Light stimulation system for a biological sample

Abstract

The invention relates to a light stimulation system for a biological sample (ECH), comprising: A light source (2) capable of emitting a light beam, called input light beam (F1), A closed enclosure (3) intended to receive at least one container (1) in which the biological sample is placed, The system comprising an optical device (5), The system comprising an optical guide (4) connected on one side to said light source (2) to receive said input light beam (F1) and on the other side to said optical device (5), the optical guide (4) being arranged to guide the input light beam emitted by the light source to the optical device (5) and emit a light beam, called output light beam (F2), Said optical device being configured to generate a parallel stimulation light beam (F4) with a determined constant cross-section, from said output light beam (F2).Figure to be published with the abbreviation: Figure 1.

Description

Title of the invention: Light stimulation system for a biological sample Technical field of the invention

[0001] The present invention relates to a light stimulation system for a biological sample. State of the art

[0002] Photobiomodulation or phototherapy are rapidly developing techniques that aim to cure or slow the progression of a disease using light. Photobiomodulation covers a wide range of applications, including the treatment of neurodegenerative diseases, fibromyalgia, and pain.

[0003] To evaluate the effectiveness of photobiomodulation on a biological sample such as cells, it is known to place Petri dishes containing the cells on a light panel, this panel being itself placed in a closed chamber to maintain a temperature-controlled environment (e.g., 37 °C) and humidity (80–90% humidity). The light panel thus generates a light flux through each Petri dish placed on the panel.

[0004] However, in practice, this configuration generates some drawbacks: During extended tests lasting several hours, the electronic circuit board of the light panel tends to overheat, increasing the temperature inside the chamber and potentially damaging the cells. This necessitates placing the light panel on a cooling panel (for example, one with temperature-controlled water circulation) to dissipate the heat generated by the circuit board. Setting the internal temperature and managing the water circulation of the cooling panel then becomes difficult, resulting in an unstable operating point. Because the cooling panel's set temperature is low to efficiently dissipate heat, and the chamber's humidity is set to approximately 80%, the dew point is exceeded, and condensation becomes a problem (oxidation, electrical hazards, and humidity levels). - The entire illumination panel emits light, which is not necessary as only the Petri dishes need to be illuminated; this leads to light reflections which can affect the biological study and to overconsumption which affects the temperature inside the enclosure. - The light-emitting diodes (LEDs) in the lighting panel are known to age rapidly with temperature. For example, one might have

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[0010]

[0011] a loss of luminous efficiency of 10% per year in intensive use, thus requiring frequent replacement of the lighting panel to maintain acceptable performance. The aim of the invention is to propose a system used for the light stimulation of a biological sample, this system having a configuration that overcomes the disadvantages of the prior art. Statement of the invention This goal is achieved through a light stimulation system applied to a biological sample, comprising: - A light source capable of emitting a light beam, called the input light beam, - A closed enclosure designed to hold at least one container in which the biological sample is placed, - With the light source placed outside the enclosure, - The system includes an optical device placed inside the enclosure, - The system comprising an optical guide connected on one side to said source luminous to receive said input light beam and on the other side on said optical device, the optical guide being arranged to guide the input light beam emitted by the light source to the optical device and to emit a light beam, said output light beam, to the optical device, - Said optical device being configured to generate a parallel light beam for stimulation of the biological sample with a constant cross-section determined from said output light beam. According to one particular feature, the optical device includes an optical assembly configured to generate a divergent light beam from the output light beam and an off-axis parabolic mirror positioned relative to said optical assembly to reflect said divergent light beam and form said parallel stimulation light beam. According to another feature, the system includes means for adjusting the position of said optical assembly relative to that of the off-axis parabolic mirror. According to another feature, the system includes means for adjusting the position of the off-axis parabolic mirror relative to that of the optical assembly. According to another feature, the system includes means for adjusting the orientation of said optical assembly relative to the off-axis parabolic mirror. According to another feature, the system includes means for adjusting the orientation of the off-axis parabolic mirror relative to the optical assembly.

[0012] According to another feature, the light source is a regulated laser source.

