Device for spraying a functional coating of supramolecular structures

Abstract

The invention relates to a device (100) for spraying a functional coating of supramolecular structures onto a surface, characterised in that the device comprises at least two vessels, a first vessel (106) which is able to receive a first polycation solution, and a second vessel (107) which is able to receive a second polyanion solution, at least a first nozzle (156) and a second nozzle (157) for spraying the first polycation solution and the second polyanion solution, respectively, the flow of the first and second solutions in a first and a second flow channel, respectively, formed between the first and second vessels and the outlet opening (156B, 157B) of the first and second nozzles, being caused by pressure applied to the solutions in their relevant vessel, and the first and second flow channels respectively have at least one section of conical shape such that their diameter decreases by a predetermined factor F.

Description

[0001] Device for spraying a functional coating of supramolecular structures

[0002] The present invention relates to the field of functional coatings obtained by spraying solutions of supramolecular structures, such as polyelectrolyte solutions. Such coatings can be used both in the medical field and in the cosmetic field or more generally in any field involving a functional coating of surfaces. The invention relates more particularly to the spraying of polyelectrolyte solutions for the application of a functional coating of supramolecular structures on the human body and on any surface intended to be in contact with the human body.

[0003] In the medical field, the coatings envisaged include coatings with antiviral, antifungal, anti-inflammatory and / or antimicrobial activity. In the example of coatings with antimicrobial activity, these can be used to cover any type of surface such as medical instruments, invasive or not, or the surface of implants for example, in order to prevent any type of nosocomial infection. Such antimicrobial coatings can also be sprayed onto living surfaces or biological structures such as the skin, in order to treat a wound for example by spraying a layer of barrier coating, like a "liquid bandage".

[0004] Among the various possible industrial applications, the invention also relates, in a non-exhaustive manner, to the cosmetic field. Thus, antimicrobial functional coatings may also be sprayed onto manufacturing equipment or onto surfaces that come into contact with cosmetic products. The cosmetic field also relates to the spraying of other types of functional coatings having activities other than antimicrobial activity. Thus, for example, functional coatings for improving hair conditioning may also be sprayed onto the hair, for example to strengthen it or improve its shine or suppleness. Other functional coatings may be sprayed onto the skin to improve its elasticity, or to protect it against insect bites, for example.

[0005] The applicant was initially interested in the medical field and for this purpose developed antimicrobial functional coatings from polyelectrolytes as well as a process for producing such coatings. Patent applications WO2017 / 191110; US2018 / 0318472 and WO201 9 / 086618 describe such coatings obtained by successive and alternating dipping of the surface of an object to be coated in solutions of polycation and polyanion respectively. The surface material of the object to be coated can be chosen from all kinds of materials. It can thus be made of a metal such as titanium for example, a polymer such as silicone for example, a ceramic or another material such as wood for example.The successively deposited layers of polycation and polyanion interact supramolecularly and form a polyelectrolyte network in which the different layers are linked together by van der walls type bonds, hydrogen bonds or electrostatic and / or hydrophobic interactions.

[0006] Promising biocompatible polyelectrolytes for coating medical implants have been specifically studied. The polycations studied are, for example, chosen from poly-L-arginine (PAR), poly-L-lysine (PLL), poly-epsilon-lysine (EPLL) or poly-L-ornithine (PLO) with chains ranging from 10 to 200 monomer units. The polyanion chosen is hyaluronic acid (HA) or one of its derivatives, or lambda, kappa or iota carrageenans and their derivatives. In one example, the polycation polyarginine 30 (PAR30), i.e. comprising 30 units of the arginine monomer, and the polyanion hyaluronic acid (HA) are applied by successive dipping up to 24 bilayers to form an antimicrobial functional coating. The growth of the polyelectrolyte coating layer by layer follows a growth that allows the diffusion of one of the polyelectrolytes inside the coating. Such a coating is said to be "diffusive".The coating thus formed allows the mobility of the polycation to be maintained in the polyelectrolyte network and its associated antimicrobial active ingredient.

[0007] Such a coating can be applied to implants before surgery to prevent the occurrence of infection and therefore reduce the number of nosocomial infections.

[0008] The current coating application method is by robotic dipping. For this, several bilayers (up to 24 for example) are applied to the surface of the object to be coated to obtain the desired functional coating. A bilayer consists of the adsorption of a polycation layer followed by a polyanion layer or vice versa. The coating application method is carried out according to the following protocol. A first step consists of cleaning the surface of the object to be coated. Such cleaning consists, for example, of placing the object to be coated in an alkaline detergent solution, marketed under the registered trademark Hellmanex at 2%, for 15 minutes, then placing it in distilled water for 15 minutes and finally placing it in a 100% ethanol solution, all in an ultrasonic bath. The object is then dried with compressed air.Subsequently, the object is alternately dipped in a first tank containing a solution of a first polyelectrolyte, for example the polycation, then rinsed in a second tank containing a buffer solution, then dipped in a third tank containing a solution of a second polyelectrolyte, for example the polyanion, and finally rinsed in a fourth tank containing a buffer solution. These dipping and rinsing steps are repeated as many times as necessary until the desired coating with the required number of bilayers is obtained. During each dipping a small amount of polyelectrolyte is adsorbed and the charge of the object surface is reversed, allowing the gradual and controlled construction of a diffusive polyelectrolyte coating, in which the polycation can retain its mobility and its associated antimicrobial active ingredient.Rinsing in a buffer solution between each deposition of polyelectrolyte layer makes it possible to eliminate the polyelectrolyte residues not adsorbed on the surface of the object and to avoid the formation of precipitates or micelles responsible for a reduction in the quality of the final coating.

[0009] The polycation solution is for example made from polyarginine PAR30, and the polyanion solution is for example made from Hyaluronic acid (HA). The polycation and the polyanion are respectively dissolved at a concentration of 0.5mg.mL-1 in a sterile buffer solution containing 150mM sodium chloride (NaCl) and 10mM tris(hydroxymethyl)-aminomethane (TRIS) whose pH is adjusted to 7.4. When all the layers have been alternately deposited, the resulting coating is dried under compressed air then immersed in a NaCl / TRIS buffer solution and stored at 4°C before use.

[0010] The current method of layer-by-layer deposition by robotic dipping has several drawbacks. The deposition time can be long and not compatible with certain applications. Typically, it can be between 30 minutes and 13 hours depending on the size of the object to be coated. The cost of maintaining the baths is also significant, especially since this method involves a lot of waste since the polyelectrolyte solutions contained in the tanks are discarded after each treatment and cannot under any circumstances be reused to deposit a coating on another object. This method also requires having equipment correctly sized in relation to the size of the object to be treated, and in particular equipment whose dimensions allow it to contain enough tanks and whose rinsing and polyelectrolyte tanks must be of a size adapted to the object to be treated.

[0011] Furthermore, this layer-by-layer deposition method limits applications since it does not allow such a coating to be applied to the skin (directly on oneself), for example, to treat a "fresh" wound by applying a barrier coating, nor to apply such a coating to objects that are not compatible with the dipping process due to the size, shape, or sensitivity to humidity of the object, for example.

[0012] To solve the problems associated with this dipping method, the applicant has been interested in other coating methods, in particular the spray-on method. Such a method appears promising because it allows a transition from application by stationary device to application by mobile device, which allows application on different types of objects not compatible with the dipping process and on living or non-living surfaces that can serve as fomites. Such a spray-on method also allows in situ coating applications. Finally, spraying the polyelectrolyte solutions directly onto the surface of an object makes it possible to use only the necessary quantity of product and to avoid waste by discarding significant quantities of solutions used for dipping baths.

[0013] The applicant therefore carried out some tests to test this spraying method. It turns out that the use of a conventional spray with a simple spray does not give the expected results. Indeed, the polyelectrolyte solutions, being mixed together at usual concentrations for this type of coating before being sprayed, tend to polymerize together before reaching the spray nozzle. Said polyelectrolyte solutions then form an insoluble complex leading to obstruction of the spray nozzle feed pipe, the production of a non-homogeneous and non-uniform polymerized coating on the surface of the object to be coated and a heterogeneity of the concentration of active ingredients, which causes a loss of activity, due to the loss of mobility of the polycation in the polymer network formed.In such a conventional spraying device, the polyelectrolytes interact with each other, so that their charges are no longer available to allow interactions with the substrate.

[0014] The applicant then sought a means of being able to spray, simultaneously onto a substrate, the polycation and polyanion solutions via two separate spray nozzles, in such a way that the polycation and the polyanion mix at the outlet of the spray nozzles and the mixture thus formed is deposited in a reaction functional layer, via a supramolecular interaction between the inversely charged molecules, on the surface of the object to be coated.

[0015] There are dual-nozzle spray devices on the market. For example, there is an oil and vinegar sprayer, marketed under the registered trademark Aubecq, comprising two separate compartments, each intended to receive oil and vinegar respectively. This dual-nozzle sprayer includes a first nozzle with a small hole for depositing the oil evenly on the food, and a second nozzle for spraying a mist of vinegar. An adjustment ring is used to select the proportion of oil and vinegar to be sprayed. This sprayer allows two separate products to be sprayed onto food, but it does not allow them to be mixed at the nozzle outlet, so that they interact with each other to form a coating.

