PHOTOBIOMODULATION DEVICE

Abstract

A light source device including a light emitting element for emitting a light having the following characteristics: a wavelength ranging from 435 to 520 nm, and a power density greater than 20 mW/cm.sup.2, the light source device provides an effective fluence to any contaminating and/or pathogenic agent greater than 11 J/cm2. Also, a light source assembly including a product adapted to be in contact with a support or a medium, preferably the skin or a wound and a light source device connected to the product for providing light to at least one contaminating and/or pathogenic agent present on a support or in a medium.

Claims

1.-16. (canceled)

17. A light source device comprising a light emitting element for emitting a light having the following characteristics: a wavelength ranging from 435 to 520 nm, and a power density greater than 20 mW/cm.sup.2, the light source device providing an effective fluence to any contaminating and/or pathogenic agent greater than 11 J/cm.sup.2.

18. The light source device according to claim 17, wherein the dominant emission wavelength ranges from 440 to 490 nm, more particularly from 450 to 460 nm.

19. The light source device according to claim 17, wherein the light source device provides an effective fluence to any contaminating and/or pathogenic agent greater than 40 J/cm.sup.2, preferably greater than 80 J/cm.sup.2.

20. The light source device according to claim 17, wherein the light emitting element has a power density ranging from 23 to 400 mW/cm.sup.2, more particularly a power density ranging from 21 to 150 mW/cm.sup.2, and more particularly from 23 to 46 mW/cm.sup.2.

21. The light source device according to claim 17, wherein the ratio between the effective fluence and the power density is greater than 1.7 preferably greater than 3.

22. The light source device according to claim 17, wherein said light emitting element comprises at least one LED.

23. The light source device according to claim 17, further comprising a power source providing electrical power to said light emitting element.

24. The light source device according to claim 23, wherein the contaminating and/or pathogenic agent is a microorganism such as bacteria, yeasts or fungi, preferably bacteria.

25. The light source device according to claim 17, wherein the contaminating and/or pathogenic agent is a bacteria, in particular a Gram-positive or Gram-negative bacteria, preferably chosen from S. aureus and P. aeruginosa.

26. A light source assembly comprising: a product adapted to be in contact with a support, in particular a surface, including the skin, mucosa or a wound; a light source device according to claim 17 connected to the product to provide light to at least one contaminating and/or pathogenic agent.

27. The light source assembly according to claim 26, wherein the product is one among a dressing, a strip, a compression means, a band-aid, a patch, a gel, a film-forming composition and a rigid or flexible support, preferably a dressing.

28.-32. (canceled)

33. A method for inhibiting growth and reducing number of contaminating and/or pathogenic agent, the method comprising the step of: exposing the at least one contaminating and/or pathogenic agent with a light source device comprising a light emitting element for emitting a blue light having a wavelength ranging from 425 to 500 nm, the light source device being configured to provide an effective fluence to said contaminating and/or pathogenic agent greater than 11 J/cm.sup.2, and a power density greater than 20 mW/cm.sup.2.

34. The method of claim 33, wherein the emission wavelength of the light emitting element ranges from 440 to 490 nm, more particularly from 450 to 460 nm.

35. The method of claim 33, wherein the light source device is configured to provide blue light at an effective fluence to any contaminating and/or pathogenic agent greater than 40 J/cm.sup.2, preferably greater than 80 J/cm.sup.2.

36. The method of claim 33, wherein the light emitting element is configured to provide a power density ranging from 23 to 400 mW/cm.sup.2, more particularly a power density ranging from 21 to 150 mW/cm.sup.2, and more particularly from 23 to 46 mW/cm.sup.2.

37. The method of claim 33, wherein the ratio between the effective fluence and the power density is greater than 1.7 preferably greater than 3.

38. The method according to claim 33, wherein the contaminating and/or pathogenic agent is a microorganism such as bacteria, yeasts or fungi, preferably bacteria.

39. The method according to claim 33, wherein the contaminating and/or pathogenic agent is a bacteria, in particular a Gram-positive or Gram-negative bacteria, preferably chosen from S. aureus and P. aeruginosa.

40. A method for reducing the contaminating and/or pathogenic agent's growth and number, comprising exposing a contaminating and/or pathogenic agent to the light source device according to claim 17 or a light source assembly comprising a product adapted to be in contact with a support, in particular a surface, including the skin, mucosa or a wound, and said light source device connected to the product to provide light to at least one contaminating and/or pathogenic agent.

41. The method according to claim 40, wherein reducing the contaminating and/or pathogenic agent's growth and number is for the treatment of medium, or surface decontamination, preferably through a photobiomodulation means.

42. The method according to claim 40, wherein reducing the contaminating and/or pathogenic agent's growth and number is for the disinfection of wounds, mucosa, and skin, preferably through a photobiomodulation means.

43. The method according to claim 40, wherein reducing the contaminating and/or pathogenic agent's growth and number is for the decontamination or disinfection of packing, wrapping, food products, and cleaning and/or domestic devices, preferably through a photobiomodulation means.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] FIG. 1 represents in a cross section view an embodiment of a photobiomodulation device used in the treatment of various supports or medium for promoting the growth and number reduction of contaminating and/or pathogenic agents in vitro or in vivo.

[0036] FIG. 2 represents a histogram comparing the effect on colony count of E. coli in blue light irradiation conditions (453 nm, defined as BLI) vs without irradiation (defined as control), and for irradicance values of 23 mW/cm.sup.2.

