Decontamination system

Abstract

The present invention relates to a decontamination system consisting of a worktop and a UV excitation source (5), characterized in that said worktop (1) has an area coated with a vitreous material (4) comprising a phosphor powder. The invention also relates to a method for manufacturing a decontaminating worktop, characterized in that it comprises preparing a mixture of: - ten volumes of water ±10% - three volumes of tetraethyl orthosilicate precursor ±10% - one volume of hydrochloric acid ±10% and then adding, to 10 grams of solution prepared in this way, 1 to 3 grams of phosphor powder, and depositing the vitreous material prepared in this way on the work surface.

Description

Decontamination system Field of invention

[0001] The present invention relates to the fields of bio-decontamination and surface decontamination. It includes applications in the medical sector, for example to combat nosocomial diseases, but also in the pharmaceutical, food and agri-food, space and aeronautical industries.

[0002] Surface decontamination is the process of cleaning and disinfecting surfaces to eliminate, reduce, or kill pathogens, microorganisms, chemical contaminants, or other unwanted substances that may be present on these surfaces. According to NF EN 17272:2020, decontamination is a temporary operation that only concerns contaminants present at the time of the operation. This procedure aims to reduce the risk of spreading disease, infection, or cross-contamination.

[0003] Ultraviolet (UV) radiation decontamination is a decontamination method based on the sensitivity of microorganisms to exposure to wavelengths below 400 nm, particularly UVC radiation emitted between 200 and 280 nm. The mechanism of inactivation of microorganisms by UVC is based on the absorption of UVC photon energy by the nucleic acids of microorganisms, deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).

[0004] This absorption causes structural changes and irreversible damage that will impair the functioning of the host cell. Indeed, the energy of photons emitted between 220 and 280 nm absorbed by nucleic acids is high enough to form a covalent bond between two adjacent bases to the detriment of the initial hydrogen bond. This then results in the formation of mutagenic lesions called pyrimidine dimers, most often thymine dimers in DNA and uracil dimers in RNA.

[0005] These abnormal bonds distort the structure of DNA and RNA, and can disrupt their biological function. They can interfere with replication, transcription, translation, and other biological processes that depend on the integrity of these nucleic acids. The absence of replication or translation causes defects that prevent the microorganism from being viable. In addition to direct modifications to nucleic acids (DNA and RNA), exposure to UV-C radiation (but also UV-B and UV-A, emitted respectively between 280 – 320 nm and 320 – 400 nm) causes oxidative stress and lipid peroxidation. This phenomenon is an indirect aggression linked to the accumulation of reactive oxygen species formed by UVs such as hydroxyl ( - OH) or superoxide (O2 - ). State of the art

[0006] Known in the state of the art is patent application US20150353417 describing a quartz glass member containing a wavelength conversion layer with UV-excitable fluorescent particles. The main purpose of D1 is wavelength conversion (e.g. for LEDs),

[0007] Patent application US20220325176 describes a detection device using a ring scintillator coupled to a bundle of optical fibers to capture ionizing particles. It relates to the detection of radiation.

[0008] Patent application US20210253889 discloses an antimicrobial coating containing doped phosphors, capable of deactivating microorganisms when exposed to a UV-C or UV-B source. This application provides objects including containers receiving the polymeric antimicrobial coating. Disadvantages of the prior art

[0009] The solution proposed by patent application US20210253889 is the only one that mentions the antimicrobial effect, but does not concern the creation of a work surface that must be inert to allow microbiological manipulations. A polymeric material generally has weaknesses in terms of mechanical strength, thermal durability and chemical resistance compared to a glassy material.

[0010] These weaknesses make polymeric surfaces less suitable for a work surface subject to mechanical (friction, loads) or thermal constraints in industrial or medical environments.

[0011] The purpose of the invention is to provide a more efficient UV radiation decontamination system. Polymers are known for their sensitivity to prolonged exposure to UV rays. Over time, this can lead to degradation of the coating (cracking, loss of antimicrobial effectiveness) and a reduction in UV transmission, thus reducing the overall effectiveness of the decontamination system.

[0012] D3's polymeric material does not provide the strength required to maintain stable germicidal properties under constant UV exposure.