[0016] Other devices for spraying two products exist on the market. For example, there are 2-nozzle sprayers in the hairdressing sector, for spraying hair styling products such as texturizing sprays or fixatives, or volumizing products combined with fixatives. Such a spray device could, for example, be used to apply, by spraying, a polyurethane polymer in solvent and silver nitrate particles to the hair. In this case, the intended application concerns the application of polymerized particles to the hair to improve its volume and shine. For example, the company Schwarzkoft offers a dual-nozzle device, marketed under the registered trademark Got2b, for applying a double-finishing wax depending on whether the user wants a flexible texture or a structured hold for their hair.This type of device does not concern the production of a functional coating layer of supramolecular structure which would be deposited on the hair.

[0017] Finally, there are comb-shaped applicators with two flexible reservoirs. These applicators allow the application of two products to the hair, in order to achieve coloring and / or hair care simply and easily. Such devices comprise two reservoirs intended to respectively receive two liquid or viscous products to be applied. Each reservoir is connected to a comb-shaped tip. The teeth of the comb-shaped tip are pierced with small holes connected respectively to each reservoir, to allow the application of the two products simultaneously, efficiently and evenly on the hair. The application of the products to the hair consists of exerting pressure on the flexible reservoirs to allow the products to flow towards the comb-shaped tip.This type of applicator is not suitable for depositing a functional coating of polyelectrolytes since the products are not mixed at the nozzle outlet but are deposited next to each other on the hair. In addition, the products are not sprayed in this case, but rather applied to the surface of the hair, upon contact. The application of this type of device is not intended for the two products to interact with each other to form a reaction functional layer intended to form a functional coating on the hair. The hair applicators just described are also not compatible with medical sterilization processes.

[0018] Document US 2004 059283 A1 also describes a device for spraying biocompatible material onto a surface, making it possible to deposit one or two biocompatible materials via a pressurized medical gas, using a regulation system for regulating the gas flow and pressure. The regulation system comprises two switches and allows a selection from four preset positions depending on whether one and / or two materials are to be deposited under high medical gas pressure and / or under low medical gas pressure. However, said document does not describe the possibility of fragmenting the polyelectrolyte solutions into fine droplets to enable a homogeneous aerosol suspension to be obtained at the nozzle outlet.Furthermore, spraying a solution under high gas pressure cannot be considered for covering a living surface, particularly when applying a coating to a wound, due to the pain that such high pressure can cause. US 11,806,740 describes an electrostatic applicator device for applying one or more solutions to a treatment surface of a patient. This device comprises a high-voltage module intended to apply an electric field to the solution(s) to be applied. This electric field makes it possible to charge the solution positively or negatively to create a difference in polarity that generates an attraction between the applied solution and the treatment surface. The electric field also makes it possible to fragment the solution into tiny droplets, of a size of the order of a micron, allowing a uniformly distributed treatment layer to be obtained.Such a device is complex in construction and expensive to manufacture.

[0019] The existing devices on the market are therefore not entirely satisfactory and do not allow the deposition by spraying of a functional coating of polyelectrolytes on any surface.

[0020] The invention therefore aims to remedy at least one of the drawbacks of the prior art. The invention aims in particular to propose a device for spraying a functional coating of supramolecular structures onto a surface of the human body or a surface which may be in contact with the human body, which allows simultaneous spraying of two polyelectrolytes of opposite charges, requiring a conjugated and metered interaction with each other, in order to obtain a reaction functional layer via a supramolecular interaction between the molecules charged in the opposite manner. The conjugated interaction between the two polyelectrolytes must be able to take place at the outlet of two spray nozzles in order to avoid the formation of a residual highly aggregated complex in a spray nozzle.The reaction functional layer formed must also be able to remain soluble and not alter the usual behavior of the polyelectrolytes, that is to say it must allow the conservation of the mobility of the polyelectrolyte ensuring the activity of the active ingredient, for example the mobility of the polycation in the case of an antimicrobial coating. For this, the reaction layer must be formed by supramolecular interaction and not by polymerization. This interaction also depends on the homogeneity of the aerosol suspension at the nozzle outlet, and in particular on the size of the suspended droplets. The invention therefore also aims to control the spraying at the nozzle outlet to allow this combined interaction of the two polyelectrolytes. Finally, the spraying must be able to be carried out at low pressure to avoid any occurrence of pain when it is carried out on a surface of the human body.The device must also be easily sterilizable to be able to be used in medical applications.

[0021] To this end, the invention relates to a device for spraying a functional coating of supramolecular structures onto a surface, comprising at least two reservoirs, a first reservoir capable of receiving a first solution of a polycation and a second reservoir capable of receiving a second solution of a polyanion, at least a first and a second nozzle for spraying respectively the first polycation solution and the second polyanion solution, the flow respectively of said first and second solutions in a first and a second flow channel, formed between said first and second reservoirs and the outlet orifice of said first and second nozzles, being caused by a pressure exerted on said first and second solutions in their respective reservoir,said device being characterized in that said first and second flow channels respectively have at least one conical section so that their diameter decreases, from said first and second reservoirs to the outlet orifice of said first and second nozzles, by a factor F strictly greater than one and chosen so as to cause fragmentation of said first and second solutions under pressure into droplets.,

[0022] Thus, the two polyelectrolytes of opposite charges are mixed directly at the outlet of the spray nozzles. The reduction in the diameter of the flow channel of the polyelectrolyte solutions combined with the pressure exerted on said solutions, forces the solution to fragment into fine droplets. The device according to the invention thus allows constant spraying of the two polyelectrolyte solutions, and the obtaining of a homogeneous aerosol suspension, the droplets of which have a diameter substantially less than 100 pm, and to avoid the formation of aggregated complexes likely to cause defects in the final coating. Such a homogeneous suspension promotes the supramolecular interaction between the two polyelectrolyte solutions of opposite charges and a uniform and homogeneous coating deposition on the surface, in which the mobility of the polyelectrolyte ensuring the activity of the active ingredient is preserved.

[0023] According to other optional characteristics of the device: the factor F of reduction of the diameter of said first and second flow channels is between 2 and 16, preferably between 4 and 8; each spray nozzle is connected respectively to the first and second reservoir via an adapter comprising a conduit forming said conical section respectively of said first and second flow channel; the pressure exerted on said first and second solutions in their respective reservoir is a mechanical pressure exerted respectively by a first and a second piston; the first and second pistons are connected to each other by a first push button making it possible to exert simultaneous pressure on said first polycation solution and second polyanion solution and to cause their simultaneous spraying;the device comprises a third reservoir and a third spray nozzle, said third reservoir being capable of receiving a third solution, said third solution flowing in a third flow channel, formed between the third reservoir and the outlet orifice of the third spray nozzle, under the action of mechanical pressure exerted on said third solution in its reservoir by a third piston and the device comprises a second push button capable of exerting pressure on said third piston to allow the flow of said third solution towards said third spray nozzle;the device comprises a motor powered by a battery and enabling to actuate an air pump intended to inject air, via at least a first and a second air flow pipes, into said at least first and second reservoirs, and said first and second solutions flow respectively in a first and a second flow pipe towards their respective spray nozzle, under the effect of the pressure exerted by the injected air;the device comprises a third reservoir and a third spray nozzle, said third reservoir being adapted to receive a third solution, said third solution flowing in a third flow pipe towards the third spray nozzle, under the action of a pressure exerted on said third solution in its reservoir by air injected, via a third air flow pipe, into said third reservoir by means of said air pump; the third solution is a cleaning solution or a solution comprising active agents;each spray nozzle comprises two inlet orifices and one outlet orifice: a first inlet orifice being connected to the flow pipe of one of said first or second solutions and extending by a first conduit, forming the conical section of one of said first or second flow channels and opening into a mixing chamber located upstream of the outlet orifice, and a second inlet orifice being connected to a third air flow pipe and extending by a second conduit opening into said mixing chamber in which said first or second solution and the pressurized air mix before being sprayed through the outlet orifice; the mixing chamber is preferably located at a distance less than or equal to 2.5 mm from the outlet orifice of the spray nozzle;the device further comprises a pressure sensor intended to measure the pressure of air injected by the air pump, said pressure sensor addressing the measured pressure value to a microprocessor capable of acting on a valve to adjust the pressure to a pre-recorded setpoint value; the device further comprises at least a first and a second flow meter capable of measuring the flow rate respectively of the first polycation solution and of the second polyanion solution flowing respectively in their respective flow pipe, towards their spray nozzle, said measured flow rate values ​​being addressed to a second microprocessor capable of acting on a selector to adjust said flow rate values ​​to pre-recorded setpoint values;the selector is in the form of a set of valves, each valve being located respectively in the first and second flow pipes of said first and second solutions, the opening or closing of said valve being controlled by said second microprocessor; the flow pipes of said first and second solutions are made of a flexible material; and the selector is in the form of a switch button capable of sliding between two end positions and of pinching one and / or the other of the flow pipes of said first and / or second solutions; the flow pipes are made of an elastomer material chosen from silicones, polydimethylsiloxane (PDMS), polyurethane (PU) or low density polyethylene (LDPE);the device comprises a trigger capable of actuating the motor which drives the air pump to inject the pressurized air into the first and second reservoirs and cause simultaneous spraying of said first polycation solution and second polyanion solution; the device comprises a second trigger capable of actuating the motor which drives the air pump to inject pressurized air into the third reservoir and allow spraying of said third solution; the device further comprises a human-machine interface, in the form of a touch screen connected to a third microprocessor and to a memory, making it possible to configure the set values ​​of the air pressure and the flow rate of said solutions; the first, second and / or third microprocessors may be combined;an electronic unit, comprising the motor, the air pump, the battery, the microprocessor(s) and at least one memory, is arranged in a removable housing intended to be separated from the device during cleaning, disinfection and sterilization operations; the pressure of the air injected by the air pump is preferably between 0.8 and 2 bars; each reservoir is sized for a spray volume which may be between 0.5 and 10 milliliters.;

[0024] The invention further relates to a method for spraying a functional coating of supramolecular structures onto a surface, using the device described above, characterized in that it comprises the steps of targeting the surface to be sprayed, maintaining the device at a distance d from the surface of between 5 and 15 centimeters, and simultaneously spraying the polyelectrolyte solutions onto said surface, under a pressure of less than 2 bars, said spraying being able to be carried out continuously on several layers.