[0037] FIG. 3 represents a histogram comparing the effect on colony count of E. coli in blue light irradiation conditions (453 nm, defined as BLI) Vs without irradiation (defined as control), and for irradicance values of 10 mW/cm.sup.2.

[0038] FIG. 4 represents two curves comparing the effect on colony count of K. pneumoniae in continuous blue light irradiation conditions (453 nm) vs discontinuous blue light irradiation conditions (453 nm, light exposure ratio of 50%, frequency of 0.02 Hertz) and for irradiance values of 23 mW/cm.sup.2.

[0039] FIG. 5 represents two curves comparing the effect on colony count of P. aeruginosa in continuous blue light irradiation conditions (453 nm) vs discontinuous blue light irradiation conditions (453 nm, light exposure ratio of 50%, frequency of 0.02 Hertz) and for irradiance values of 23 mW/cm.sup.2.

[0040] FIG. 6 represents two curves comparing the effect on colony count of E. coli in continuous blue light irradiation conditions (453 nm) vs discontinuous blue light irradiation conditions (453 nm, light exposure ratio of 50%, frequency of 0.02 Hertz) and for irradiance values of 23 mW/cm.sup.2.

DETAILED DESCRIPTION

[0041] The present invention will be described below relative to several specific embodiments. Those skilled in the art will appreciate that the present invention may be implemented in a number of different applications and embodiments and is not specifically limited in its application to the particular embodiment depicted herein.

[0042] For the purpose of the present invention, the following terms are defined.

[0043] The term Wavelength is the distance between two peaks of a wave. The symbol for wavelength is (lambda) and the unit of measurement is nanometers (nm).

[0044] The term Dominant emission wavelength is the wavelength or a narrow range of wavelengths the light source emits the majority of the time. The term power refers to the rate at which work is perform; the unit of power is Watt (W) and since the light output power is low it is expressed in milliwatts (mW).

[0045] The term power density or light intensity, or irradiance, or exitance is the power divided by the area of the target being illuminated by the light and is expressed in mW/cm.sup.2.

[0046] The term fluence or energy density or dose expressed in Joules per cm.sup.2 (J/cm.sup.2) is the product of power (mW) and time per spot size (cm.sup.2).

[0047] The term transmitted fluence is the fluence produced by the claimed light source, whereas the term effective fluence is the fluence actually received by the contaminating and/or pathogenic agent. Indeed, as will be further explained below, the effective fluence may be lower than the transmitted fluence depending, in particular, on the environment (medium or support) of the agent.

[0048] The term photobiomodulation is the ability of the light source device to have a biological effect on cells, or on contaminating and/or pathogenic agents, directly, which means without the need of any provisional product or composition to transpose or potentialize any biological effect engendered by the light source. This term can be distinguished from the term of photodynamic therapy which needs absolutely and every time the intervention of an intermediate product between the light source and the cells or contaminating and/or pathogenic agent to potentialize the biological effect of the light.

[0049] The term contaminating and/or pathogenic agent is intended to designate any microorganism such as bacteria, yeast or fungi, any virus or any organisms in contact with a skin, wound or mucosa such as parasite, louse, dust mite or worm.

[0050] By contaminating agent, we intend to qualify any one of the contaminating and/or pathogenic agent listed above able to grow and proliferate on a specific support or in a specific medium (including an inert surface, a pharmaceutical composition, a biological surface, more particularly a skin, a mucosa or a wound, or any eventual food product, drink or beverage).

[0051] By pathogenic agent, we intend to qualify any contaminating agent capable of inducing a disease or a biological trouble to an animal or a human being.

[0052] The term support is intended to designate any substrate or surface on which a contaminating and/or pathogenic agent can grow and proliferate, including an inert surface, a biological surface more particularly a skin, a mucosa, a wound, or any eventual food product or packing.

[0053] The term medium is intended to designate any environment in which bacteria can develop, grow and proliferate, including a pharmaceuticals composition, used waters, liquids, or the air.

[0054] The term microorganism is intended to designate bacteria, yeasts, and fungi.

[0055] The expression growth and number reduction of contaminating and/or pathogenic agent means that microorganisms, parasites and viruses, preferably bacteria, growth and number can be limited. This ability can be characterized by a bacterial reduction of at least 0.1 log or 20% measured in a suspension, in a wound dressing or on a support. In the case the method of measurement of the growth and number reduction of contaminating and/or pathogenic agent leads to a potential standard deviation in the obtained values, the results should be interpreted strictly. This means that every time a measured value could be lower than the defined threshold due to the variability of measurement; the expected antibacterial effect is not fulfilled.

[0056] A first object of the invention is a light source device comprising a light emitting element for emitting a light having the following characteristics:

[0057] a wavelength ranging from 435 to 520 nm, and

[0058] a power density greater than 20 mW/cm.sup.2, the light source device (10) provides an effective fluence to any contaminating and/or pathogenic agent greater than 11 J/cm.sup.2.

[0059] According to FIG. 1, a light source device 10 comprising a light emitting element 12 for emitting a light having a wavelength ranging from 435 to 520 nm is proposed. The light source device 10 is able to emit light at wavelengths within the range of 435 to 500 nm, preferably within a specific dominant emission wavelength of 440-490 nm and preferably within a specific dominant emission wavelength of 450-460 nm. More particularly, the chosen dominant emission wavelength may be 450 or 453 nm.