[0013] According to another feature, the system includes a mask arranged at the output of the optical device for shaping the cross-section of the parallel stimulation light beam.

[0014] According to another feature, the waveguide includes a splitter, arranged to separate said input light beam into at least two output light beams, the system comprising at least two optical output light beam shaping devices arranged in parallel, configured to generate two distinct parallel stimulation light beams.

[0015] According to another feature, the closed enclosure is an incubator.

[0016] The invention also relates to a method of light stimulation of a biological sample, implemented using the system as defined above, the method comprising the following steps: - Position within said closed enclosure a container in which is placed said biological sample to be stimulated, said container having an illumination window having an illumination section through which a light beam can penetrate, this light beam being a parallel light beam for stimulating the biological sample, - Configure the optical device to obtain the parallel stimulation light beam with a constant surface area greater than or equal to the illumination area of ​​the container's illumination window, - Activate said light source to emit the input light beam inside the optical guide and obtain the output light beam to be applied to the optical device for shaping this beam.

[0017] According to one particular feature, the container is a Petri dish. Brief description of the figures

[0018] Other features and advantages will become apparent in the detailed description that follows, given in relation to the accompanying drawings in which: - Fig. 1 represents schematically the light stimulation system of a biological sample, according to the invention; - Fig. 2 schematically shows the architecture of the final part of the stimulation system of the invention; - Fig. 3 shows the principle of creating the stimulation light beam that illuminates the container containing the biological sample; - Fig. 4 shows, by way of perspective view, an example of the realization of the optical device used in the system of the invention; - Figure 5 schematically shows an advantageous implementation of the light stimulation system for a biological sample according to the invention; - Fig. 6 shows, schematically, a variant embodiment of the optical device used in the system of the invention;

[0019] Detailed description of at least one embodiment

[0020] The invention relates to the light stimulation of an ECH biological sample. By ECH biological sample, we mean, for example, cells of a living being, but also any other animal or plant substance for which light stimulation could have an effect.

[0021] The invention relates more particularly to cell culture, more particularly to the influence of light on cell culture and to monitoring the effect of light on cell culture. The terms "light" or "light beam" used below refer to any electromagnetic radiation with wavelengths ranging from ultraviolet to far-infrared, including visible light. Container

[0022] [Fig.3]

[0023] The ECH biological sample is placed in a container 1. This container 1 has a side wall and a bottom wall and can be open at the top or closed by a wall transparent to one or more wavelengths of the light beam emitted by the light source of the system. The area traversed by the light beam defines an illumination window 10 of the ECH biological sample. This illumination window 10 has a cross-section delimiting said area traversed by the light beam. This cross-section is advantageously circular. However, it will be seen below that this cross-section could be different and arbitrary, with a slight adaptation of the system.

[0024] Container 1 is for example made in the form of a Petri dish.

[0025] The light stimulation system of the invention mainly comprises: - A light source 2; - A speaker 3; - An optical guide 4; - An optical device 5; Light source

[0026] [Fig.1]

[0027] [Fig.2]

[0028] The system includes at least one light source 2. This light source 2 is powered to generate a light beam, referred to herein as the input light beam Fl.

[0029] The light source 2 can consist of one or more light-emitting diodes or advantageously of at least one laser diode.

[0030] The light source 2 is advantageously regulated in intensity.

[0031] In the field of photobiomodulation, the light source 2 is chosen to emit at a wavelength between 600nm and 1000nm.

[0032] In one embodiment, a control box 20 is used to supply current to a laser diode with a wavelength of 670 nm, emitting a maximum of 1.3 W. The current delivered by the power supply is on the order of 1 ampere. This same control box 20 allows for temperature regulation of the laser diode, which is mounted on a dedicated mechanism.

[0033] It should be noted that the Laser diode emits the input light beam Fl which is very divergent and that it is therefore necessary to refocus the beam with a set of lenses 21 to guide the light efficiently towards an optical guide (see below), the numerical aperture of the set of lenses being less than the numerical aperture of the optical guide 4 for optimal coupling.