[0025] According to other optional characteristics of this method: the number n of layers is preferably between 1 and 24; a step prior to the step of spraying the polyelectrolyte solutions consists of spraying a cleaning solution onto said surface; a step subsequent to the step of spraying the polyelectrolyte solutions consists of spraying a solution containing active agents onto the previously sprayed coating layer; the distance d between the nozzles of the spraying device and the surface is advantageously between 5 and 25 centimeters, preferably between 5 and 15 centimeters; the surface onto which the functional coating of polyelectrolytes is sprayed is a material chosen from living surfaces: for example skin, hair or non-living surfaces: for example glass, titanium, silicone, ceramic, wood;the polycation may be chosen from poly-L-arginine (PAR), poly-L-lysine (PLL), poly-epsilon-lysine or poly-L-ornithine (PLO) and in that the polyanion may be chosen from hyaluronic acid, alpha, lambda and kappa carrageenan, alginate or one of their derivatives.;

[0026] Other features and advantages of the invention will appear on reading the description given by way of illustrative and non-limiting example, with reference to the appended figures which represent:

[0027] - Figures 1A and 1B respectively illustrate an exploded perspective view and a side view of a device according to a first embodiment;

[0028] - Figures 2A and 2B illustrate a longitudinal view and a sectional view AA of an adapter intended to connect to an inlet orifice of a spray nozzle of the device according to the first embodiment;

[0029] - Figure 3 illustrates an exploded perspective view of a spray device according to the first embodiment intended to be used for applying a functional coating to the skin;

[0030] - Figure 4 illustrates an exploded perspective view of a spray device according to the invention intended to be used for applying a functional coating to the hair;

[0031] - figure 5 illustrates a simplified diagram of a device according to a second embodiment;

[0032] - Figure 6 illustrates a sectional diagram of a spray nozzle with two inlet orifices and one outlet orifice used in the device according to the second embodiment;

[0033] - figure 7 illustrates a semi-exploded perspective view of a device according to the second embodiment;

[0034] - figure 8 illustrates a partial sectional view of the device of figure 7;

[0035] - figure 9 illustrates a sectional view of a selector in 3 different positions;

[0036] - Figure 10 illustrates cross-sectional images of different sprayed coatings, taken with a confocal laser scanning microscope; - Figures 11 A, 11 B and 11C illustrate graphs demonstrating the inhibition of S. aureus growth on coatings sprayed on three samples (E, F, G), from the same polyelectrolyte composition, respectively on a glass substrate, a silicone substrate and a titanium substrate;

[0037] - Figures 12A, 12B, 12C and 12D illustrate graphs demonstrating the inhibition of the growth of P. aeruginosa, E. Coli and S. aureus respectively on coatings sprayed on three samples (A, B, C or E, F, G), from another polyelectrolyte composition, on a silicone or glass substrate;

[0038] - Figures 13A, 13B, 13C and 13D illustrate graphs demonstrating respectively the antibacterial efficacy of a sprayed coating in vivo, and the in vivo behavior of such a sprayed coating on wounds.

[0039] By "polymer" we mean a macromolecule, organic or inorganic, that is to say a chain of repeating constituent units, called monomers.

[0040] The term "polyelectolyte" as used refers to a polymer having ionizable groups in a polar solvent.

[0041] The term "polycation" as used refers to a polyelectrolyte whose repeating units, or monomers, are positively charged. A polycation is produced as a salt with a counterion. The counterion may be selected from, but is not limited to, hydrochloride, hydrobromide, or trifluoroacetate.

[0042] The term "polyanion" as used refers to a polyelectrolyte whose repeating units, or monomers, are negatively charged. A polyanion is produced as a salt with its counter ion, such as sodium hyaluronate salt.

[0043] The term "functional coating" means a coating in which active ingredients enable the coating to perform a function. The term "functional coating of supramolecular structures" means a layer of functional coating formed by supramolecular interaction between molecules, for example polyelectrolyte molecules, which are inversely charged. The supramolecular interactions may be of the Van der Walls type and / or of the hydrogen bond type and / or result from an electrostatic and / or hydrophobic interaction. The supramolecular interactions enable the mobility of one of the polyelectrolytes, the support for the active ingredient, to be maintained, enabling the coating to perform a function.

[0044] The term "mobility" of the polyelectrolyte, for example the polycation, refers to the fact that the polycation chains are mobile within the thickness of the coating. This mobility is possible due to the supramolecular interaction and the so-called "diffusive" growth mode of the coating film, allowing the polyelectrolyte chains to diffuse within the coating. Covalent bonds between the layers would not allow the polyelectrolyte to remain mobile within the coating.

[0045] A "buffer solution" is an aqueous solution consisting of a mixture of a weak acid and a weak conjugate base. Such a solution is used to maintain the pH at a substantially constant value for a wide variety of applications. In the context of functional polyelectrolyte coatings, such a buffer solution can be formed, for example, with PBS (Phosphate buffered saline) or TRIS (tris(hydroxymethyl)aminomethane).

[0046] The term "spray" within the meaning of the invention consists of a dispersion of an aerosol.

[0047] An "aerosol" is defined as a suspension of particles, of a substance or of a mixture of substances, in a gaseous medium such as, for example, air. According to the invention, the particles of the aerosol suspension must have a sufficiently small diameter, i.e. substantially less than 100 pm and preferably less than 80 pm. Larger droplets are likely to lead to the formation of aggregated complexes and the appearance of defects in the deposited coating. Controlling the spraying, i.e. the size of the suspended droplets, makes it possible to obtain a uniform mist suspended in the air, to better control the proportion of the two polyelectrolyte solutions relative to each other at the nozzle outlet and to promote the supramolecular interaction between the two polyelectrolytes ensuring that a uniform coating is obtained.

[0048] First mechanical embodiment:

[0049] Figure 1A illustrates an exploded perspective view of a first embodiment of a functional coating spray device for polyelectrolytes according to the invention. Figure 1B illustrates a side view of the device of Figure 1A.

[0050] According to this first embodiment, the device comprises a housing 100 whose shape can vary depending on the use for which it is intended, without departing from the scope of the invention. In the example illustrated in Figures 1A and 1B, the housing 100 comprises a main body 101 and a handle 102, substantially perpendicular to the main body, to facilitate its handling. The main body 101 is intended to receive at least two reservoirs 106, 107, respectively containing polycation and polyanion solutions to be sprayed. The first reservoir 106 is intended to contain a first polyelectrolyte solution, for example a polycation solution, while the second reservoir 107 is intended to contain a second inversely charged polyelectrolyte solution, i.e. a polyanion solution in the example.Each of the internal side walls of the main body 101 is provided with at least two stiffeners 103, the stiffeners 103 of one wall being arranged opposite the stiffeners of the other wall. Each stiffener 103 comprises a notch 104 whose shape is complementary to that of a reservoir. The stiffeners 103 make it possible on the one hand to reinforce the hollow structure of the main body 101 and on the other hand to fix a reservoir in each notch 104.

[0051] The first and second reservoirs 106 and 107 are placed side by side in the main body 101 and are fixed respectively in the notches 104 of the lateral stiffeners 103 of the main body 101. The first polycation solution and the second polyanion solution flow respectively from the first reservoir 106 and the second reservoir 107 towards respectively a first nozzle 156 and a second spray nozzle 157. This flow is caused by a pressure exerted simultaneously on said solutions in their respective reservoir. In the non-exhaustive example of FIG. 1A, said reservoirs 106, 107 have a syringe shape.Each of the reservoirs 106, 107 is provided with a piston 116, 117 which, when actuated, makes it possible to exert mechanical pressure on the solution contained in the reservoir and cause it to flow in a flow channel formed between the reservoir and the outlet orifice 156B, 157B of the spray nozzle 156, 157. Advantageously, each flow channel for each solution has at least one conical-shaped section making it possible to reduce its diameter, from the reservoir 106, 107 to the outlet orifice 156B, 157B of the nozzle 156, 157, by a predetermined factor F. The pistons 116, 117 are not housed in the main body 101, but protrude from the latter by the rear end, opposite the spray nozzles 156, 157, so that said pistons are accessible to a manipulator in order to be able to exert pressure thereon. The pressure exerted by the actuation of the pistons is less than or equal to 2 bars.Such reservoirs and pistons are preferably made of a material compatible with medical and / or cosmetic applications. This material may, for example, be medical-grade polyethylene or polypropylene.