[0060] Furthermore, the light source device 10 is configured to provide light to contaminating and/or pathogenic agent present on the support or medium C at irradiance and fluence (dose or energy density) able to at least inhibit this growth and number in said medium or support. The fluence at which light is provided to the contaminating and/or pathogenic agents present on the support or medium C corresponds to the specific conditions, particularly specific conditions of irradiance and exposure with a light source having a specific dominant emission wavelength; allowing to obtain the unexpected technical effect with regard to the prior art. Indeed, it was observed that monitoring the irradiance of the provided light allows having a growth and number-reductive effect on irradiated contaminating and/or pathogenic agents.

[0061] The growth and number reduction of contaminating and/or pathogenic agents may be performed on any support or in any medium, ex vivo or in vivo. Indeed, contaminating and/or pathogenic agents may be present in liquid medium such as used waters or the air, on any inert surfaces or in human or animal tissues, in particular on wounds.

[0062] The light source device 10 may be configured to provide light at a specific fluence and power density to any support or medium, and for example to human or animal skin tissue or to in vitro contaminating and/or pathogenic agents such as bacteria to provide the growth and number-reductive effect. Thus, this light source device 10 is more particularly useful in wound treatment. According to this embodiment, the light source device transmits the light onto the surface of a wound.

[0063] Depending on many interference means, as described above, disposed between the contaminating and/or pathogenic agent and the light source, the effective fluence of the light received by said agent may be lower than the fluence transmitted by the light emitting element. Indeed, it was also observed that a larger fluence has to be generally transmitted by the light emitting element 12 to provide a predetermined fluence of light to the contaminating and/or pathogenic agent on the support or medium C, i.e. an effective fluence of light adsorbed by the contaminating and/or pathogenic agent. Indeed, during the emission, a part of the light is adsorbed by other elements than the contaminating and/or pathogenic agent which induces a loss of light. Therefore, the light source device 10 is configured to provide light at a transmitted fluence so that the contaminating and/or pathogenic agent receives a predetermined fluence (also called effective fluence). Depending on the elements that can be present between the light emitting element and the target contaminating and/or pathogenic agent, the attenuation or absorption effect of the light may lead to an attenuation ranging from 20% to 60% or from 30% to 50% of the energy density, preferably around 45%.

[0064] To obtain the unexpected growth and number-reductive effect of the contaminating and/or pathogenic agent, the irradiance or power density is of at least 20 mW/cm.sup.2, particularly in the range from 20 to 400 mW/cm.sup.2, more particularly a power density ranging from 21 to 150 mW/cm.sup.2 and more particularly from 23 to 46 mW/cm.sup.2.

[0065] The effective dose or fluence received by the contaminating and/or pathogenic agent, in particular a bacteria of a wound or a given surface of skin tissue, may be of at least 11 J/cm.sup.2, and preferably from about 40 J/cm.sup.2 to about 600 J/cm.sup.2, or about 41 J/cm.sup.2 to about 590 J/cm.sup.2, or about 42 J/cm.sup.2 to about 580 J/cm.sup.2, or about 45 J/cm.sup.2 to about 570 J/cm.sup.2, about 50 J/cm.sup.2 to about 560 J/cm.sup.2, or about 55 J/cm.sup.2 to about 550 J/cm.sup.2, or about 60 J/cm.sup.2 to about 540 J/cm.sup.2, or about 65 J/cm.sup.2 to about 530 J/cm.sup.2, or about 70 J/cm.sup.2 to about 520 J/cm.sup.2, or about 75 J/cm.sup.2 to about 510 J/cm.sup.2, or about 80 J/cm.sup.2 to about 500 J/cm.sup.2, or any light dose in a range bounded by, or between, any of these values. Preferably, the effective fluence used to treat target contaminating and/or pathogenic agent, and preferably bacteria is greater than 40 J/cm.sup.2, preferably greater than 80 J/cm.sup.2.

[0066] As indicated above, the fluence (dose or energy density) notably depends on both irradiance (mW/cm.sup.2) and time. Therefore, obtaining the predetermined fluence may be accomplished by using a higher power light source, which may provide the needed energy in a shorter period of time, or a lower power light source may be used for a longer period of time. Thus, a longer exposure to the light may allow a lower power light source to be used, while a higher power light source may allow the treatment to be done in a shorter time.

[0067] The duration of radiation or light exposure administered to a medium or support containing the contaminating and/or pathogenic agent, may also vary. In some embodiments, the exposure ranges from at least 1 microsecond, 1 second, at least few seconds, or at least 30 minute, or at least 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48 minutes; or up to about 5 hour, 4 h, 3 h, 2 h, 1 h or, for any amount of time in a range bounded by, or between, any of these values.

[0068] According to a specific embodiment, the light source device is used in the growth and number reduction of contaminating and/or pathogenic agents under specific conditions. Particularly, it was observed that the growth and number-reductive effect occurs on contaminating and/or pathogenic agents when provided with an effective fluence greater than 11 J/cm.sup.2 with a power density of about 20 mW/cm.sup.2 during about 10 minutes to 2 h. Preferably, it was observed that the growth and number-reductive effect occurs on contaminating and/or pathogenic agents when provided with an effective fluence greater than 40 J/cm.sup.2 with a power density from about 23 mW/cm.sup.2 to about 80 mW/cm.sup.2 during about 30 minutes to 2 h.

[0069] According to a specific embodiment of the invention, the light source device is able to emit light continuously (for instance one time, providing specific fluence values), sequentially (for example many times, separated by defined latencies, providing specific fluence values) or by means of pulsations (for example one or many times, providing a specific fluence depending on opposite variations of irradiance and time of exposure values).

