one embodiment, at least one volatile organic compound is added to a non-volatile oil.

[0072] By "oil" is meant a compound which has a lipophilic character, that is to say which, when introduced at a content of at least 1% by weight in water at 20°C, is not soluble in water.

[0073] By "non-volatile oil" is meant an oil which generally has a boiling point above 300°C at 101325 Pa and which has little or no vapor pressure at room temperature. Unlike oils Essential oils, non-volatile oils, such as olive oil or coconut oil, are heavier and remain in their state at room temperature without vaporizing.

[0074] Non-volatile oil can be liquid or solid (butter).

[0075] According to one embodiment, the non-volatile oils may be vegetable oils that can be chosen from: sweet almond oil, coconut oil, avocado oil, jojoba oil, olive oil, grapeseed oil, castor oil, argan oil, sunflower oil, sesame oil, pumpkin seed oil, evening primrose oil, borage oil, sea buckthorn oil, apricot oil, raspberry seed oil, safflower oil, walnut oil, pomegranate seed oil.

[0076] According to one embodiment, the non-volatile oils may also be oils of non-vegetable origin which may be selected from: glycerin, propylene glycol or polyethylene glycol (PEG), such as PPG-20 methyl glucose ether 18, PPG-3 methylene benzoate, caprylic / capric triglycerides, dimethicone, cyclopentasiloxane, cyclomethicone, butylene glycol, a mixture of fatty acids or alcohols, such as stearic acid, oleic acid, linoleic acid, cetyl alcohol, cetearyl alcohol, lanolin, jojoba esters, sorbitan tetraoleate.

[0077] Dissolving the volatile organic compound in the non-volatile oil can facilitate a controlled release mechanism. When the microcapsule shell is compromised, for example in response to specific environmental triggers from fungal growth, the volatile organic compound is gradually released.

[0078] It is noted that fungi are also capable of releasing VOCs naturally, called fungal VOCs (or fungal FCOVs). Among the FCOVs generally emitted are alcohols (hexanol, 2-ethyl-Ihexanol, 1-butanol, 3-methyl-l-butanol, 2-methyl-l-propanol, 2-terpineol), terpenes (limonene), sesquiterpenes (thujopsene, cedrene, famesene), ketones (acetonone, butanone, pentanone, 2-hexanone, 3-octanone), furans (pentylfuran), dimethyl disulfide, aldehydes, aromatic compounds (1,3-dimethoxybenzene), ammonia and various amine compounds [7-9]. The study by Schuchardt and Kruse showed that during their primary growth phase, fungi emit low molecular weight FCOVs (alcohols, aldehydes, ketones), which are not very specific, whereas they produce high molecular weight FCOVs at the growth plateau (sesquiterpenes, aromatic hydrocarbons), which have higher specificity [Schuchardt S, Kruse H.Quantitative volatile metabolite profiling of common indoor fungi: relevance for indoor air analysis. J Basic Microbiol 2009;49:350-62]. .

[0079] This intrinsic ability of fungi to release FCOVs does not, however, by itself allow for effective detection. The majority of fungi emit FCOVs are present at very low levels and intermittently, with variations depending on the substrate, making their emission difficult to predict and reproduce. The presence of FCOVs in this disclosure may potentially increase the concentration of VOCs released by the capsules.

[0080] According to one embodiment, the microcapsules do not open in the presence of water. Thus, the microcapsules are not sensitive to the high humidity conditions that may be encountered in certain enclosed environments.

[0081] According to one embodiment, the capsule shell may comprise a mixture of chitosan and a polyanionic substance having an isoelectric point pi greater than or equal to 3.5, preferably greater than 4, preferably between 4.2 and 6.

[0082] By isoelectric point (pi), we mean the pH at which a compound does not carry a net charge, which means that the number of positive charges is balanced by the number of negative charges.

[0083] In acidic conditions, the amine groups (-NH2) of the glucosamine units in chitosan can be protonated to become ammonium groups (-NH3+). This protonation imparts a positive charge to chitosan. The isoelectric point of chitosan can be greater than or equal to 6, preferably between 6.2 and 7. The isoelectric point of chitosan can be influenced by its degree of deacetylation (DD), which is the proportion of free amine groups (-NH2) relative to acetyl groups (-COCH3) in the molecule. A lower DD results in fewer available amine groups, leading to a lower isoelectric point, for example, between 6 and 6.5.