[0034] According to the invention, the light source 2 is positioned outside the closed enclosure 3. Closed enclosure

[0035] [Fig.1]

[0036] [Fig.2]

[0037] The system comprises a closed enclosure 3 in which is positioned said container 1 receiving the biological sample ECH.

[0038] This enclosure 3 is hermetically sealed. In the context of cell culture, the internal space of the enclosure 3 is advantageously regulated in terms of temperature and humidity to obtain optimal conditions for cell growth. For example, the temperature can be regulated at 37°C and the humidity at approximately 80%. A specific control unit can be configured to manage the temperature and humidity levels inside the enclosure 3.

[0039] The enclosure 3 is, for example, an incubator. This incubator may include at least one sealed passage 30 formed through one of its walls, this passage being adapted to insert an optical guide 4.

[0040] Advantageously, the enclosure is closed so as to have walls that are completely opaque to external light and to form an internal volume that is as dark as possible.

[0041] Advantageously, the internal surface of the enclosure can be covered with a material that absorbs the wavelengths of photobiomodulation, in order to avoid secondary reflections that disrupt the stimulation. Optical guide

[0042] [Fig.1]

[0043] [Fig.2]

[0044] To direct the incoming light beam Fl emitted by the light source 2 into the interior of the enclosure 3, the system includes an optical guide 4, for example an optical fiber.

[0045] As indicated above, in the case of a light source of the Laser diode or light-emitting diode type which emits a very divergent beam, it may be necessary to use a set of lenses at the entrance of the optical guide 4 and to ensure that the numerical aperture of the lens is less than the numerical aperture of the optical guide for optimal coupling.

[0046] The optical guide 4 penetrates the enclosure 3, via the dedicated through-hole 30. The incoming light beam Fl emitted by the light source 2, located outside the enclosure, is therefore routed into the enclosure via the optical guide 4.

[0047] It should be noted that the optical guide 4 has flexibility characteristics allowing it to be slightly curved and manipulated, facilitating the overall setup of the system. Optical device

[0048] [Fig.1]

[0049] [Fig.2]

[0050] [Fig.3]

[0051] [Fig.4]

[0052] The optical device 5 is positioned inside the enclosure 3, at the output of the optical guide 4. Its function is to recover the light beam obtained at the output of the optical guide and called the output light beam F2, in order to shape this beam.

[0053] The optical device 5 is configured to shape the output light beam F2 in order to obtain the parallel stimulation light beam F4 of the desired ECH biological sample.

[0054] According to the invention, the objective is indeed to obtain a parallel light beam of stimulation F4 having a constant, advantageously circular, cross-section over its entire length, between the optical device 5 and the container 1 receiving the biological sample ECH.

[0055] The circular section of the beam F4 obtained is advantageously greater than or equal to the circular section of the illumination window 10 of the container 1.

[0056] The optical device 5 comprises an optical assembly 50 configured to generate a diverging light beam F3 from the output light beam F2 and an off-axis parabolic mirror 51 for receiving said diverging light beam F3 for the reflect and form said parallel light beam of stimulation F4.

[0057] The optical assembly 50 can be composed of two converging lenses positioned in series in a suitable manner and not in contact. Upon exiting the second lens, the resulting beam first converges towards a point source, thus forming a secondary light source 7. The optical assembly 50 is designed so that this secondary source 7 is positioned at the focal length of the off-axis parabolic mirror 51, which ensures that the beam F4 exiting the mirror 51 is parallel and not divergent. This secondary source 7 is divergent in the direction of the off-axis parabolic mirror 51. The optical assembly 50 therefore makes it possible to create this intermediate diverging secondary source 7 from the output light beam F2.

[0058] As a reminder, an off-axis parabolic mirror 51 is a known optical device, having a curved reflecting surface with a parabolic profile. It has the capacity to reflect a parallel light flux from a diverging light source.