[0070] According to a specific embodiment, the ratio between the effective fluence and the power density of the light source device of the invention is greater than 1.7 preferably greater than 3. The ratio between the effective fluence and the power density of the light source device characterizes the energy regarding the irradiance received by the contaminating and/or pathogenic agent, preferably the bacteria. It is an indicator qualifying the performance of the treatment.

[0071] For thermal issues, light source device may be configured to irradiate the contaminating and/or pathogenic agent either continuously or in pulses. Indeed, pulsed light irradiation will typically be preferred than continuous light if there are some thermal issues; indeed, light source provides heating. The decision whether to use constant irradiation of pulsed light irradiation depends on the exact application and on the total desired irradiation. When the light exposure depends on the duration of a cycled light, the net light time may be determined by the sum of the duration of each pulse.

[0072] The light emitting element 12 is a device able to perform photobiomodulation. An example of such a light emitting element 12 is a light-emitting diode (LED or OLED, preferably LED), a LASER, or a lamp (such as filament lamp, gaz lamp) which is able to emit light at wavelengths within the ranges of 435 to 520 nm and having preferably a dominant emission wavelength comprised between 450-460 nm, as well as at a dominant emission wavelength of 450 or 453 nm. In the embodiment shown on FIG. 1, the light emitting element 12 comprises three light-emitting diodes. Alternatively, the light emitting element 12 may comprise one or more light-emitting diode (or lamp) able to emit a blue light having a wavelength ranging from 435 to 520 nm, having preferably a dominant emission wavelength comprised between 450 to 460 nm or having a dominant emission wavelength of about 450 or 453 nm.

[0073] For supplying electricity to the light emitting element 12, the light source device 10 may comprise a power source connected to the light emitting element 12. The power source may comprise an electric cable to connect to a power grid or a battery scavenger. Alternatively, the power source may be a battery, or a solar cell, preferably a battery. The light source device 10 is compact and able to communicate with a smartphone or a tablet thanks to a wireless communication protocol (Bluetooth or Bluetooth smart or Bluetooth Low Energy, NFC, Wifi, Lifi, Lora, Zigbee, preferably Bluetooth Low Energy).

[0074] For controlling the light emitting element 12, the light source device 10 may comprise at least one among a LED Driver, a sensor, a microchip processor, a control unit, a communication unit and an external port, an antenna, a memory.

[0075] A sensor may allow the light source device 10 to measure parameters of the contaminating and/or pathogenic agent. These parameters may be for example the temperature and the oxygenation level of the treated surface.

[0076] The microchip processor or the control unit may allow the light source device 10 to monitor the supply of electricity to the light emitting element 12 to guarantee an optimum or desired light exposure. For example, the microchip processor or the control unit may control whether the light exposure is continuous, discontinuous or in cycles as well as the frequency and the duration of the pulses depending on predetermined parameters or live parameters such as values measured by a sensor of the light source device 10.

[0077] Furthermore, a communication unit may allow a user to recover data from or transmit data to the light source device 10. For example, data may be transmitted to a smartphone or any other external device, notably an external device comprising a screen to display information useful to the user. The communication unit may be configured for wireless transmission or wired communication. In the case of a wired communication, the light source device 10 may comprise an external port connected to the communication unit for data transmission. Alternatively, the communication unit may be configured for both wireless and wired communication.

[0078] Moreover, the light source device 10 may be included in a light source assembly (not shown) which comprises a product adapted to be in contact with a surface to be treated, for example the skin or a wound formed on the skin. In this case, the light source device 10 is connected to the product for providing light to at least one contaminating and/or pathogenic agent of the skin or the wound.

[0079] For improving light effect, the light source assembly may be adapted to dispose the light emitting element 12 in a position wherein the light emitting element 12 is facing the support. In other words, the light source assembly is also adapted to place the light emitting element on the facing page of the support.

[0080] Furthermore, the light source device 10 may be configured so that light is irradiated to the contaminating and/or pathogenic agent or to the support or medium through the product. In doing so, the light source device 10 can irradiate to the contaminating and/or pathogenic agent or to the support or medium, preferably the support without direct contact.

[0081] The light source assembly may be configured to allow setting or predetermining of the distance between the light emitting element 12 and the support. Indeed, light intensity decreases with the square of the distance from the source of the light. For example, light 1 meter away from a source is four times as intense as light 2 meters from the same source. Therefore, setting the distance between the light emitting element 12 and the support allows monitoring the irradiance and thus the fluence provided to the said surface. The distance between the light emitting element 12 and the support may be predetermined from 0 to 50 mm, and preferably 0 to 20 mm in the case of a wound dressing for example. This distance could be larger depending on the targeted use. For example in the food processing industry, the distance between the light emitting element 12 and the support may be of several centimeters in the case of a lamp used alone for example.

[0082] For setting or predetermining the distance between the light emitting element 12 and the support, the dimension of the product may be chosen to predetermine or set the distance between the light emitting element 12 and the support or medium. Alternatively or in combination, the light source assembly may further comprise an adjustable element for adjusting the distance between the light emitting element 12 and the support.

[0083] The light source device 10 may also be configured so that the light emitting element 12 may be selectively orientated to better target the contaminating and/or pathogenic agent to be irradiated. This orientation or homogenization of the light emitting element 12 allows the irradiation to be more adapted to the geometry and the characteristics of any contaminating and/or pathogenic agent or to the treated surface, support or medium. These advantages become even more significant when the light source device 10 comprises a plurality of light emitting elements 12. In this case, the light emitting elements 12 may be orientated independently from each other to widen the irradiated area.