[0084] The polyanionic substance may have an isoelectric point (pI) greater than or equal to 3.5, preferably greater than 4, and preferably between 4.2 and 6. When the pH is above the isoelectric point of the polyanionic substance, it becomes overall negatively charged. At this pH, the carboxylate groups (-COO-) of the acidic amino acids are no longer neutralized by protons, resulting in a net negative charge on the substance. The further the pH moves away from pI towards higher values, the more pronounced the negative charge becomes.

[0085] The polyanionic substance may be a protein extract, the proteins being selectable from those of animal or vegetable origin or a mixture thereof, preferably a milk protein extract, preferably a whey protein isolate. The polyanionic substance having an isoelectric point (pi) greater than 3.5, such as a protein extract, can participate in the formation of the shell during the encapsulation process. Without being bound by any theory, the inventors believe that a protein extract, such as a milk protein extract or a whey protein isolate, which is a polyanionic substance having an isoelectric point (pi) greater than or equal to 3.5, preferably greater than 4, preferably between 4.2 and 6, can interact electrostatically with the polycationic chitosan when the pH is adjusted during the encapsulation process. This interaction improves the structural integrity and stability of the microcapsules and allows for the controlled release of the compound or mixture contained within.

[0086] Without being bound by any theory, a polyanionic substance with an isoelectric point π greater than or equal to 3.5, preferably greater than 4, preferably between 4.2 and 6, such as whey protein isolate, can play a role in the controlled release mechanism of microcapsules. When the microcapsules are exposed to an environment with acidic pH conditions, the whey protein isolate, in conjunction with chitosan, responds to these stimuli. This response can allow for the progressive degradation of the shells and the controlled release of the microcapsule contents. Whey protein isolates, derived from whey (a by-product of cheesemaking), are generally proteins of animal origin. They are biodegradable.

[0087] Whey protein isolate is a highly concentrated form of protein derived from whey. In its isolated form, whey protein is purified to remove most of the carbohydrates (lactose) and fats, leaving mainly proteins, the principal ones being 3-lactoglobulin (isoelectric point of approximately pH 5.2) and α-lactalbumin (isoelectric point of approximately 4.2). This purification is generally carried out by a filtration process that removes impurities and other non-protein components. Whey protein isolate may comprise a protein concentration greater than 80%, preferably greater than 90%, by weight of the total isolate.

[0088] The microcapsules may comprise a ratio between chitosan and the polyanionic substance having an isoelectric point pi greater than or equal to 3.5, preferably greater than 4, preferably between 4.2 and 6, such as the protein extract, for example a milk protein extract or a whey protein isolate, between 10:1 and 1:10, preferably between 5:1 and 1:5, preferably again between 2:1 and 1:2, for example at 1:1. In case of excess or deficiency of chitosan, there is a risk that oil droplets will form on the surface of the outer wall of the microcapsules formed, and therefore that encapsulation will be more difficult.

[0089] Whey proteins may be sensitive to certain enzymes, such as proteases that may be secreted during fungal development.

[0090] According to one embodiment, the microcapsules have a diameter between 1 nm and 100 pm, preferably between 10 nm and 50 pm, or between 1 and 100 pm, or between 1 pm and 30 pm, or between 10 pm and 50 pm, or between 30 pm and 50 pm.

[0091] According to a second aspect, the invention relates to a method for detecting, treating, or preventing fungal growth in an enclosed environment, the method comprising:

[0092] a) the supply of microcapsules according to the first aspect,

[0093] b) the triggering of the opening of microcapsules during the fungal development of fungi,

[0094] c) the release of at least one compound contained in the microcapsules

[0095] d) optionally, the detection of the presence of fungi, and

[0096] e) the inhibition of fungal development of fungi.

[0097] According to a third aspect, the invention proposes a fungal growth detection kit for a closed environment comprising microcapsules according to the first aspect and a detector configured to detect the presence of a compound released by the microcapsules and emit a signal notifying the growth of fungi.

[0098] The compound released by the microcapsules may be a volatile organic compound or a VOC-type tracer, dye and / or fluorescent, preferably lipophilic, an oil, such as a non-volatile oil or an essential oil, a dye and / or fluorescent-type tracer, a fungicide, a fungistatic agent, or a mixture of these.