[0052] Preferably, each spray nozzle 156, 157 can be connected to each reservoir via an adapter 200. This adapter 200 comprises a conduit 212 forming the conical section of the solution flow channel between the reservoir 106, 107 and the outlet orifice 156B, 157B of the nozzle 156, 157.

[0053] Figures 2A and 2B respectively diagram a longitudinal view and a sectional view AA of the adapter 200.

[0054] This adapter 200 comprises two end pieces 210, 215. A first end piece 210, with its inlet orifice, is capable of being fixed to the outlet orifice of the reservoir 106, 107, opposite the piston 116, 117. For its fixing, it comprises for example a thread 211. Its second end 215, with its outlet orifice, is intended to be fixed in the inlet orifice 156A, 157A of the spray nozzle 156, 157. The inlet orifice is defined as the orifice through which the solution flows into the nozzle 156, 157 before being sprayed into the air through the outlet orifice 156B, 157B. This adapter 200, as illustrated in FIG. 2B in section AA, comprises a conduit 212 in which the solution to be sprayed flows. The shape of the conduit 212 is substantially conical so that the diameter of its inlet orifice 210 is greater than the diameter of its outlet orifice 215. In FIG. 2B, the conduit 212 is in the form of three successive cones.This conduit 212 may however take any other conical shape without departing from the scope of the invention, provided that its diameter decreases progressively between the inlet orifice 210 and the outlet orifice 215. Advantageously, the reduction in the diameter of the conduit 212, between its inlet orifice 210 and its outlet orifice 215, decreases by a factor of between 2 and 15, preferably between 3 and 7. Such a conical section 212 makes it possible to reduce the diameter of the flow channel, formed from the outlet orifice of the reservoir 106, 107 to the outlet orifice 156B, 157B of the nozzle 156, 157, by a predetermined factor F. This predetermined factor F of the reduction in the diameter of the flow channel may for example be between 2 and 16, and preferably between 4 and 8.Such a reduction in the diameter of the flow channel of the solution to be sprayed, combined with the pressure exerted on said solution, makes it possible to force the liquid to fragment into fine droplets to obtain, at the outlet of the spray nozzle 156, 157, droplets whose diameter is substantially less than 100 pm and preferably less than 80 pm. The adapter 200 therefore makes it possible to regulate the size of the droplets in the aerosol suspension and to standardize this aerosol suspension at the outlet of the nozzles. Such a uniform aerosol suspension allows a homogeneous mixing of the two polyelectrolyte solutions and a conjugate interaction between the two polyelectrolytes at the outlet of the nozzles, allowing the formation of a soluble and uniform functional reaction layer, while avoiding the formation of a residual highly aggregated complex.Advantageously, the adapter 200 is made of a plastic material, compatible with medical and / or cosmetic applications and which is easy to clean and disinfect. It is thus, for example, made of medical-grade high-density polyethylene (HDPE) or medical-grade polypropylene (PP).

[0055] The spray nozzles 156, 157 used are commercially available nozzles. For example, these are nozzles fitted to nasal spray pumps marketed by Aptar under the reference APF Futuring (registered trademark). These nozzles are advantageously made of a plastic material compatible with medical and / or cosmetic applications.

[0056] In Figure 1A, the pistons 116, 117 of the two reservoirs 106, 107 are advantageously connected to each other by means of a part 120. This part 120, forming a common push button, makes it possible to offer a larger support surface for a manipulator and makes it possible to exert identical pressure on the solutions contained in the two reservoirs 106 and 107 in order to simultaneously spray these two solutions of polycation and polyanion. The two polyelectrolytes of opposite charges being sprayed simultaneously, the two suspensions at the outlet of the nozzles mix in the air by interacting in a supramolecular manner and then form a functional reaction layer which is deposited on the surface to be treated.

[0057] A window 109 may further be provided on the upper surface of the main body 101 of the device 100 to allow a handler to view the volume of solutions remaining in the reservoirs 106, 107 during spraying.

[0058] Finally, a first and a second lateral locking part 141, 142 are advantageously arranged at the rear end of the device 100, that is to say at the end opposite the spray nozzles, and on either side of the pistons 116, 117. These parts 141, 142 are held in place between the rear end of the main body 101 and the bearing surface 120 forming a push button, by means of notches 144, 146, so that they are positioned in the extension of the main body 101 and along the pistons 116, 117 and allow the pistons 116, 117 to be locked and make it impossible to actuate them until they are removed. Any leakage of solution due to involuntary pressure on the pistons is then avoided as long as the locking parts 141, 142 are not removed from their housing. These locking parts therefore offer a guarantee of first use of the device 100.They are made from an inexpensive material, such as cardboard for example.

[0059] According to an optional variant, and as illustrated in Figure 1A, the device may further comprise a third reservoir 108, capable of containing a third solution which is intended to flow towards a third spray nozzle 158 under the action of a pressure exerted on the solution, such as the action of a mechanical pressure exerted by a third piston 118 in the example of Figure 1A. An adapter 200 is also provided between the reservoir 108 and the spray nozzle 158. The third reservoir 108 may then be fixed in the main body 101, below or above the first two reservoirs 106, 107, and in orifices formed by notches 105 provided in the lateral stiffeners 103 arranged opposite each other, on the internal lateral walls of the main body. In this case, the third solution can be, for example, a surface cleaning solution or a solution containing active agents.In the case where this third solution is a cleaning solution, it is then intended to be sprayed prior to spraying the functional coating. Such a third reservoir containing a cleaning solution is necessary when the surface, on which the deposition of the functional coating is to be carried out, has been contaminated for example. The cleaning solution can for example be physiological serum or Ringer's solution. In the case where this third solution is a solution containing active agents, it is then intended to be sprayed after spraying the functional coating in order to incorporate the active agents. The active agents can for example be cytokines, such as Interleukin-type cytokines such as Interleukin-4 for example, playing an anti-inflammatory and / or vascularization role.Whatever this third solution, in order to be able to spray it, a second support surface, forming a second push button 130, is arranged at the end of the third piston 118. Thus, the flow of the liquid contained in the third reservoir towards the third nozzle is actuated by pressure exerted by the second push button 130, independent of the first push button 120.

[0060] The device which has just been described with reference to Figures 1A and 1B applies more particularly to the spraying of antimicrobial coatings on living or non-living surfaces. For such an application, and for reasons of hygiene, this device is intended for single use and must be discarded after use. In this case, the locking parts 141, 142 not only prevent accidental flow of the solutions but also ensure that the device has not been previously used. Alternatively, in the case where this device is used for a non-medical application, not requiring extensive cleaning and disinfection, then it can be reused.

[0061] Figure 3 shows an exploded perspective diagram of a skin coating applicator and Figure 4 shows an exploded perspective diagram of a functional hair coating spray device. The same references are used in both figures to designate the same elements. These devices may be intended for professionals such as nurses or doctors for the skin applicator in order to apply an antimicrobial coating to a wound for example, or for hairdressers for the hair spray device. They may also be intended for the general public. These devices are in the form of a housing 300, of substantially rectangular shape, and comprise two reservoirs 306, 307 respectively containing a polycation solution and a polyanion solution, each reservoir being connected to a spray nozzle 356, 357 via an adapter 200 as described previously.Pistons 316, 317, when actuated by a manipulator, allow mechanical pressure to be exerted on the solutions contained in the reservoirs 306, 307 and cause them to flow towards their respective spray nozzle. The pistons protrude from the housing 300 through an opening opposite the nozzles. A push button 320 covers the pistons and allows a manipulator to exert simultaneous pressure on the two pistons 316, 317 so that the two solutions are sprayed simultaneously. The push button 320 slides in the housing 300 as the pressure is exerted. A slightly hollowed-out ergonomic shape 310 may, for example, be provided on the surface of the housing to facilitate handling of the device.The housing, reservoirs and pistons, adapters and nozzles are preferably made of a plastic material compatible with medical or cosmetic applications such as polypropylene (PP) or medical grade high-density polyethylene (HDPE), for example.

[0062] The hair spray device, illustrated in Figure 4, differs from the skin spray device in that it further comprises, at the end of the housing 300 through which the solutions are sprayed, brushes 311. Similarly, an internal brush 312 is further attached to the spray nozzles 356, 357, by means of orifices 314 and flats 313, the shapes of which are complementary to those of the nozzles. These brushes 311 and 312, intended to come into contact with the hair, are preferably made of a flexible elastomeric plastic.

[0063] Preferably, each reservoir may be sized for a spray volume of between 0.5 and 10 milliliters. The polyelectrolyte solutions are sprayed simultaneously onto a surface arranged at a distance from the nozzles of substantially between 5 and 25 centimeters, preferably between 5 and 20 centimeters.

[0064] In general, these devices are designed for single use and are discarded after use. However, in the context of general public use not requiring extensive disinfection, such as for the application of a functional hair conditioning coating for example, it is possible to envisage reuse of such a device. In this case, the housing 300 can be opened in order to remove the empty reservoirs from their housing. The device is then cleaned and dried and new reservoirs filled with spray solutions are replaced in their housing, then the device is closed and ready to be used again.