[0084] Furthermore, the light source device 10 may comprise a lens for focusing the light onto the target the support or medium to make the irradiation more precise.

[0085] The product may be one among a dressing, a strip, a compression means, a Band-Aid, a patch, a gel and a rigid or flexible support, a film-forming composition or similar. Furthermore, in an embodiment of the light source assembly, the product may be arranged so that the light emitting element 12 is disposed on the interior of the product or in its inferior or superior surface. In this embodiment, the product adapted to contact the skin or a wound is preferably a dressing. The dressing may comprise at least a hydrocolloid or an adhesive layer in contact with the skin or the wound.

[0086] The light source assembly may be of any size or shape. In one particular embodiment, the assembly may be 88 cm (or more 2020 cm for instance) in size. In another embodiment, the assembly may be 44 cm in size. The product may comprise an interior layer comprising a mesh material and a tissue gel. The mesh material allows exudate from a wound to which the dressing is applied to be absorbed into the dressing whilst allowing the tissue gel to flow through it so that it can be absorbed by a wound being treated.

[0087] For allowing the light source assembly to be reusable while avoiding repetitive cleanup, the product may be disposable and interchangeable. In other words, the product may be configured to be separated from the light source device 10 so that a same light source device 10 can be used several times without the need of a cleanup. It also allows changing the electronic elements included in the light source device 10 for maintenance, for example for recharging the battery.

[0088] A method for inhibiting growth and reducing number of contaminating and/or pathogenic agent, preferably bacteria is also proposed. In this respect, the present invention is also directed to a method for inhibiting growth and reducing number of contaminating and/or pathogenic agent, said method comprising exposing said contaminating and/or pathogenic agent to the light source device 10 and the light source assembly described above.

[0089] Contaminating and/or pathogenic agent or the support or medium are irradiated with a light at wavelengths comprised between 435 to 520 nm, and preferably having a dominant emission wavelength comprised between 450 and 460 nm. More particularly, the chosen dominant emission wavelength may be of 450 or 453 nm. The method may be performed in vivo or in vitro. Bacteria, and more generally contaminating and/or pathogenic agent may be in culture or directly from a human or animal tissue.

[0090] To reduce their growth and number, contaminating and/or pathogenic agents may be irradiated to receive an effective fluence greater than 11 J/cm.sup.2, preferably greater than 40 J/cm.sup.2 and more preferably greater than 80 J/cm.sup.2.

[0091] To reduce the growth and number of contaminating and/or pathogenic agents, light emitting source used in this method is greater than 20 mW/cm.sup.2 and preferably comprised between 23 and 400 mW/cm.sup.2, more particularly a power density ranging from 21 to 150 mW/cm.sup.2 and more particularly from 23 to 46 mW/cm.sup.2.

[0092] More generally, the irradiation of light performed in this method may be set using all the different values of fluence, power intensity and time described above for the light source device 10 and the light source assembly.

[0093] This method allows to benefit from the same effects as described above for the light source device 10 and the light source assembly. Particularly, the present method allows to obtain the unexpected technical effect of light consisting in at least inhibiting growth and reducing number of contaminating and/or pathogenic agent.

[0094] In particular, the method according to the invention is very useful for reducing growth and number of contaminating and/or pathogenic agents, for the treatment of fluid or liquid medium such as respectively the air or used waters, for surface decontamination or disinfection of wounds, mucosa and skin, or such as packing, wrapping, food products, and cleaning and/or domestic devices preferably through a photobiomodulation means. More specifically, the method according to the invention is very useful for reducing growth and number of contaminating and/or pathogenic agents of wound, skin or mucosa

[0095] In a specific embodiment the present invention also discloses a method for inhibiting growth and reducing number of contaminating and/or pathogenic agent comprising exposing said contaminating and/or pathogenic agent to a light source device (10) comprising a light emitting element (12) for emitting a light having a wavelength ranging from 435 to 520 nm, the light source device (10) providing an effective fluence to any contaminating and/or pathogenic agent greater than 11 j/cm.sup.2, wherein the exposure of the contaminating and/or pathogenic agent to the light is discontinuous.

[0096] It is indeed of the merit of the inventors to have discovered that the inhibition of growth and/or the reduction of the number of contaminating and/or pathogenic agent is unexpectedly enhanced when the contaminating and/or pathogenic agent is exposed discontinuously to a light having a wavelength ranging from 435 to 520 nm, compared to a continuous exposure. In particular, the enhanced inhibition of growth and/or reduction of the number of contaminating and/or pathogenic agent can be obtained by subjecting the agent to the same light having a wavelength ranging from 435 to 520 nm, and adjusting either the power density of each sequence of irradiation or the total duration of exposure to the light so that the total effective fluence received by the agent during the whole treatment remains the same.

[0097] By discontinuous exposure, it should be understood that the light is sequentially emitted and disrupted at least twice, preferably at least 10 times, more preferably at least 15 times. Discontinuous exposure also means any cycled or pulsed exposure, that should be understood as the sequential emission and disruption of light defined by a specific frequency and a specific period of time.

[0098] In a particular embodiment, each sequence of emission/disruption of light lasts for a period of time which can be an attosecond, a femtosecond, a picosecond, a nanosecond, a microsecond, a millisecond, a second, a minute, one hour, one day. Each sequence can also be defined by its frequency in Hertz, milli-Hertz, micro-Hertz, kilo-Hertz, mega-Hertz, giga-Hertz or tera-Hertz, the frequency being the inverse of the period. According to a specific embodiment, each sequence is characterized by a frequency comprised between 0.0001 and 100 Hz, preferably between 0.001 and 10 Hz.