[0099] A detector configured to detect the presence of a volatile organic compound (VOC) is a device designed to identify the presence and sometimes quantify the levels of these substances in the air. These detectors use various technologies. Among these technologies, the most common are gas chromatography (GC), mass spectrometry (MS), flame ionization detection (FID), UV-Vis absorption spectroscopy, Fourier transform infrared (FTIR) spectrometry, ion mobility spectrometry (IMS), photoionization spectroscopy (PID), photoacoustic spectroscopy (PAS), or electrochemical sensors, particularly those based on electronically conductive polymers (ECPs), semiconductor sensors such as MOS sensors, PID sensors, surface acoustic wave (SAW) sensors, and bulk acoustic wave (BAW) sensors.Quartz crystal microbalances (QCMs), fiber optic sensors, intrinsic fluorescence sensors, induced fluorescence sensors, quantum dot sensors, fluorescent polymer sensors, fluorescent protein-based sensors, thermal conductivity detectors (TCDs) such as hot-wire and micro-hotplate sensors, catalytic sensors, adsorption sensors, piezoelectric sensors, piezoelectric microbalance sensors (microcantilevers), nanostructured material-based sensors, electro-optical sensors, and functionalized RFID chips are used to analyze air samples. and identify the specific VOCs present. VOCs are chemical compounds that can evaporate easily at room temperature and are often emitted by a variety of sources, including consumer products, building materials, and industrial processes. VOC detection is important for monitoring indoor and outdoor air quality, as well as for identifying pollution sources and risks to human health.

[0100] A detector configured to detect the presence of a dye and / or fluorescent tracer is a device designed to identify the presence and sometimes quantify the levels of these substances on the contaminated surface. These detectors use different technologies. Among these technologies, the most common are: the UV detector, the hand magnifier, the binocular magnifier, the USB microscope, the portable digital microscope, the smartphone macro camera, the UV lamp, fluorescence cameras, fluorescent tools (used for leak detection or safety in craft work).

[0101] A detector particularly sensitive to a volatile organic compound (VOC), which can be calibrated to selectively recognize said specific VOC, could make it possible to identify and associate a signal with fungal development. This technology allows for early and accurate detection of fungal infestations in buildings or storage containers, as well as rapid intervention to minimize health risks and property damage.

[0102] According to a fourth aspect, the invention relates to a method for detecting fungal growth in an enclosed environment comprising:

[0103] a) the supply of a detection kit according to the third aspect,

[0104] b) the triggering of the opening of microcapsules during fungal development,

[0105] c) the release of at least one compound contained in the microcapsules

[0106] d) the detection by the detector of the presence of a compound released by the microcapsules,

[0107] e) the emission of a signal by the detector to notify the presence of fungal growth, and

[0108] f) possibly, the inhibition of fungal growth.

[0109] Such a method for detecting fungal growth can be carried out using two indices:

[0110] The inventors have advantageously used the combination of two of these indices to characterize the release of the encapsulated compound and thus develop the fungicidal or fungistatic treatment solution.

[0111] Thus, the ICF (Fungal Contamination Index) allows the detection of fungal activity and the ITL (Localization Tracer Index) allows the localization of fungal development and are used jointly in the following way:

[0112] ICF no / ITL yes: no fungal development (inhibition of fungal development) and detection of the release of compounds having a fungicidal or fungistatic role, thus leading to the cessation of fungal development; such a configuration shows the effectiveness of the treatment to stop fungal development;

[0113] ICF no / ITL no: no fungal development and no release of fungicidal active substances; such a configuration shows the durability of the treatment in the absence of active contamination and fungal development;

[0114] ICF yes / ITL yes: presence of fungal development and detection of the release of compounds having a fungicidal or fungistatic role; such a configuration shows saturation of the treatment and resumption of contamination;

[0115] ICF yes / ITL no: presence of fungal development and absence of release of compounds having a fungicidal or fungistatic role; such a configuration shows an early contamination which has not yet triggered the release of encapsulated compounds and treatment.

[0116] According to a fifth aspect, the invention relates to a method for manufacturing microcapsules according to one of the preceding aspects, the method being able to be phase inversion encapsulation.

[0117] The process for manufacturing microcapsules by coacervation encapsulation may include: - A mixture of the shell constituents comprising chitosan, a surfactant, and optionally a polyanionic substance with an isoelectric point pi greater than or equal to 3.5, preferably greater than 4, preferably between 4.2 and 6, such as a protein extract, for example a milk protein extract or a whey protein isolate, in order to obtain an emulsion, - Dispersion of the emulsion in a continuous, immiscible oily phase to form droplets, - Precipitation of the droplets followed by their recovery and drying.