[0065] Second electromechanical embodiment:

[0066] According to a second embodiment, as illustrated in Figure 5 which represents a very simplified diagram, the device is an electromechanical device.

[0067] Its housing 1000 advantageously comprises a motor 1120 powered by a battery 1100 and enabling an air pump 1110 to be actuated. The air pump 1110 enables air to be injected into each reservoir 1200, 1220 in order to exert sufficient pressure on the solution contained in said reservoir to cause it to flow in a flow channel associated therewith and formed between said reservoir and the outlet orifice of the associated nozzle. The air pump 1110 therefore makes it possible to inject air 1113 into each reservoir by means of a first and a second air flow pipe 1111, 1112 connecting the pump 1110 to each reservoir 1200, 1220. Such air flow pipes 1111, 1112 are preferably made of a flexible material preferably chosen from elastomers such as silicones for example.

[0068] Preferably, each reservoir 1200, 1220 is sized for a spray volume substantially between 0.5 and 10 milliliters. The reservoirs may be either removable or integrated into the device, depending on the intended use. When the reservoirs are removable, they are easy to clean, refill, and replace if damaged, but attaching them to the device requires the use of a leak-proof seal to prevent any risk of leakage. The integrated reservoirs are sealed to the device, they each include a valve capable of being opened or closed and through the opening of which the reservoir can be refilled, but they are difficult to clean and present a risk of spilling the solution.

[0069] Injecting air 1113 into each reservoir 1200, 1220 exerts pressure on the solution contained in each reservoir, and then causes said solution to flow into a tube 1210, 1230 placed in the reservoir, towards its spray nozzle 1510, 1520 via a flow pipe 1211, 1231. The flow pipe 1211, 1231 is advantageously made of a very flexible plastic material, compatible with medical and / or cosmetic applications. This material may preferably be chosen from elastomers such as silicones, polydimethylsiloxane (PDMS), polyurethane (PU) or low density polyethylene (LDPE) for example.

[0070] According to a first variant, each nozzle advantageously comprises two inlet orifices. A first orifice is connected to the solution flow pipe 1211, 1231. A second orifice is connected to a third air flow pipe 1114 connected directly to the air pump 1110. Injecting air also directly into each spray nozzle, as close as possible to its outlet orifice, makes it possible to promote the creation of a misty suspension of polyelectrolytes.

[0071] Figure 6 shows a sectional view of a spray nozzle 1510 according to this first variant, used for this second embodiment of the device. The outer periphery 1516 of the two inlet orifices is striated in order to allow the insertion and holding in position of the flow pipes 1211, 1114 respectively of the polyelectrolyte solution and the air. Advantageously, the orifice on which the flow pipe 1211, 1231 of the polyelectrolyte solution is intended to be fixed, is extended by a first conduit 1511, 1512, forming a conical section of the flow channel of the solution, so that the diameter of the flow channel, formed from the outlet orifice of the tube 1210 of the reservoir 1200 passing through the flow pipe 1211, to the outlet orifice 1515 of the nozzle 1510 is reduced by a predetermined factor F.This predetermined factor can advantageously be between 2 and 16, and preferably between 4 and 8 for the envisaged applications. Such a reduction in the diameter of the flow channel of the solution to be sprayed, combined with the pressure exerted on said solution, makes it possible to force the liquid to fragment into fine droplets to obtain, at the outlet 1515 of the spray nozzle 1510, droplets whose diameter is substantially less than 100 pm and preferably less than 80 pm. Preferably, the conduit 1511, 1512 opens into a mixing chamber 1514 located upstream of the outlet orifice 1515 of the nozzle. The second inlet orifice, on which the third air flow pipe 1114 is intended to be fixed, is extended by a second conduit 1513 of constant diameter until it opens into the mixing chamber 1514 located upstream of the outlet orifice 1515.This mixing chamber 1514 advantageously allows the fine droplets of the polyelectrolyte solution to be mixed with pressurized air just before they are sprayed through the outlet orifice 1515 of the nozzle. Mixing the solution, broken into fine droplets, with pressurized air promotes the production, at the nozzle outlet, of a uniform and homogeneous aerosol suspension. The closer the liquid and air mix to the outlet orifice 1515 of the nozzle, the better the homogeneity of the suspension will be. Advantageously, this mixing takes place in the mixing chamber 1514, located at a distance substantially less than or equal to 2.5 millimeters from the outlet orifice 1515 of the nozzle, preferably at a distance of the order of 2 millimeters. The two aerosol suspensions of inversely charged polyelectrolytes being uniform and homogeneous, their reaction by supramolecular interaction at the nozzle outlet is favored.The reaction layer obtained is then deposited on the surface to be covered.

[0072] According to a second variant, not shown, each nozzle comprises a single inlet orifice connected to the flow pipe 1211, 1231 of the solution. In this case, the air is only injected into each reservoir to exert pressure on the solution and cause the flow of each solution. According to this second variant, the inlet orifice of the nozzle, on which the flow pipe 1211, 1231 of the polyelectrolyte solution is intended to be fixed, is also extended by a conduit forming a conical section of the flow channel of the solution. Thus, the flow channel, formed from the outlet orifice of the tube 1210, 1230 of a reservoir 1200, 1220 via the flow pipe 1211, 1231, to the outlet orifice of the nozzle 1510, 1520 is reduced by a factor F strictly greater than one and chosen so as to cause fragmentation of the solution under pressure into droplets.Preferably, the pressure of the air injected by the air pump 1110 is between 0.8 bars and 2 bars. Such pressure is sufficient to obtain effective spraying of a functional coating on a surface to be treated, such as a wound on a person's body for example, without causing pain to the person.

[0073] The device further comprises a pressure sensor, referenced P in the diagram of figure 5, intended to measure the pressure of air injected by the air pump 1110. This pressure sensor P sends the measured pressure value to a microprocessor, not shown diagrammatically and arranged on a printed circuit board 1130. The microprocessor acts on a pressure limiting valve, not shown diagrammatically and arranged at the outlet of the air pump, so that the pressure of the air injected by the pump is adjusted to a pre-recorded set value in a memory accessible by the microprocessor or, in any case, approaches this set value with an accuracy of plus or minus 0.2 bars for example.

[0074] Flow meters, referenced D1 and D2 in the diagram of Figure 5, are further provided to measure the flow rate of each of the polycation and polyanion solutions flowing in their respective flow pipe 1211, 1231 towards their respective spray nozzle 1510, 1520. Each flow meter then sends the measured flow rate value to a microprocessor which may be identical or different from that which has just been described with regard to the pressure sensor. Depending on the measured flow rate value and the setpoint value pre-recorded in a memory accessible by the microprocessor, the latter sends an order to a selector 1140 capable of adjusting the flow rate of each of the polycation and polyanion solutions respectively to their pre-recorded setpoint values.

[0075] The selector capable of adjusting the flow rate of each of the solutions can take different forms. According to a first variant, this selector is in the form of a set of valves 1140, of the stopcock type for example, arranged in the flow channel of each solution and the opening or closing of which can be controlled manually, by operating a wheel for example, or by the microprocessor to adjust the flow rate value to the pre-recorded setpoint value.

[0076] According to another variant, the selector is in the form of a switch, capable of pinching more or less one and / or the other of the flow pipes 1211, 1231 of the polyelectrolyte solutions and thus blocking more or less the flow of the solutions. This switch 1160 will be described in more detail in the remainder of this description with reference to figures 7 and 9.

[0077] Such control of the pressure and spray flow rate of each of the polyelectrolyte solutions makes it possible to gain in precision, in the thickness and homogeneity of the coating layers deposited on a surface, compared to the first mechanical embodiment.

[0078] Figure 7 represents a semi-exploded perspective view of the device according to this second embodiment and Figure 8 a partial sectional view of this device allowing better visualization of the flow pipes of the polyelectrolyte solutions and the air flow pipes. The same references are used to designate the same elements in Figures 7 and 8. The path of the air in the air flow pipes 1111, 1113, 1114 is represented by hatched lines in Figure 8, while the path of a polyelectrolyte solution in the tube 1210 and the flow pipe 1211 is represented by small dots. The device 1000 comprises a first block 1150 comprising the motor, the battery, the air pump and the printed circuit board on which the elements of the electronic circuit are arranged such as the microprocessor(s) and the memory(s) in particular.This part may also include a touch screen, arranged for example on the upper surface of the block, in the case where a human-machine interface is added, in order to allow a manipulator to configure the set values ​​of the air pressure and the flow rate of the polycation and polyanion solutions to be sprayed. The orifice 1111 of a flow pipe opens from this block to allow the air injected by the air pump to be conveyed to the next block 1151. The air flow pipe then separates into two parts to be able to inject the air on the one hand into each reservoir 1200, 1220 (pipes referenced 1113) and on the other hand into each spray nozzle 1510, 1520 (pipes referenced 1114).

[0079] A trigger 1300 is attached to the handle 1320 by means of a rod 1310. The trigger is used to operate the motor which itself drives the air pump. During use, the air pump continuously sends air into the reservoirs 1200, 1220 and increases the pressure in each reservoir. The high pressure inside the reservoirs forces the solutions, respectively of polycation contained in the reservoir 1200 and of polyanion contained in the reservoir 1220, to flow through their respective pipes 1210, 1211; 1230, 1231 until spraying by their respective spray nozzle 1510, 1520.