[0099] The sequences of emission/disruption may be symmetrical in the sense that the duration of light emission and the duration of light disruption is the same. Alternatively, the sequences of emission/disruption may be asymmetrical in the sense that the duration of light emission and the duration of light disruption is different.

[0100] Each sequence of emission/disruption can be defined by a light exposure ratio (or as duty cycle), corresponding to the ratio between the duration of light emission and the duration of light disruption. The light exposure ratio is expressed as a percentage and is comprised between 0 and 100%, the ends of the range (0% and 100%) being excluded. A light exposure ratio close to 0% means that the light is disrupted during almost the entire sequence. A light exposure ratio close to 100% means that the light emits during almost the entire sequence. According to a specific embodiment, the light exposure ratio could be comprised between 20 and 80, or between 45 and 55.

[0101] The present invention also describes a light source device for use for the in vivo growth and number reduction of microorganism and/or virus on a support or in a medium.

[0102] The present invention also describes a light source assembly containing a light source device for use for the in vivo growth and number reduction of contaminating and/or pathogenic agent on a support or in a medium

[0103] In another aspect, the invention is directed to the light source device or to the light source assembly described above, for use in reducing contaminating and/or pathogenic agent growth and number, and in particular for a use as a bactericide.

[0104] The invention will be illustrated further by the following examples:

Example 1: Effect of the Blue Light on the Growth and Number Reduction of S. aureus

Bacteria Cells in Suspension

[0105] 1 mL, of a S. aureus (ATCC 6538) solution at a concentration of 1.5 to 510.sup.7 CFU/ml were inoculated in Petri dishes comprising 9 mL of a mixture of 50% of buffered peptone water (0.1%) and 50% foetal veal serum (Simulated Wound Fluid or SWF), bacteria concentration was 1.510.sup.6 CFU/mL in the Petri dish.

[0106] Then, the Petri dishes inoculated with the bacteria are treated by a blue light.

Light Treatment

[0107] For the light treatment, OSRAM GD PSLR31.13 is used, with dominant emission wavelength of 450 nm (blue light). Dressings were directly irradiated with a power density of 23 or 46 mW/cm.sup.2.

Bacterial Enumeration

[0108] Bacterial enumeration was conducted before light treatment, and after exposure to light to observe the reductive effect of light treatment on bacterial growth and number.

Results

[0109]

TABLE-US-00001 TABLE 1 bacterial growth and number reduction observed after irradiation of S. aureus cells in suspension in SWF Power Effective Time of Bacterial Bacterial density Fluence exposure reduction reduction (mW/cm.sup.2) (J/cm.sup.2) (min) Ratio.sup.(1) (Log) (%) 23 166 120 7.21 0.26 45 23 248 180 10.78 0.74 81 23 331 240 14.390 1.15 Superior to 90 23 414 300 18 1.5 Superior to 90 46 331 120 7.21 5.58 Superiorto 99 .sup.(1)Ratio between the effective fluence and the power density

[0110] The results show that the exposure of S. aureus to blue light (450 nm) with energy densities of greater than 41 J/cm.sup.2, significantly inhibits bacterial growth and number and proliferation which well shows that such irradiation with blue light can be used to inhibit bacterial development on solid supports, and in particular on wounds and injuries.

Example 2: Effect of the Blue Light on the Growth and Number Reduction of P. aeruginosa

Bacteria Cells Immobilized in Wound Dressings

[0111] P. aeruginosa (ATCC 15442) at a concentration of 1.5 to 510.sup.7 CFU/mL were inoculated on the surface of pre-wetted dressings. The concentration of bacteria was about 510.sup.6 CFU/dressing.

[0112] Then, the dressings inoculated with the bacteria are treated by a blue light.

Light Treatment

[0113] For the light treatment, OSRAM GD PSLR31.13 is used, with dominant emission wavelength of 450 nm (blue light). Dressings were directly irradiated with a power density of 23 or 46 mW/cm.sup.2.

Bacterial Enumeration

[0114] Bacterial enumeration was conducted before light treatment, and after exposure to light to observe the reductive effect of light treatment on bacterial growth and number.

Results

[0115]

TABLE-US-00002 TABLE 2 bacterial number and growth reduction observed after irradiation of inoculated dressings with P. aeruginosa power Effective Time of Bacterial Bacterial density Fluence exposure reduction reduction (mW/cm.sup.2) (J/cm.sup.2) (mins) Ratio.sup.(1) (Log) (%) 23 10 7.5 0.43 0.02 4 23 41 30 1.78 0.14 27 23 83 60 3.60 0.39 59 23 166 120 7.21 1.04 Superior to 90 23 414 300 18 4.56 Superior to 99 46 166 60 3.60 3.53 Superior to 99 46 414 150 9 4.74 Superior to 99 .sup.(1)Ratio between the effective fluence and the power density

[0116] The results show that the exposure of P. aeruginosa to blue light (450 nm) with energy densities greater than 41 J/cm.sup.2, significantly reduces bacterial growth and number which well shows that such irradiation with blue light can be used to inhibit bacterial development on solid supports, and in particular on wounds and injuries.