[0118] The mixing of the components can be carried out by adding each component of the shell to an aqueous phase sequentially, preferably under stirring, possibly at a temperature between 15 and 70°C. For example, homogenization can be carried out at a rotational speed between 5,000 and 25,000 rpm, for example using a homogenizing mill. For example, a Centrifugation can be carried out at a rotational speed between 500 and 15,000 rpm, preferably between 500 and 1000 rpm.

[0119] When adding chitosan, the pH can be adjusted to a value between 5 and 6. The polyanionic substance having an isoelectric point greater than or equal to 4.5, preferably greater than 5, preferably between 4.5 and 6.7, preferably around 6, such as protein extract, for example whey protein isolate, can ideally be added in a mass ratio between 1:10 and 10:1 with respect to the surfactant.

[0120] The constituents may be those described above.

[0121] The surfactant can be chosen from Tween 80, gelatin, acacia gum, xanthan gum, soy protein isolate (SPI) or a mixture thereof. It helps to stabilize the droplets subsequently.

[0122] Phase inversion can be induced by modifying the mixing conditions, which can be accomplished by several methods:

[0123] - Temperature change: Cooling or heating the mixture;

[0124] - Addition of a non-solvent compound, such as an alcohol;

[0125] - Evaporation of the solvent from the components of the envelope, the solvent being Water is preferable.

[0126] The microcapsules can be recovered by filtration, centrifugation, or decantation, followed by washing to remove solvent or non-solvent residues. The microcapsules can then be dried.

[0127] According to one embodiment, the invention relates to a method for manufacturing microcapsules according to one of the preceding aspects, the method comprising: - Stirring an acidic aqueous composition containing chitosan for a period of 100 to 200 minutes at a temperature between 25 and 70°C, followed by adjustment to a pH between 4 and 7, preferably between 5 and 6, - Addition of a surfactant and possibly a polyanionic substance with an isoelectric point pi greater than or equal to 3.5, preferably greater than 4, preferably between 4.2 and 6, such as a protein extract, preferably a whey protein isolate, ideally in a mass ratio between 1:10 and 10:1, to obtain an emulsion, - The emulsion is stirred for a period of 10 to 20 minutes at a temperature between 15 and 35°C. - Addition of a compound, such as an oil, an essential oil, a VOC, a VOC-type tracer, a dye and / or fluorescent agent, preferably lipophilic, or a mixture thereof, and stirring for a period of between 20 and 40 minutes at room temperature, then the addition of an alcohol, such as ethanol, - Homogenization for a period of 5 to 15 minutes at a rotation speed of 5,000 to 25,000 rpm, preferably between 11,000 and 19,000 rpm, using a homogenizing grinder - Centrifugation at 500 and 15,000 rpm, preferably between 500 and 1000 rpm for 5 to 15 minutes at a temperature between 2 and 10°C; - Performing several washes with ultrapure water; - Redispersion in ultrapure water for 12 to 18 minutes; - Drying overnight (approximately 12 hours) in a desiccator or by freeze-drying.

[0128] The encapsulation efficiency makes it possible to determine the quantity of oil encapsulated as a function of the quantity of compound, such as an oil initially present. This parameter is calculated using the following ratio, notably with the aid of UV-visible spectroscopy analysis:

[0129] / pp Oil level detected qq v 7 Initial oil level present

[0130] The EE encapsulation efficiency is improved when the stirring time after the addition of the oil is greater than 20 minutes. The same is true when the pH is adjusted between 5 and 6, where the EE encapsulation efficiency is improved compared to the case where the pH is greater than 7.

[0131] Drying can be done by freeze-drying, allowing the synthesis of microcapsules with a round and intact morphology. Examples

[0132] Example 1. Preparation of microcapsules based on essential oil

[0133] Microcapsules containing an essential oil were prepared according to the following protocol: - Place 60 mg of chitosan (molecular weight between 100 and 300 g / mol, sold by ThermoScientificl) in 20 mL of ultrapure water; - Adjust the pH to 3 with acetic acid (sold by Acros Organics, 99.8% purity) to dissolve the chitosan; - Shake for 150 minutes at 50°C; - Adjust the pH to between 5 and 6 with 2M NaOH at 25 °C; - Add 60 mg of whey protein isolate (sold by Lactalis) and 20 mg of Polysorbate 80 (sold under the reference Tween 80 by Chimie-Plus Laboratoire); - Shake for 15 minutes at 25°C; - Add 80 mg of essential oil; - Shake for 30 minutes; - Add 100 mL of absolute ethanol (sold by Carlo Erba) - Homogenize for 10 minutes at 14,000 rpm using an IKA model Tl8 homogenizing grinder (1 to 1,500 mL and 3,500 to 24,000 rpm); - Centrifuge at 800 rpm for 10 minutes at 4 °C; - Perform several washes with ultrapure water; - Redisperse in ultrapure water for 15 minutes; - Dry overnight in a desiccator.