[0013] Polymeric coatings often exhibit insufficient adhesion to solid flat surfaces when subjected to frequent washing or chemicals. Solution provided by the invention

[0014] The innovative character provided by the invention consists of the following elements: Simultaneous double UV radiation (excitation and emission, both being germicidal); A UV-transparent surface located between the two radiation sources.

[0015] The invention relates to a decontamination system consisting of a work surface and a UV light source, characterized in that said work surface has an area coated with a vitreous material comprising a phosphor powder. This vitreous material is preferably coated with a UV-transparent protective surface, in particular a quartz sheet.

[0016] For the purposes of this patent, the term "work surface" means a generally horizontal flat surface left free, used for various manual operations using tools.

[0017] This transparent protective surface is advantageously positioned between said vitreous material and said UV excitation source. A work surface used in decontamination systems requires ease of cleaning to ensure constant hygiene, resistance to chemical decontamination products, often incompatible with polymers.

[0018] The transparent UV protective surface is advantageously made of a quartz sheet.

[0019] The invention also relates to a method for manufacturing a decontaminating surface characterized in that it consists of preparing a mixture of: ten volumes of water ±10% three volumes of tetraethyl orthosilicate precursor ±10% one volume of hydrochloric acid ±10%

[0020] then add 1 to 3 grams of phosphor powder to 10 grams of the solution thus prepared and deposit the vitreous material thus prepared either on the work surface (preferably) or on the quartz sheet.

[0021] Detailed description of a non-limiting example of embodiment

[0022] The present invention will be better understood on reading the following description, concerning a non-limiting example of embodiment, illustrated by the appended drawings where:

[0023] represents a schematic sectional view of a worktop according to the invention.

[0024] Controlling surface contamination by microorganisms is a major issue in many sectors, and particularly in the biology laboratory where the intentional handling of dangerous biological agents presents a significant risk of contamination of the workspace and more particularly of the workbenches.

[0025] The use of new processes to kill microorganisms on surfaces is a major focus of public health (fight against bacterial resistance to antibiotics) but also of the individual health of workers (dangerous biological agents). General principle of the invention

[0026] The general principle of the invention relates to a disinfection tool that uses cold plasma technology for the purpose of decontaminating objects and surfaces. The invention is based on the use of a down-conversion type phosphor, i.e. involving a conversion of higher energy photons into lower energy photons (in English "down-conversion"); on the use of excitation radiation emitted by a plasma source as a biocidal agent (in addition to UVC emission radiation); and on the use of a transparent protective surface to protect the coating after deposition on a surface.

[0027] The invention proposes a decontamination system consisting of a work surface and a UV excitation source (5) characterized in that said work surface (1) has an area coated with a vitreous material comprising a phosphor powder (4), said work surface (1) being subjected to simultaneous double UV radiation consisting of said excitation source (5) and a source of emission of said phosphors (4), both being germicidal.

[0028] The inactivation of microorganisms by the synergistic action of excitation (plasma) and emission (luminophore) radiation. Decontamination is achieved by the combination of two UV radiations, denoted R1 (excitation) and R2 (emission). The R1 radiation is emitted by a light source, preferably a light source based on cold plasma, preferably of the excimer lamp type, in the wavelength range 200-300 nm, corresponding to both the germicidal spectrum and the excitation spectrum of a luminophore from which the R2 radiation originates. The R2 radiation is the result of the conversion of the R1 radiation by a luminophore. The luminophore, preferably of the down-conversion type, emits radiation in the wavelength range 200-300 nm after being excited by radiation of a shorter wavelength. The R1 and R2 radiations are germicidal. Example of realization

[0029] Illustrates a schematic cross-sectional view of an example of a worktop. The support (1) is covered with a deposit of phosphors (4) and then with a protective surface (2). Activation of the decontaminating coating requires a plasma source (5) which generates in particular emissions specific to the phosphors used. This plasma source (5) is arranged at a distance from the support (1), without contact with the phosphors, such that its emission field extends over the support (1), typically at a distance greater than 0.5 times the largest dimension of the working surface of the support (1).