[0117] In conclusion, the results exhibit that the exposure of bacteria (whatever the considered species, Gram-positive or Gram-negative) to blue light (specifically at 450 nm or 453 nm) with energy densities greater than 11 J/cm.sup.2, preferably greater than 40 J/cm.sup.2 (more precisely, 41 J/cm.sup.2), and irradiance values greater than 20 mW/cm.sup.2, significantly reduces the bacterial growth and number.

Example 3: Effect of the Blue Light on the Growth and Number of E. coli

Bacterial Culture

[0118] 0.5 mL of an Escherichia coli (strain K12) (Taxon identifier: 83333) solution at a concentration of 110.sup.6 CFU/mL in NaCl 0.9% were inoculated in 4.5 mL nutrient broth (8 g/L (Merck)). Afterwards, a dilution series is prepared and then after irradiation by a blue light, bacteria were seeded on plates and number of colonies was counted 24 hours later.

Light Treatment

[0119] For the light treatment, Lumileds Luxeon Rebel LXML-PR01-0275 from Koninklijke Philips N. V. (Eindhoven/Netherlands) was used, with a dominant emission wavelength of 453 nm (blue light).

[0120] Suspensions were directly irradiated with a power density of 10 or 23 mW/cm.sup.2.

Bacterial Enumeration

[0121] Bacterial enumeration was conducted before light treatment, and after incubation to observe the inhibitory effect of light treatment on bacterial growth and number.

Results

[0122] Results are shown in FIGS. 2 and 3.

[0123] Nb: [0124] BLI means Blue light irradiation [0125] Control does not receive any light irradiation whatever the exposure time considered [0126] Numbers following BLI or control mention, express time (with exposure to blue light (BLI) or without exposure (control)) after which colony count has been made.

TABLE-US-00003 TABLE 3 Correspondence between time of exposure, power density used and fluence definition for each condition power Effective density Time of Fluence (mW/cm.sup.2) exposure (J/cm.sup.2) 23 30 min 41 23 60 min 83 23 120 min 166 10 30 min 18 10 60 min 36 10 120 min 72

[0127] FIG. 2 represents a histogram comparing the effect on colony count of E. coli in blue light irradiation conditions (453 nm, defined as BLI) Vs without irradiation (defined as control), and for irradicance values of 23 mW/cm.sup.2.

[0128] FIG. 3 represents a histogram comparing the effect on colony count of E. coli in blue light irradiation conditions (453 nm, defined as BLI) Vs without irradiation (defined as control), and for irradicance values of 10 mW/cm.sup.2.

[0129] The results show that the exposure of E. coli to blue light (453 nm) with a device having the irradiance feature of 10 and 23 mW/cm.sup.2 induce respective different issues too. More precisely, blue light irradiation of E. coli at 23 mW/cm.sup.2 (FIG. 2) induces a drastic reduction of the number of colonies counted whatever the time of exposure. On the contrary, there is no significant effect on the colony number measured between E. coli treated with blue light (10 mW/cm.sup.2) and control group for the same time of exposure (FIG. 3).

[0130] Indeed, examples 1 to 3 show that a device comprising a light emitting element for emitting a light having the following characteristics:

[0131] a wavelength ranging from 435 to 520 nm, and

[0132] a power density greater than 20 mW/cm.sup.2,

[0133] the light source device provides an effective fluence to any contaminating and/or pathogenic agent greater than 11 J/cm.sup.2 exhibit a specific and surprising effect on the growth and number reduction of contaminating and/or pathogenic agent, preferably bacteria, whatever the specie (Gram-positive or Gram-negative) of bacteria.

Example 4: Effect of the Cycled Blue Light on the Growth and Number of K. pneumoniae, P. Aeruginosa and E. coli

Bacterial Culture

[0134] 0.5 mL of an Escherichia coli (strain K12) (Taxon identifier: 83333) solution at a concentration of 110.sup.6 CFU/mL in NaCl 0.9% were inoculated in 4.5 mL nutrient broth (8 g/L (Merck)). Afterwards, a dilution series is prepared and then after irradiation by a blue light, bacteria were seeded on plates and number of colonies was counted 24 hours later.

Light Treatment

[0135] For the light treatment, Lumileds Luxeon Rebel LXML-PR01-0275 from Koninklijke Philips N. V. (Eindhoven/Netherlands) were used, with a dominant emission wavelength of 453 nm (blue light).

[0136] Suspensions were directly irradiated: [0137] with a continuous exposure to light having a power density of 23 mW/cm.sup.2 and [0138] with a discontinuous exposure to light with a power density of 23 mW/cm.sup.2 characterized by a light exposure ratio of 50% and a frequency of 0.02 Hertz, and a total duration of exposure doubled compared to the continuous exposure.

[0139] The light source device provides an effective fluence to any contaminating and/or pathogenic agent greater than 11 J/cm.sup.2.

Bacterial Enumeration

[0140] Bacterial enumeration was conducted before light treatment, and after incubation to observe the inhibitory effect of light treatment on bacterial growth and number.

Results

[0141] Results are presented in FIGS. 4, 5 and 6.

[0142] FIG. 4 represents two curves comparing the effect on colony count of K. pneumoniae in continuous blue light irradiation conditions (453 nm) Vs discontinuous blue light irradiation conditions (453 nm, light exposure ratio of 50%, frequency of 0.02 Hertz) and for irradiance values of 23 mW/cm.sup.2.

[0143] FIG. 5 represents two curves comparing the effect on colony count of P. aeruginosa in continuous blue light irradiation conditions (453 nm) Vs discontinuous blue light irradiation conditions (453 nm, light exposure ratio of 50%, frequency of 0.02 Hertz) and for irradiance values of 23 mW/cm.sup.2.