[0134] This protocol can be applied to different essential oils, of a single botanical origin or of different botanical origins.

[0135] The essential oils used to prepare the microcapsules used in the examples below are cinnamon essential oil (sold by AromaZone) - example 2 and bay laurel essential oil (sold by AromaZone) - example 3.

[0136] Example 2. Evaluation of the inhibitory capacity of microcapsules enclosing cinnamon essential oil

[0137] The objective of this evaluation is to determine whether the microcapsules release the essential oil they contain during fungal growth and whether they succeed in inhibiting the tested strain. To this end, a Fungal Contamination Index (FCI) was calculated. This index assesses the activity of micromycetes using the Volatile Organic Compounds (VOCs) they emit, but, for the purposes of this disclosure, also the VOCs released by the microcapsules. Indeed, VOCs are present from the beginning of fungal growth and throughout all growth phases. Active VOC samples were collected in Tenax tubes. These VOCs were analyzed by gas chromatography and identified using mass spectrometry.In the case of the evaluation, it was necessary to contaminate a material and then place it in a 300 mL glass emission chamber, inert to VOCs, ensuring that the conditions for fungal growth were respected.

[0138] The material that was selected is fiberglass and the strain is Aspergillus brasiliensis (IHEM 05077), from the collection of the Institute of Hygiene and Epidemiology of Brussels - mycology section (IHEM).

[0139] Before contaminating the materials, a culture is grown on oat agar, a rich medium, with incubation at 25°C in the dark for 7 days (Incucell incubator, Fisher Bioblock). After 7 days, a spore suspension is prepared. This is done by collecting the spores developed by the culture using a loop. They are then dispersed in sterile ultrapure water. This suspension is used to contaminate the glass fiber.

[0140] Since fiberglass is an inert medium, it is necessary to enrich the medium to obtain a C / N ratio of 30. The C / N ratio is a molar ratio of carbon (C) to nitrogen (N) in a given environment. To achieve this, the spore suspension is mixed 50% with a nutrient solution (NS).

[0141] The protocol for preparing the nutrient solution (NS) is presented below:

[0142] 1) Preparation of a 100 mL solution of mineral salts in ultrapure water in adding 5g of MgSO4,7H2O and 0.1g of FeSO4,7H2O to obtain a solution 1 of mineral salts.

[0143] 2) Preparation of a 200 mL solution of glucose in ultrapure water in adding 31.5 g of glucose to obtain a glucose solution 2.

[0144] 3) Preparation of a 50 mL NaNO3 solution in ultrapure water by adding 3.71875 g of NaNO3 to obtain a solution of 3 NaNO3. 4) Preparation of IL of nutrient solution by mixing 200 mL of glucose solution 2, 40 mL of NaNO3 solution 3 and 10 mL of mineral salt solution 1.

[0145] Two different SNs were carried out: one containing a buffer at pH = 7.4 and the other without. The buffer is used to verify whether pH can be a stimulus for the release of essential oils.

[0146] Experimental setup

[0147] Six emission chambers (300 mL) were set up, each repeated three times to ensure the repeatability of the results. At the bottom of each chamber, glass beads and 5 mL of pre-sterilized ultrapure water were placed. This ensures humidity saturation inside the chamber, thus allowing fungal growth. Three pieces of fiberglass, cut to dimensions of 2 x 5 cm, were then placed in each chamber, arranged in a U-shape:

[0148] Sample Tl: Place 1 mL of water on the glass fiber, place the glass fiber in a desiccator for 12h, Place 3 pieces of dried glass fiber in an emission chamber, deposit 30 pL of SN nutrient solution at 7 different locations.

[0149] Sample T2: Place 1 mL of microcapsules on the glass fiber, place the glass fiber in a desiccator for 12h, Place 3 pieces of glass fiber soaked with microcapsules then dried in an emission chamber, deposit 30 pL of unbuffered SN nutrient solution at 7 different locations.