[0059] At the output of the optical guide 4, the optical assembly 50 and its position must be chosen so that the divergence of the generated light beam F3 is sufficient to illuminate a large part of the off-axis parabolic mirror 51 and to ensure that a reflected light beam F4 used for stimulation is of constant and sufficient cross-section compared to the cross-section of the illumination window 10 of the container 1. In other words, the optical assembly 50 must be adapted to focus the light beam and form the secondary source 7 corresponding to the focal length of the off-axis parabolic mirror.

[0060] By way of example, an off-axis parabolic mirror of 3 inches (76.2 mm) will illuminate a conventional Petri dish.

[0061] The parallel light beam of stimulation F4 generated allows for homogeneity of illumination over the entire illumination window 10 of the container 1, and for only said container 1 to be illuminated, provided of course that the diameter of the off-axis parabolic mirror 51 is chosen greater than or equal to the diameter of the illumination window 10 (for example the diameter of the Petri dish).

[0062] Advantageously, as shown in [Fig. 4], the optical device 5 can be made in a single optical block comprising a support 52 on which the optical assembly 50 and the off-axis parabolic mirror 51 are arranged. The optical assembly 50 can in particular be slidably mounted in said support 52 to adjust its position relative to the off-axis parabolic mirror 51. Similarly, it would also be possible to adjust the position of the off-axis parabolic mirror.

[0063] Furthermore, means could be provided for adjusting the orientation of the optical assembly 50 and / or the off-axis parabolic mirror 51 in order to be able to orient them relative to each other.

[0064] If the section of the illumination window 10 of the container is not circular or if the If the parallel stimulation light beam F4 has a cross-section that is too large compared to that of the illumination window 10 of the container, the system may include a mask to modify the cross-section of the parallel stimulation light beam F4 so that it closely matches the shape of the illumination window 10 of the container. In this case, it is understood that the invention does not necessarily apply to cases where the illumination window 10 of the container has a circular cross-section. System layout

[0065] [Fig.1]

[0066] [Fig.2]

[0067] [Fig.3]

[0068] [Fig.4]

[0069] As indicated above, the light source 3 is positioned outside the enclosure 3.

[0070] The optical guide 4 is connected to the light source to direct the incoming light beam emitted by the source into the interior of the enclosure.

[0071] On the other side, the optical guide 4 is connected to the optical assembly 50 of the optical device 5. The light beam F2 obtained at the output of the optical guide 4 is sent to the optical assembly 50.

[0072] Optical connectors are provided to connect each end of the optical guide 4.

[0073] The optical assembly 50 allows the diverging source to be generated, creating the diverging light beam F3 in the direction of the off-axis parabolic mirror 51.

[0074] The off-axis parabolic mirror 51 receives the diverging light beam F3 and reflects it to obtain the desired parallel stimulation light beam F4, destined for the container 1.

[0075] The container 1 is for example placed on a first flat support 60 present in the closed enclosure 3, its illumination window 10 then being parallel to this first support.

[0076] The optical device can be fixed via its support 52 on a plate mounted parallel to the support 60 supporting the container 1, so that the off-axis parabolic mirror 51 emits the parallel stimulation light beam F4 in a direction perpendicular to the illumination window 10. This plate can support several optical devices 5 in parallel, in order to be able to process several samples in parallel.

[0077] Since the light beam is directed to the optical device 5 by the optical guide 4, it is not necessary to specifically orient the light source 2 with respect to the optical device 5, which facilitates the setting up of the system. Implementation variations

[0078] [Fig.5]

[0079] [Fig.6]

[0080] An advantageous embodiment illustrated in [Fig. 5] allows, using a single light source 2, the illumination of several containers 1. To achieve this, the system incorporates a splitter 40 arranged on the optical guide 4, the function of which is to divide the input light beam Fl emitted by the light source 2 into the input of the optical guide 4 into several output light beams. The system thus comprises several optical devices 5_1, 5_2 in parallel, each responsible for generating a distinct parallel stimulation light beam F4_1, F4_2 directed at a particular container 1. Several biological samples ECH1, ECH2 are thus optically stimulated in parallel.