[0080] The following block 1152 advantageously comprises the selector 1160. Preferably, this selector is in the form of a switch. It can be actuated manually or on command from the microprocessor to adjust the flow rate values ​​of the two polyelectrolyte solutions to pre-recorded setpoint values. The selector 1160, as shown in Figure 7 and described in more detail in Figure 9, is in the form of a switch comprising a plate 1161 surmounted by a trapezoidal button 1162 whose sides, intended to be in contact with the flexible flow pipes 1211, 1231, are rounded and flared. It is arranged in a housing 1165. The plate 1161 slides between two end positions.When the button 1162 moves from one position to another, it pinches more or less one of the flexible flow pipes 1211, 1231, making it possible to block more or less the flow of one or other of the polyelectrolyte solutions and thus to adjust its flow rate to a pre-recorded set value. Figure 9 shows a sectional view of the block 1152 including the selector 1160. Figures 9A, 9B and 9C show the selector 1160 in three different positions. The hatched circles referenced 1114 represent the air flow pipes towards the spray nozzles. References 1211 and 1231 designate the flexible flow pipes respectively for the polycation solution and the polyanion solution. The selector plate 1161 slides between a first end position referenced A, a middle position referenced B and a second end position referenced C.In the middle position B, the selector button 1162 is positioned between the flexible pipes 1211, 1231. The pipes are not pinched by the button, or are pinched very lightly, and the solutions can flow towards their respective nozzles. In position A, the button 1162 pinches the flexible pipe 1211. Under the effect of the pinching, the flow of the polycation solution is blocked. Similarly, in the end position C, the button 1162 strongly pinches the flexible pipe 1231 and blocks the flow of the polyanion solution. Between these end positions, the button can take different positions to block more or less the flow of one or other of the solutions and thus adjust the flow rate of each of the solutions to pre-recorded set values ​​in a memory, for example.In order to be able to correctly pinch the flow pipes 1211 and 1231 of the polyelectrolyte solutions, these must be made of a very flexible material chosen from elastomers for example, such as silicone or medical grade polydimethylsiloxane (PDMS) or medical grade polyurethane (PU) or even low density polyethylene (LDPE) for example.

[0081] One of the inlet orifices of each nozzle 1510, 1520 is connected to the air flow pipe 1114 while the other inlet orifice is connected to the flow pipe 1211, 1231 of one of the polyelectrolyte solutions as previously described with reference to FIG. 6. The closer the liquid and air mix to the outlet orifice of the nozzle, the better the homogeneity of the suspension will be. Advantageously, this mixing takes place in the mixing chamber 1514, located at a distance substantially less than 2.5 millimeters from the outlet orifice 1515 of the nozzle and preferably at a distance of the order of 2 millimeters. A cover 1550 covers and protects the spray nozzles 1510, 1520.

[0082] Finally, optionally, as illustrated in Figures 7 and 8, a non-return valve 1205, 1225 may be provided in each tube 1210, 1230 of each reservoir 1200, 1220, in order to prevent the solution from returning to its reservoir. Thus, even after releasing the trigger 1300, the spraying of the liquid contained in the tube 1210, 1230 is initiated and instantaneous. According to an alternative embodiment, not shown in Figures 5 to 8, the device comprises a third reservoir intended to contain a third solution. As for the first two reservoirs, pressurized air from the air pump is also injected into this third reservoir in order to cause the flow of the third solution towards a third spray nozzle dedicated to it.According to this embodiment variant, the device then comprises a second trigger specifically designed to spray only this third solution, before or after spraying the polyelectrolyte solutions. In this case, the second trigger actuates on the one hand the motor which drives the air pump and on the other hand a valve allowing the injected air to be conveyed only into the third reservoir. This third solution may be a surface cleaning solution or a solution containing active agents, as already described with regard to the first embodiment.

[0083] The pressure and flow rate setpoints for the various solutions are factory-set according to the intended use of the device.

[0084] In an alternative embodiment, it is possible to provide a human / machine interface, not shown, for example in the form of a touch screen connected to a third microprocessor, which may be identical to or different from one or both of the microprocessors previously described, and to a RAM type memory for example, to allow a manipulator to configure the pressure and flow rate setpoint values ​​of each of the solutions himself according to the application for which he wishes to use the device. Such an interface makes it possible to dose the quantities of each polyelectrolyte and to control the dosages according to the concentrations of the polyelectrolyte solutions used. It also makes it possible to configure spraying sequences for example.

[0085] Such an electromechanical device comprising a motor, an air pump, a battery, a microprocessor, one or more memories, pressure and flow sensors, has a high cost price compared to a mechanical device and it is interesting to be able to reuse it. In addition, such reuse also makes it possible to reduce the use of plastic material and therefore the ecological footprint. However, to be able to reuse it, it is necessary to be able to clean, disinfect and sterilize it correctly, for example in an autoclave then wiping with 70% ethanol, particularly for medical applications. However, the elements of the electronic circuit cannot undergo such treatment unless they are damaged.To this end, the constituent elements of the electronic circuit, including the motor, the battery, the air pump, the microprocessor(s), the memory(ies) and the possible human / machine interface, are assembled in a single closed block 1150, which is arranged in a removable housing. This removable housing can be attached to the rest of the device by clipping for example. In an alternative embodiment, this housing can be placed in a removable manner in a hollow housing provided inside the device and closed by a flap for example. The flap can thus be opened or closed to be able to slide the housing containing the electronic block, so as to remove it from or replace it in the device.

[0086] The dotted line in the diagram of Figure 5 represents a line along which the device can be disassembled into two parts, the rear part comprising the handle and the electronic elements 1100, 1110, 1120, 1130 being detached from the front part comprising the reservoirs 1200, 1220, flow pipes 1211, 1231 and nozzles 1510, 1520. The fact that the device can be disassembled in this way allows it to be reused. The front part can thus be cleaned, disinfected and sterilized before reuse, while the rear part comprising the electronic elements is kept separate and protected from cleaning, disinfection and sterilization operations.

[0087] The invention further relates to a method for spraying a functional coating of polyelectrolytes onto a surface, using the device according to one of the embodiments just described. This method consists in a first step of targeting the surface to be sprayed. This surface is made of a material chosen from living surfaces, for example skin or hair or non-living surfaces, for example glass, titanium, silicone, ceramic, or wood. The spraying device is maintained at a predetermined distance d from the surface to be sprayed. This distance d between the nozzles of the spraying device and the surface is preferably between 5 and 25 centimeters, and advantageously between 5 and 15 centimeters. The polyelectrolyte solutions are then sprayed simultaneously onto the surface, by actuating the first push button 120, 320 or the first trigger 1300.Preferably, the spraying is carried out continuously on several layers. The number n of layers is preferably between 1 and 24. For example, the polycation can be chosen from poly-L-arginine (PAR), poly-L-lysine (PLL), poly-epsilon-lysine (EPLL) or poly-L-ornithine (PLO) and the polyanion can be chosen from hyaluronic acid, alpha, lambda or kappa carrageenan, alginate or one of their derivatives.

[0088] A step prior to the simultaneous spraying of the polyelectrolyte solutions may further consist of spraying a cleaning solution onto the surface by actuating the second push button 130 or the second trigger in order to prepare the surface and decontaminate it before applying the functional coating.

[0089] According to another variant, a step subsequent to the simultaneous spraying of the polyelectrolyte solutions may further consist of spraying a solution containing active agents, by actuating the second push button 130 or the second trigger, in order to incorporate these active agents into the functional coating.

[0090] Examples:

[0091] For illustrative purposes, examples of coatings made on different surfaces are described below. These examples do not limit the scope of the invention in any way.

[0092] Antimicrobial multilayer coatings were sprayed onto different substrates with different polyelectrolytes. Poly-L-arginine (PAR) polycations are marketed by Alamanda Polymers, USA. For the tests carried out, the PAR30 molecule, comprising 30 monomer units, Mw=6.4kDa, PD I = 1.01, was used. E-Poly-L-lysine EPLL is marketed by Biosynth, UK. The chosen polyanion is Hyaluronic acid (HA, Mw=150kDa), and more specifically HA144, comprising 144 monomer units, marketed by Lifecore Biomed, USA.

[0093] The polycation PAR 30 or EPLL and the polyanion HA144 were respectively dissolved at different concentrations in a sterile buffer solution containing 150 mM NaCl and 10 mM tris(hydroxymethyl)-aminomethane (TRIS) with the pH adjusted to 7.4.

[0094] Different compositions of functional coatings were studied on different types of substrates. Their effectiveness against certain bacteria such as Staphylococcus aureus strains (S. aureus, ATCC 25923), Escherichia Coli strains (E. coli, ATCC 25922) and Pseudomonas Aeruginosa strains (P. aeruginosa, ATCC 27853) was then studied.

[0095] Example 1: production of functional coatings by spraying:

[0096] Coatings were made by simultaneously spraying polycation and polyanion solutions onto the surface of various glass, titanium, or silicone substrates. The experiments were carried out by placing the spray nozzles at a distance d from the substrate surface of 10, 15, or 20 centimeters.

[0097] After waiting for about 15 minutes after spraying, the resulting coatings were observed using a confocal laser scanning microscope with an argon ion laser. For this purpose, the coatings were labeled with a surface layer of fluorescein isothiocyanate (FITC). The coating then exhibits a green color under the argon ion laser scan. The ZEN microscopy software for the exploitation of the observed images was then used. The cross-sectional images of coatings representing thick bands with a green marking across the entire coating indicate that the coatings were deposited homogeneously over the entire surface.