[0150] Sample T3: Place 1 mL of microcapsules on the glass fiber, place the glass fiber in a desiccator for 12h, Place 3 pieces of glass fiber soaked with microcapsules then dried in an emission chamber, deposit 30 pL of SN nutrient solution with buffer at 7 different locations.

[0151] Sample Cl: Place 1 mL of water on the glass fiber, place 3 pieces of glass fiber in an emission chamber, contaminate the 3 pieces of glass fiber with 30 pL spots of a mixture of SN and spore suspension for a ratio of 1:1.

[0152] Sample C2: Place 1 mL of microcapsules on the glass fiber, place the glass fiber in a desiccator, place the 3 pieces of glass fiber soaked with microcapsules and then dried in an emission chamber, contaminate the 3 pieces of glass fiber with 30 pL spots of a mixture of unbuffered SN and spore suspension in a 1:1 ratio.

[0153] Sample C3: Place 1 mL of microcapsules on the glass fiber, place the glass fiber in a desiccator, place the 3 pieces of glass fiber soaked with microcapsules and then dried in an emission chamber, contaminate the 3 pieces of glass fiber with 30 pL spots with a mixture of SN with buffer and spore suspension for a ratio of 1:1.

[0154] Once the emission chambers with the glass fiber pieces, contaminated or not, had been prepared, the air inside the chambers was renewed.

[0155] These chambers were then placed in an oven for 7 days. At the end of the 7 days, a sample was taken using a Tenax tube and the same setup, incorporating the chambers that had been left in the oven for 7 days. The Tenax tube traps all VOCs from the filtered air exiting the chamber containing activated carbon.

[0156] The Tenax tubes were then analyzed by chromatography. This analysis made it possible to determine the presence of VOCs related to the growth of the tested strain, as well as those related to the essential oil. For this purpose, monitoring of cinnamic acid (the major component of cinnamon essential oil) was also carried out.

[0157] The analysis parameters used conform to the standards:

[0158] - NF EN ISO 16000-6 (2012): Indoor air - Part 6: Determination of compounds Volatile organic compounds in the indoor air of test rooms and chambers by active sampling on the sorbent Tenax TA(R), thermal desorption, and gas chromatography using MS or MS / FID

[0159] - NF EN 16516 (2017): Construction products: assessment of emissions Hazardous substances - Determination of emissions into indoor air.

[0160] The control and contaminated emission chambers were left for 7 days in an oven at 25 °C. After 7 days, air samples were taken to trap the VOCs present.

[0161] By combining the results of analyses and visual observations, it was possible to conclude regarding the fungal inhibition capacity of cinnamon HE microcapsules ([Fig.2]). Visual examinations confirmed the presence of fungal growth.

[0162] Initial visual observations show that the control chambers do not exhibit fungal growth. These chambers were therefore analyzed and the absence of fungal growth was confirmed (indicated by the "contamination yes / no" box).

[0163] Contaminated chambers not containing essential oil microcapsules exhibit fungal growth, while those containing them, whether with or without pH buffer, do not show fungal growth. This suggests that the microcapsules have released the essential oil. The fiberglass is stained by the contamination, but there is no sporulation, indicating that there is no visible fungal growth. It is also interesting to note that there is no visible fungal growth when the pH buffer (C3) is present. Therefore, a decrease in pH would not be the only factor that allows the release of the essential oil contained in the microcapsules. The release would also result from enzymes secreted by the fungi.

[0164] The addition of nutrient solution and therefore water does not degrade the structural integrity of the microcapsules. In the absence of fungi, no open microcapsules were observed, just as no intact microcapsules were observed in the presence of fungi.

[0165] In all trials where the microcapsules were broken, no fungal growth was observed at 7 days. Only the trial with mushrooms without microcapsules resulted in fungal development.

[0166] In the case of storing documents in archive boxes, for example, this time frame of 7 days is sufficient to protect these documents before the start of fungal development.

[0167] Example 3. Evaluation of the inhibitory capacity of microcapsules enclosing a bay laurel essential oil

[0168] The same protocol as in Example 2 was carried out with microcapsules containing bay laurel oil, with the difference that eight emission chambers were used, including two controls without SN. In the absence of SN, molds could not develop due to a lack of nutrients.

[0169] Sample Tl: Place 1 mL of water on the glass fiber, place the glass fiber in a desiccator for 12h, Place 3 pieces of uncontaminated glass fiber in an emission chamber, deposit 30 pL of SN nutrient solution at 7 different locations.