[0030] These emissions pass through the protective surface (2) and reach the phosphors (4). Excited by the plasma emissions emitted by the source (5), the phosphors of the coating (4) transform the plasma emissions into biocidal emissions in the 200nm-300nm wavelength range. These biocidal emissions then pass through the protective surface (2) and decontaminate its surface.

[0031] Synergy can also occur by considering the effects of initial plasma emissions directly reaching the outer surface of the shield. The surface of the support is not necessarily flat.

[0032] Method for preparing a decontaminating work surface according to the invention

[0033] As a non-limiting example, the protocol for preparing a vitreous material loaded with luminophores is carried out using a sol-gel method for homogeneous and high-quality deposits.

[0034] For this purpose, a mixture of the following compounds is used: Tetraethyl orthosilicate precursor (TEOS, reagent grade 98%); Water (H2O); Hydrochloric acid (HCl, 37%); Absolute ethanol (99%); Luminophore powder.

[0035] UV-emitting phosphors, for example, belong to the family of phosphors with a composition represented by the formula Ca (2-wxyz) Sr x HAS y Pr z P2O7, in which:A is a 1+ metal cation;w is between 0 and 0.1;x is from 0 to 2-wyz;y is between 0 and 0.25;and z is between more than 0 and 0.12.

[0036] Or to the family including a selected component: in the group (Y 1-x Read x )9LiSi60 26 :Ln ;or in group AE5(P04) 3F:Ln, A, in which Ln is a trivalent rare earth metal, AE is a divalent alkaline earth metal and A is a monovalent alkali metal, x > 0.0 and < 1.0;Luminophores based on strontium aluminates activated by europium and dysprosium ions;Luminophores based on phosphors activated by Eu 2+ (0.0025≤ × ≤0.025) Sr2SiO4:xEu 2+ (SSO:xEu 2+ )

[0037] Or a photoluminescent material known to emit in the 200-300 nm wavelength band.

[0038] Preparation of the gel-luminophore solution for a surface area of ​​25 cm²:

[0039] In a 15 ml tube, add using a micropipette V H2O = 1 ml, V TEOS = 30 µl and V HCl = 10 µl. Shake the tube for 2-3 minutes until a slightly viscous solution is obtained.

[0040] Then 0.2 g of phosphor powder is added to the tube and the tube is shaken again for 2-3 minutes. The phosphor gel solution is then ready to be deposited.

[0041] Deposition of the gel-luminophore solution on the surface:

[0042] The surface of the support (1) is cleaned with ethanol and the residual ethanol is then allowed to evaporate in the ambient air. The previously prepared gel-luminophore solution is deposited in the center of a 25 cm² surface using a micropipette. The gel-luminophore solution is spread with a spatula until a uniform and homogeneous layer is obtained and the gel-luminophore solution is left to dry at room temperature for approximately 1 hour. The surface is ready as soon as the deposit is completely dry.

[0043] The transparent protective material is cleaned with ethanol and then the residual ethanol is allowed to evaporate into the ambient air.

[0044] A transparent protective material, such as a sheet of quartz, silica, magnesium fluoride (MgF2) or calcium fluoride (CaF2), or any UVC-transparent polymer, is then gently placed on the dry phosphor sol-gel deposit. The edges of the transparent protective material are sealed with silicone (3).

Claims

Decontamination system consisting of a work surface (1) and a UV excitation source (5), characterized in that said work surface has an area coated with a vitreous material comprising a luminophore powder (4), said powder being excited by UV radiation (R1) to emit secondary germicidal radiation (R2). Decontamination system according to claim 1 characterized in that said vitreous material comprising a luminophore powder (4) is coated with a UV-transparent protective surface (2). Decontamination system according to claim 2 characterized in that said UV transparent protective surface (2) is positioned between said vitreous material comprising a phosphor powder (4) and said UV excitation source (5). Decontamination system according to claim 2 characterized in that said UV-transparent protective surface (2) is constituted by a quartz sheet. Method for manufacturing a decontaminating work surface characterized in that it consists of preparing a mixture of: ten volumes of water ±10% three volumes of tetraethyl orthosilicate precursor ±10% one volume of hydrochloric acid ±10% then adding to 10 grams of solution thus prepared 1 to 3 grams of luminophore powder (4) and depositing the vitreous material comprising said luminophore powder (4) thus prepared on a work surface (1).

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