[0081] Another embodiment shown in [Fig. 6] lies in the design of the optical device. According to this embodiment, the diverging source 500 (created by the optical assembly 50) is positioned in the off-axis parabolic mirror 51 (which is then drilled) and a reflecting mirror 53 (plane mirror) is added, which then reflects the incident diverging beam back towards the off-axis parabolic mirror 51. An optical fiber can be used to carry the light to the point forming the diverging source 500. This solution is more complex to implement but also more compact. Benefits

[0082] The invention thus offers numerous advantages, including: - It allows an area of ​​interest to be illuminated identically at every point so that each biological cell is stimulated with the same intensity and the same incidence of background light; - It makes it possible to solve the thermal problems present in the closed enclosure, by moving the light source and its control to the outside; - It allows for the creation of a homogeneous beam that perfectly coincides with the area to be illuminated; - It allows several biological samples to be illuminated in parallel, with identical light beams; - It is simple to implement and can offer adjustment possibilities taking into account the dimensions of the areas to be illuminated;

Claims

Claims

1. System for light stimulation of a biological sample (ECH), comprising: - A light source (2) capable of emitting a light beam, called the input light beam (Fl), - A closed enclosure (3) intended to receive at least one container (1) in which the biological sample is placed, - Characterized in that: - The light source (2) is placed outside the enclosure (3), - The system comprises an optical device (5) placed inside the enclosure (3), - The system comprises an optical guide (4) connected on one side to said light source (2) to receive said input light beam (Fl) and on the other side to said optical device (5), the optical guide (4) being arranged to guide the input light beam emitted by the light source to the optical device (5) and emit a light beam, called the output light beam (F2), to the optical device,- Said optical device being configured to generate a parallel stimulation light beam (F4) of the biological sample (ECH) with a determined constant section, from said output light beam (F2).,

2. System according to claim 1, characterized in that the optical device (5) comprises an optical assembly (50) configured to generate a divergent light beam (F3) from the output light beam (F2) and an off-axis parabolic mirror (51) positioned relative to said optical assembly to reflect said divergent light beam and form said parallel stimulation light beam (F4).

3. System according to claim 2, characterized in that it comprises means for adjusting the position of said optical assembly (50) relative to that of the off-axis parabolic mirror (51).

4. System according to claim 2 or 3, characterized in that it comprises means for adjusting the position of the off-axis parabolic mirror. (51) relative to that of said optical assembly (50).

5. System according to one of claims 2 to 4, characterized in that it comprises means for adjusting the orientation of said optical assembly (50) relative to the off-axis parabolic mirror (51).

6. System according to one of claims 1 to 5, characterized in that it comprises means for adjusting the orientation of the off-axis parabolic mirror (51) relative to said optical assembly (50).

7. System according to one of claims 1 to 6, characterized in that the light source (2) is a regulated laser source.

8. System according to one of claims 1 to 7, characterized in that it comprises a mask arranged at the output of the optical device (5) to shape the section of the parallel stimulation light beam (F4).

9. System according to one of claims 1 to 8, characterized in that the waveguide (4) comprises a separator (40), arranged to separate said input light beam (F1) into said output light beam and a second output light beam, and in that the system comprises a second optical device (5_2) for shaping the second output light beam, configured to generate a second stimulation light beam (F4_2).

10. System according to one of claims 1 to 9, characterized in that the closed enclosure (3) is an incubator.

11. Method for light stimulation of a biological sample, implemented using the system as defined in one of claims 1 to 10, characterized in that it comprises the following steps: - Positioning in said closed enclosure (3) a container (1) in which said biological sample (ECH) to be stimulated is placed, said container (1) comprising an illumination window (10) having an illumination section through which a light beam can penetrate, this light beam being a parallel stimulation light beam (F4) of the biological sample, - Configuring the optical device (5) to obtain the parallel stimulation light beam (F4) with a constant surface section greater than or equal to the illumination section (10) of the illumination window of the container, - Activating said light source (2) to emit the beam input light inside the optical guide (4) and obtain the output light beam to be applied to the optical device for shaping this beam.

12. Method according to claim 11, characterized in that the container (1) is a Petri dish.

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