[0170] Sample T2: Place 1 mL of microcapsules on the glass fiber, place the glass fiber in a desiccator for 12h, Place 3 pieces of glass fiber in an emission chamber and deposit 30 pL of pore suspension at 7 different locations.

[0171] Sample T3: Place 1 mL of microcapsules on the glass fiber, place the glass fiber in a desiccator for 12h, Place 3 pieces of contaminated glass fiber in an emission chamber, deposit 30 pL of pore suspension at 7 different locations, deposit 30 pL of SN nutrient solution at 7 different locations.

[0172] Sample Cl: Place 1 mL of water on the glass fiber, place 3 pieces of glass fiber in an emission chamber, contaminate the 3 pieces of glass fiber with 30 pL spots of a mixture of SN and spore suspension for a ratio of 1:1.

[0173] Sample C2: Place 1 mL of microcapsules on the glass fiber, place the glass fiber in a desiccator, place the 3 pieces of glass fiber soaked with microcapsules and then dried in an emission chamber, contaminate the 3 pieces of glass fiber with 30 pL spots of a mixture of unbuffered SN and spore suspension in a ratio of 1:1.

[0174] Sample C3: Place 1 mL of microcapsules on the glass fiber, place the glass fiber in a desiccator, place the 3 pieces of glass fiber soaked with microcapsules and then dried in an emission chamber, contaminate the 3 pieces of glass fiber with 30 pL spots of a mixture of unbuffered SN and spore suspension in a 1:1 ratio.

[0175] The results are presented in Table 1 below.

[0176] [Tables] Control eSN T1 T2 T3 Control eSNC Cl C2 C3 Nutritive Solution XXXX Suspension of XXXX Spores Microcapsules XXXX Contamination after 7 days (visual inspection) No No No Yes No No No No

[0177] When fungal growth began, open and / or cracked capsules were observed, halting the formation of the mycelial network (unlike the control without capsules). Conversely, in the absence of mold, the capsules did not show cracks. These visual observations therefore demonstrated that the capsules were locally effective.

Claims

Demands

1. Chitosan-based microcapsules for detecting, treating or preventing fungal growth in a closed environment by releasing at least one compound contained in the microcapsules, the release being triggered during fungal growth.

2. Microcapsules according to claim 1, wherein at least one compound is an organic compound, preferably derived from an essential oil.

3. Microcapsules according to claim 2, wherein the essential oil can be selected from cinnamon, bay leaf, bay laurel, basil or mixtures thereof.

4. Microcapsules according to any one of claims 1 to 3 wherein at least one compound can be selected from linalool, eucalyptol, cinnamic acid, vanillin, ethyl acetate or mixtures thereof.

5. Microcapsules according to any one of claims 1 to 4, wherein at least one compound is added in a non-volatile oil.

6. Microcapsules according to any one of claims 1 to 5, wherein the shell comprises a mixture of chitosan and a polyanionic substance having an isoelectric point pi greater than or equal to 3.5, preferably greater than 4, preferably between 4.2 and 6, and preferably said polyanionic substance is a protein extract, preferably a milk protein extract, preferably again a whey protein isolate.

7. Microcapsules according to any one of claims 1 to 6, wherein the microcapsules have a diameter between 1 and 100 pm.

8. Method for detecting, treating, or preventing fungal growth in a closed environment, the method comprising: a) supplying microcapsules according to any one of claims 1 to 7, b) triggering the opening of the microcapsules upon fungal growth, c) releasing at least one compound contained in the microcapsules, d) optionally, detecting the presence of fungi, and e) inhibiting fungal growth.

9. Method according to claim 8, wherein the microcapsules are present in a concentration between 1 and 1000 capsules per cm2.

10. Kit for detecting fungal growth in a closed environment, comprising: - microcapsules according to any one of claims 1 to 7; - a detector configured to detect the presence of a compound released by the microcapsules and to emit a signal notifying the presence of fungi.

11. Method for detecting fungal growth in a closed environment, the method comprising: a) providing a detection kit according to claim 10, b) triggering the opening of microcapsules upon fungal growth, c) releasing at least one compound contained in the microcapsules, d) detecting by the detector the presence of an organic compound by the microcapsules, e) emitting a signal by the detector to notify the presence of fungal growth, and f) optionally, inhibiting fungal growth.

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