[0098] The observed results showed the importance of the spray pattern and the polyelectrolyte concentration. It turned out that a single layer sprayed on the surface of a substrate is not enough to observe a coating since no bands with a green marking are observed. On the other hand, coating deposits are observed when the latter is carried out in several sprays, preferably at least 3 sprays, continuously and in a back and forth movement.

[0099] Figure 10 shows cross-sectional images of different coating compositions obtained by spraying polyelectrolyte solutions in accordance with the invention. For all compositions, sprayed in three layers at a distance of 10, 15 or 20 centimeters from the substrate, and regardless of the substrate chosen from glass, medical grade titanium or medical grade silicone, the presence of a homogeneously deposited coating is observed.

[0100] Example 2: Antibacterial analysis:

[0101] The antimicrobial properties of different coatings sprayed at different distances d onto different substrates selected from glass, titanium and silicone were evaluated.

[0102] The films were tested against the gram-positive bacterium S. aureus, a well-known strain associated with nosocomial infections and more particularly in cases of implant-related infections.

[0103] The bacterial strains were grown aerobically at 37°C in Mueller Hinton Broth (MHB) medium (Merck, Germany), at a pH of 7.4. One colony was transferred to 10 milliliters of MHB medium and incubated at 37°C for 20 hours, to provide a final colony-forming unit (CFU) density of 106 CFU.ml-1. A spectrophotometer was used to measure the optical density OD (or Absorbance A) at 620 nanometers. If the bacteria are dead, the medium will be transparent and therefore have a low OD (or A) value. To obtain bacteria in the mid-log phase of growth, the absorbance at 620 nanometers of the overnight culture was adjusted to A620 = 0.001.

[0104] The surface of the glass substrates used was sterilized using UV light for 15 minutes and then washed with a NaCl-Tris buffer solution. After washing, each glass substrate was subjected to spraying with a multilayer functional coating of a given composition, said spraying being carried out continuously for a number of back and forths between 6 and 13. The substrate was then deposited in 24-well plates with 300 μl of S. aureus, A620 = 0.001 and incubated for 24 hours at 37°C. The normalized growth of pathogens (in %) was estimated by comparing the absorbance A at 620 nanometers in the presence of multilayer coating with the absorbance of positive control (without multilayer coating and with antibiotics in the medium) and with the absorbance of negative control (without multilayer coating and in the absence of antibiotics in the medium).

[0105] For negative control, uncoated glass substrates were directly incubated with S. aureus using a similar method. For positive control, antibiotics selected from tetracycline (10 pg.ml-1 ) and cefotaxime (0.1 pg.ml-1 ) were added into the S. aureus solution in contact with uncoated glass substrates. For sample control, an uncoated glass substrate was immersed in colony-free MBH medium.

[0106] To quantify bacterial growth or inhibition after 24 hours, the absorbance A of the supernatant at 620 nanometers was measured spectrophotometrically.

[0107] The various multi-layer coatings were then tested on other Gram-positive and Gram-negative bacteria. They were tested against strains of Pseudomonas Aeruginosa (P. aeruginosa, ATCC 27853) and strains of Escherichia Coli (E. coli, ATCC 25922). The antibacterial test for E. coli and P. aeruginosa was performed in the same manner as the antibacterial test for S. aureus as described above. The test was performed in the same manner for titanium and silicone substrates.

[0108] The graphs in Figures 11 A, 11 B and 11C demonstrate the inhibition of S. aureus growth using the same composition of 10 mg / ml PAR30 and 5 mg / ml HA144 in a 0.02 M Tris-NaCl buffer solution, pH 7.4, spray-coated onto glass (Figure 11 A), silicone (Figure 11 B) and titanium (Figure 11C) substrates. Each experiment was conducted on three samples E, F, G. Error bars correspond to standard deviations. The coating was deposited in twelve sprays in a back and forth pattern on each substrate, at a distance d of 10 and 15 centimeters. It appears in Figure 11A that the coating deposited on a glass substrate at 10 and 15 centimeters shows an average growth of S. aureus of less than 5%. The coating deposited on a medical grade silicone substrate at 10 and 15 centimeters shows an average growth of S. aureus of less than 3% (Figure 11 B).The coating deposited on a medical grade titanium substrate at 10 and 15 centimeters shows an average growth of S. aureus of less than 5% (Figure 11C). These results therefore demonstrate a strong inhibition of the growth of S. aureus regardless of the substrate.

[0109] The graphs in Figures 12A to 12D demonstrate the growth inhibition of P. aeruginosa, E. coli, and S. aureus bacteria using a composition of 10 mg / ml EPLL and 1 mg / ml HA144 in a 0.02 M Tris-NaCl buffer solution, pH 7.4, spray-coated onto silicone or glass substrates. The composition of 10 mg / ml EPLL and 1 mg / ml HA144 was spray-coated in ten layers onto a medical-grade silicone substrate. The samples were tested against P. aeruginosa (Figure 12A), E. coli (Figure 12B), and S. aureus (Figure 12C). This same composition was coated onto a glass substrate in six layers and tested against P. aeruginosa (Figure 12D). The graph in Figure 12A represents the growth inhibition of P. aeruginosa on a medical grade silicone substrate for which the average growth of P.aeruginosa is less than 5% when the coating is sprayed from a distance of 10 centimeters and less than 3% when the coating is sprayed from a distance of 15 centimeters. Each experiment was conducted on three samples A, B and C. Error bars correspond to standard deviations.

[0110] The graph in Figure 12B represents the growth inhibition of E. coli on a medical-grade silicone substrate, for which the average growth of E. coli is less than 3% when the coating is sprayed from a distance of 10 centimeters and from a distance of 15 centimeters. Each experiment was conducted on three samples E, F, and G. Error bars correspond to standard deviations.

[0111] The graph in Figure 12C represents the growth inhibition of S. aureus on a medical-grade silicone substrate, for which the average growth of S. aureus is less than 1% when the coating is sprayed from a distance of 10 centimeters and from a distance of 15 centimeters. Each experiment was conducted on three samples A, B, and C. Error bars correspond to standard deviations.

[0112] The graph in Figure 12D represents the growth inhibition of P. aeruginosa using this composition of 10 mg / ml of EPLL and 1 mg / ml of HA144 in a 0.02 M Tris-NaCl buffer solution, pH 7.4, spray-coated in six layers on a glass substrate. Each experiment was conducted on three samples A, B and C. The error bars correspond to the standard deviations. It appears from Figure 12D that the coating of the composition of 10 mg / ml of EPLL and 1 mg / ml of HA144 sprayed in six layers on a glass substrate at a distance d of 15 and 20 centimeters exhibits an average growth of P. aeruginosa of less than 1%.

[0113] All the results of experiments conducted with different compositions of polyelectrolytes, sprayed in a multi-layer coating on different substrates, at a distance of between 10 and 20 centimeters, demonstrate a strong inhibition of the growth of the bacteria S. aureus, P. aeruginosa and E. Coli.

[0114] Tests were also conducted to determine the antibacterial efficacy against S. aureus and P. aeruginosa of a spray of a composition of 10 mg / ml of PAR30 and 5 mg / ml of HA144 in a 0.02 M Tris-NaCl buffer solution, pH 7.4, depending on the spraying distance, the surface area covered and the number of sprayed layers. When the composition is sprayed, a dilution takes place and the final concentration on a wound is 5 mg / ml of PAR30 and 2.5 mg / ml of HA144. The tests carried out showed that good antimicrobial efficacy could be obtained for a spraying distance of 10 centimeters, by spraying at least five layers of the composition. Such a spray allows coverage of an area of ​​300 cm 2 .

[0115] Further studies have been conducted with other polyelectrolyte compositions on different surfaces and the results obtained demonstrate the effectiveness of the antibacterial activity of the coatings obtained by spraying against different bacteria.

[0116] Example 3: In vivo tests of antibacterial efficacy, cytotoxicity and in vivo behavior of a sprayed functional coating:

[0117] Antibacterial tests were conducted on mice that were divided into two groups. Mice in both groups underwent two surgical incisions. Five minutes after the incision, S aureus bacteria were injected into the incision and then a first group of mice underwent spray treatment with a composition of 10 mg / ml of PAR30 and 5 mg / ml of HA144 in a 0.02 M Tris-NaCl buffer solution, pH 7.4, while the second control group was treated by applying a sterile adhesive bandage, such as a bandage marketed by 3M under the trademark “Tegaderm”. The growth of S aureus on the skin of the mice as well as on the sterile bandage and on the functional coating was analyzed by bioluminescence after 24 hours and 48 hours. Figure 13A represents the growth of S. aureus bacteria obtained by bioluminescence imaging as a function of time.The results showed a significant reduction in S aureus bacteria in wounds treated with spray compared to wounds treated with sterile dressing and thus proved the effectiveness of the spray device for antibacterial applications.