[0144] FIG. 6 represents two curves comparing the effect on colony count of E. coli in continuous blue light irradiation conditions (453 nm) Vs discontinuous blue light irradiation conditions (453 nm, light exposure ratio of 50%, frequency of 0.02 Hertz) and for irradiance values of 23 mW/cm.sup.2.

[0145] The results show that the exposure of K. pneumoniae, P. aeruginosa or E. coli to discontinuous blue light with a device having a power density of 23 mW/cm.sup.2 and a duration of treatment doubled, induces an enhanced reduction of the number of colony counted compared to the same bacteria treated continuously with the same blue light.

Example 5: Effect of the Blue Light on the Growth and Number Reduction of S. aureus

Bacteria Cells Immobilized on Rigid and Inert Metal Plate (Support) [Adaptation of the French Standard NF EN 13697: 2015]

[0146] S. aureus (ATCC 6538) at a concentration of 1.5 to 510.sup.8 CFU/mL were inoculated on the surface of a rigid and inert metal plate.

[0147] Then, the support inoculated with the bacteria is treated by a blue light.

[0148] Samples: n=3

Light Treatment

[0149] For the light treatment, OSRAM GD PSLR31.13 is used, with dominant emission wavelength of 450 nm (blue light). Support is directly irradiated with a power density of 23 or 80 mW/cm.sup.2.

Bacterial Enumeration

[0150] Bacterial enumeration was conducted before light treatment, and after exposure to light to observe the reductive effect of light treatment on bacterial growth and number.

TABLE-US-00004 TABLE 4 bacterial growth and number reduction observed after irradiation of S. aureus cells on a support Power Effective Time of Bacterial Bacterial density fluence exposure reduction reduction (mW/cm.sup.2) (J/cm.sup.2) (mins) Ratio.sup.(1) (Log) (%) 80 24 5 0.3 0.16 +/ 0.11 27 +/ 20 23 41 30 1.78 0.37 +/ 0.11 58 +/ 20 23 166 166 7.2 1.01 +/ 0.26 Superior to 99 80 240 240 3 2.43 +/ 0.39 Superior to 99 .sup.(1)Ratio between the effective fluence and the power density
Contrary to the tests conducted in example 1 and/or 2, the results obtained with the present method are expressed with a standard deviation in the logarithmic scale reduction.
This however does not change the interpretation of the results:
The reduction of bacterial growth and number observed for an effective fluence of 24 J/cm.sup.2 and a power density of 80 mW/cm.sup.2, and so, for a measured ratio of 0.3 are clearly non-significant as stated by the definition given of growth and number reduction of contaminating and/or pathogenic agent, whatever the method used.
The results show that the expected technical effect for growth and number reduction of bacteria is obtained for ratios of at least of 1.7 or greater and preferably at least of 3.

Example 6: Effect of the Pulsed Blue Light on the Growth and Number Reduction of S. aureus and P. Aeruginosa

Bacteria Cells Immobilized on Rigid and Inert Metal Plate (Support) [Adaptation of the French Standard NF EN 13697: 2015]

[0151] S. aureus (ATCC 6538) or P. aeruginosa (ATCC 15442) at a concentration of 1.5 to 510.sup.8 CFU/mL were inoculated respectively on the surface of a rigid and inert metal plate.

[0152] Then, the inoculated support with the bacteria is treated by a pulsed blue light. Conditions of this used pulsed blue light are: frequency of 3 Hz, duty cycle of 80%.

[0153] Samples: n=1

Light Treatment

[0154] For the light treatment, OSRAM GD PSLR31.13 is used, with a dominant emission wavelength of 450 nm (blue light). Support is directly irradiated with a power density of 23, 198, 300 or 400 mW/cm.sup.2.

Bacterial Enumeration

[0155] Bacterial enumeration was conducted before light treatment, and after exposure to light to observe the reductive effect of light treatment on bacterial growth and number.

TABLE-US-00005 TABLE 5 Bacterial growth and number reduction observed after irradiation of S. aureus cells on a support Power Effective Time of Bacterial Bacterial density fluence exposure reduction reduction (mW/cm.sup.2) (J/cm.sup.2) (mins) Ratio.sup.(1) (Log) (%) 23 41 30 1.78 0.67 Superior to 90 198 166 14 0.84 2.22 Superior to 99 133 240 30 1.8 1.65 Superior to 99 300 240 13.5 0.8 4.11 Superior to 99 .sup.(1)Ratio between the effective fluence and the power density

TABLE-US-00006 TABLE 6 Bacterial growth and number reduction observed after irradiation of P. aeruginosa cells on a support Power Effective Time of Bacterial Bacterial density fluence exposure reduction reduction (mW/cm.sup.2) (J/cm.sup.2) (mins) Ratio.sup.(1) (Log) (%) 23 41 30 1.78 1.12 Superior to 99 198 166 14 0.84 2.27 Superior to 99 133 240 30 1.8 2.82 Superior to 99 400 240 10 0.6 4.94 Superior to 99 .sup.(1)Ratio between the effective fluence and the power density
The results exhibit a significant and drastic effect over the reduction of bacteria growth and number when submitted to an exposure of a pulsed blue light. The results seem equivalent between each kind of tested bacteria strain. Compared to the results obtained in example 5 (continuous light), the pulsed blue light shows an enhanced effect in the reduction of bacteria growth and number whatever the ratio for a specific and defined effective fluence used.