[0118] Cytotoxicity tests were then conducted on mice, which were divided into three groups. A first group of mice received nothing and constituted the control group. A second group of mice underwent two surgical incisions and was not treated. A third group of mice underwent two surgical incisions and the wounds were treated by spraying with a composition of 10 mg / ml of PAR30 and 5 mg / ml of HA144 in a 0.02 M Tris-NaCl buffer solution, pH 7.4. In vivo inflammatory response monitoring was performed 3 hours and then 24 hours after surgical incision by fluorescence imaging. The results showed that inflammation was detected and increased after 3 hours among the injured groups, whether they were sprayed or not. This inflammation then decreased 24 hours after wound creation in all injured groups, whether they were sprayed or not.Therefore, there are no significant differences between all groups, meaning that the spray treatment did not induce a high inflammatory response.

[0119] Spray coating sensitivity tests were further conducted on mice, which were divided into four groups. A first group of mice underwent a hind paw incision followed by a spray treatment protocol with a composition of 10 mg / ml PAR30 and 5 mg / ml HA144 in a 0.02 M Tris-NaCl buffer solution, pH 7.4. A second group of mice underwent a hind paw incision followed by a spray treatment protocol with a 0.9% NaCl saline solution. A third group of mice underwent no incision and underwent a spray treatment protocol with a composition of 10 mg / ml PAR30 and 5 mg / ml HA144 in a 0.02 M Tris-NaCl buffer solution, pH 7.4. The fourth group, control, underwent no incision and underwent a treatment protocol by spraying a saline solution of 0.9% NaCl.The spraying protocol consisted of performing a first spray on the muscle just after the incision, then performing a second spray on the skin after suturing, then a third and fourth spray on the skin respectively 2 hours and 24 hours after the second spray.

[0120] The treatment effect was assessed using a first mechanical nociceptive test called the Von Frey filament test, which measures the mechanical sensitivity threshold of mouse hindpaws with calibrated nylon filaments. Results were expressed in grams. Mice were placed in clear Plexiglas boxes on a raised metal grid. After a 15-minute habituation period, Von Frey filaments were applied to the plantar surface of each hindpaw at a series of upward forces ranging from 0.4 to 10 g. The first filament causing at least three paw withdrawals out of five successive applications determined a threshold. The test results shown in Figure 13B show that mice spray-treated with the functional coating do not exhibit mechanical hypersensitivity.

[0121] The effect of treatment application was then assessed using a nociceptive thermal test called the dry ice test. Mice were placed in transparent Plexiglas boxes on a glass surface. After a 10-minute habituation period, a syringe of dry ice (0.5 cm diameter) was placed under the plantar surface of each hind paw. This test measures paw withdrawal latencies, and three paw withdrawal latency measurements are required, and an average is calculated for each hind paw. The threshold to avoid skin damage is set at 20 seconds. The test results shown in Figure 13C show that incised mice that underwent the functional coating spray protocol exhibited cold hypersensitivity, but to a lesser extent than non-incised mice in the control groups.

[0122] The effect of the treatment application was finally evaluated using a nociceptive thermal test called the Hargreaves method. This test measures the hind paw withdrawal latency in response to thermal stimulation. The mice were placed in transparent Plexiglas boxes on a glass surface. After a 10-minute habituation period, the fiber optic heat source was placed under the plantar surface of each hind paw. This test measures paw withdrawal latencies, and three paw withdrawal latency measurements are required, and an average is calculated for each hind paw. The threshold to avoid skin damage is set at 20 seconds (the infrared beam automatically turns off after 20 seconds). The test results shown in Figure 13D show that mice sprayed with the functional coating do not exhibit any hypersensitivity to heat.

[0123] The invention just described was for polyelectrolytes. However, the invention applies to other supramolecular structures such as Pi-Pi stacking structures, FMOC (fluorenylmethoxycarbonyl) chemistry when using peptides, or structures with biological interactions for example.

Claims

CLAIMS 1. Device (100, 300, 1000) for spraying a functional coating of supramolecular structures onto a surface, comprising at least two reservoirs (106, 107; 306, 307; 1200, 1220), a first reservoir (106; 306; 1200) capable of receiving a first solution of a polycation and a second reservoir (107; 307; 1220) capable of receiving a second solution of a polyanion, at least a first (156; 356; 1510) and a second nozzle (157; 357;1520) for spraying respectively the first polycation solution and the second polyanion solution, the flow respectively of said first and second solutions in a first and a second flow channel, formed respectively between said first (106, 306, 1200) and second reservoirs (107, 307, 1220) and the outlet orifice (156B, 157B, 1515) of said first and second nozzles, being caused by a pressure exerted on said solutions in their respective reservoir, said device being characterized in that said first and second flow channels respectively have at least one section (212, 1511) of conical shape so that their diameter decreases, from said first and second reservoirs to the outlet orifice of said first and second nozzles, by a factor F strictly greater than one and chosen so as to cause a fragmentation of said first and second solutions under pressure into droplets.; 2. Device (100, 300, 1000) according to claim 1, characterized in that the factor F of reduction of the diameter of said first and second flow channels is between 2 and 16, preferably between 4 and 8.

3. Device (100, 300) according to one of claims 1 to 2, characterized in that each spray nozzle (156, 157) is connected respectively to the first (106, 306) and to the second (107, 307) reservoir by means of an adapter (200) comprising a conduit (212) forming said conical section respectively of said first and second flow channel.

4. Device (100, 300) according to one of claims 1 to 3, characterized in that the first (106, 306) and second (107, 307) reservoirs respectively comprise a first (116; 316) and a second (117; 317) pistons respectively arranged to exert mechanical pressure on said first and second solutions contained respectively in the first (106, 306) and second (107, 307) reservoirs.

5. Device (100, 300) according to claim 4, characterized in that the first (116; 316) and second (117; 317) pistons are connected to each other by a first push button (120; 320) making it possible to exert simultaneous pressure on said first polycation solution and second polyanion solution and to cause their simultaneous spraying.

6. Device (100) according to one of claims 1 to 5, characterized in that it comprises a third reservoir (108) and a third spray nozzle (158), said third reservoir being capable of receiving a third solution, said third solution flowing in a third flow channel, formed between the third reservoir (108) and the outlet orifice of the third spray nozzle (158), under the action of mechanical pressure exerted on said third solution in its reservoir by a third piston (118), and in that the device comprises a second push button (130) capable of exerting pressure on said third piston (118) to allow the flow of said third solution towards said third spray nozzle (158).

7. Device (1000) according to claim 1, characterized in that it further comprises a motor (1120) powered by a battery (1100) and making it possible to actuate an air pump (1110) intended to inject air, via at least a first and a second air flow pipe (1113), into said at least first (1200) and second (1220) reservoirs, and in that said first and second solutions flow respectively in a first (1211) and a second (1231) flow pipe towards their respective spray nozzle (1510, 1520), under the effect of the pressure exerted by the injected air.

8. Device (1000) according to claims 1 and 7, characterized in that each spray nozzle (1510; 1520) comprises two inlet orifices and one outlet orifice (1515); a first inlet orifice being connected to the flow pipe (1211, 1231) of one of said first or second solutions and extending by a first conduit (1511, 1512), forming said conical section respectively of one of said first or second flow channels and opening into a mixing chamber (1514) located upstream of the outlet orifice (1515), and a second inlet orifice being connected to a third air flow pipe (1114) and extending by a second conduit (1513) opening into said mixing chamber (1514) in which said first or second solution and pressurized air mix before being sprayed through the outlet (1515).

9. Device (1000) according to one of claims 7 to 8, characterized in that it further comprises a microprocessor capable of acting on a valve to adjust the air pressure injected by the air pump. (1110) to a pre-recorded setpoint value and a pressure sensor (P) intended to measure said pressure, said pressure sensor (P) addressing the measured pressure value to said microprocessor.

10. Device (1000) according to one of claims 7 to 8, characterized in that it further comprises at least a first (D1) and a second (D2) flow meter capable of measuring the flow rate respectively of the first polycation solution and of the second polyanion solution flowing respectively in their flow pipe (1211; 1231), towards their spray nozzle and a microprocessor capable of acting on a selector (1140, 1160) to adjust said flow rate values ​​to pre-recorded setpoint values, said measured flow rate values ​​being addressed to said microprocessor.

11. Device (1000) according to claim 10, characterized in that the first and second flow pipes (1211, 1231) of said first and second solutions are made of a flexible material and in that said selector (1160) is in the form of a switch button (1162) capable of sliding between two end positions and of pinching one and / or the other of the flow pipes (1211, 1231) of said first and / or second solutions.

12. Device according to one of claims 7 to 8, characterized in that it further comprises a microprocessor and a human-machine interface, in the form of a touch screen connected to said microprocessor and to a memory, making it possible to configure setpoint values ​​for the air pressure and the flow rate of said solutions.

13. Device (1000) according to one of claims 9 to 12, characterized in that an electronic block (1150), comprising the motor (1120), the air pump (1110), the battery (1100), the microprocessor(s), and at least one memory, is arranged in a removable housing intended to be separated from the device (1000) during cleaning, disinfection and sterilization operations.

14. Method for spraying a functional coating of supramolecular structures onto a surface, using the device according to one of claims 1 to 13, characterized in that it comprises the steps of targeting the surface to be sprayed, maintaining the device at a distance d from the surface of between 5 and 15 centimeters, and simultaneously spraying the polyelectrolyte solutions onto said surface, under a pressure of less than 2 bars, said spraying being able to be carried out continuously on several layers.

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