SK288148B6 - Light source with luminous field homogeneity, especially for inducing and monitoring photodynamic phenomenon in vitro - Google Patents

Abstract

Light source with luminous field homogeneity, especially for inducing and monitoring photodynamic phenomenon in vitro, wherein said light source comprises a body (1) adapted to place therein a bed (3) of a specimen to be analyzed and including a set of LEDs (5), wherein said LEDs (5) are disposed within the body (1) and are arranged in the form of a circle along the periphery of the bed (3), and namely in at least one horizontal plane, whereby they are directed toward the center skew downwards into the region (O) to be analyzed.

Description

Technical field

The invention relates to an arrangement of a light source with a light field homogeneity, in particular for inducing and monitoring an in vitro photodynamic phenomenon, intended in particular for the treatment of cancer by photodynamic therapy.

BACKGROUND OF THE INVENTION

Photodynamic therapy (PDT) is another option for cancer treatment in addition to chemotherapy, radiotherapy and immunotherapy. It is a photochemotherapy which represents the combined use of a photodynamic active substance, i. j. sensitizer and light in the presence of oxygen. The principle of this tumor treatment is based on the total or external administration of a photodynamic active substance followed by irradiation with ultraviolet rays (UVA) or visible radiation, i. j. light. The photosensitizing substance selectively accumulates in the tumor after a period of time, and then irradiation with light of a suitable wavelength is performed, consistent with the absorption maximum of the sensitizer. The physical essence of photodynamic therapy is the transfer of energy or electron from an excited sensitizer molecule to an oxygen molecule or other substrate accompanied by the formation of reactive oxygen species or free radicals. The lifetime of these products in the cellular environment is very short, since they react very quickly with the surrounding biomolecules. Depending on the size of the induced changes in their molecular structure and thus the degree of cellular damage, several cellular processes leading to cell death may be initiated.

In the preclinical research phase, various tumor and non-tumor cell cultures, for example grown on petri dishes, are used to study the effectiveness of this type of therapy. Laser or diode light is the most commonly used light source to activate the sensitizer. An optical diffuser is often placed between the laser beam and the object to create a wider radiation surface. From the light coming from the LEDs, an illumination field is achieved by varying the arrangement of several LEDs, producing different degrees of luminous flux homogeneity for both in vivo and in vivo applications, as described, for example, in KR20090055891, EP2044974, US2009088824, CN101214403, US200722077833 , WO2005035058, WO9321842, as well as for in vitro applications, as shown in DE102008008875, CZ 2006-813 A1 or WO9321842. The arrangement of the diodes in the irradiators is either random or in rows of equal or different spacing.

A suitable arrangement of diodes associated with the formation of a homogeneous light field is solved only in a few publications, for example in WO2005035058 or CZ 2006-813 A1, which solve the problem of homogeneity in irradiation from above. The LEDs in these solutions are arranged in a hexagonal shape, where they are fixed at a constant distance from each other on a mat above the storage. Sample analysis is typically performed by detecting a signal using a detection device located above or below the sample. A disadvantage of these solutions is that the analysis of the resulting effect of photodynamic therapy in vitro, i. j. determination of the total amount of oxidized substance can be carried out after a certain period of irradiation. Indeed, a widely used and popular detector is a chemical label which, upon penetration into cells and its oxidation, is converted into a fluorescent product, the overall yield of which can be readily determined using commercially available fluorescent spectrophotometers or readers. Because of the rapid photophysical-chemical changes associated with the formation of reactive oxygen species and the self-photo-oxidation of the detection tag itself, it is desirable that measurements take place continuously over time.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a light source that is structurally relatively simple to provide light with uniform luminous flux while allowing continuous monitoring of photodynamic phenomenon products using commercially available spectrophotometers or readers.

SUMMARY OF THE INVENTION

The objective set is largely achieved by the invention, which is a light source with a uniformity of the light field, in particular for inducing and monitoring the in vitro photodynamic phenomenon, consisting of a body adapted to accommodate the repository of the sample to be analyzed and comprising a LED set. The essence of the solution is that the LEDs are mounted in the body in a circle around the perimeter of the repository in at least one horizontal plane, and are directed centered downwards into the analyzed area (O).

In a preferred embodiment, the LEDs are removably mounted in the body, and a circular recess is formed in the central portion of the body, the bottom of which has a through hole with circumferential shoulder to accommodate the sample sample storage.

SK 288148 Β6

Ideally, the LEDs are distributed around the recess periphery and connected in parallel, with the connection wires of their sockets extending laterally outside the body.

The main advantage of the new design of the light source is that it allows continuous monitoring of products resulting from photodynamic phenomena. Another advantage is that the LEDs are easily removable and that only by sliding and sliding it can easily be replaced with other LEDs with different radiation characteristics. The considerable advantages of the device are its low purchase price, small dimensions and minimum energy consumption of operation.

BRIEF DESCRIPTION OF THE DRAWINGS

A specific example of a light source design is illustrated by the accompanying drawings, in which:

Fig. 1 is a top view of the light source, FIG. 2 is a vertical axial section of the light source of FIG. 1, FIG. 3 is a diagram of the electrical wiring of LEDs; FIG. 4 is a top view of the light source showing the distribution of the areas analyzed, FIG. 5 is a diagram for calculating the minimum horizontal emitting angles (γ) of LEDs to achieve maximum light field homogeneity for a selected area of interest.

DETAILED DESCRIPTION OF THE INVENTION

The light source according to the invention is in the basic embodiment of FIG. 1 and FIG. 2 is formed by a plate-shaped body I, preferably of a rectangular shape, in the central part of which a circular recess 2 is formed, the bottom 21 of which is provided with a through hole 22 with circumferential shoulder 23 to accommodate the sample sample storage 3, for example a petri dish. In the side walls 24 of the recess 2, the base 4 with LEDs 5 are directed downwardly in the center. The sockets 4 and the LEDs 5 are regularly distributed around the periphery of the recess 2 and are connected in parallel as shown in FIG. 3, wherein the connecting conductors 41, their sockets 4 are led out laterally outside the body L

In order to achieve a uniform incidence of light from the array of LEDs 5 on the selected sensed analyzed area O with the diameter g shown in FIG. 4, the minimum horizontal beam angle γ, the magnitude of which is calculated from the formula:

γ = 2 x arctg g / 2 ^{, 2} + s ² and for the calculation of the minimum vertical beam angle g, the formula shall be:

s ² + r (r = g) / 4 and = 2 x arccos

In (I72) ² + a ² (R G) ^2/4 wherein: g / 2 - is the radius of the analyte in O, r / 2 - is the distance between the top of the radiating cone of the LED 5 to the level of analyte in O and the center of the area , s - is the distance between the apex of the emitting cone of LED 5 from its projection to the plane of the area to be analyzed.

The explanatory diagrams for calculating the minimum emitting angles α, γ of the LEDs 5 in the vertical and horizontal directions are further illustrated in FIG. 2 and FIG. 5th

The efficiency and functionality of the light source has been tested for currently commercially produced high-intensity LEDs 5 with a diameter of 3 and 5 mm, with emitting angles ranging from 15 ° to 175 ° and emitting radiation in the wavelength range 300 - 1100 nm. To arrange the diode array 24 of FIG. 1 with a radiating peak at a distance r / 2 = 25 mm from the center of the sampled area O, a homogeneous irradiated area was created on the detection area O with a diameter of g = 19.6 mm containing four circular areas with a diameter m = 6.8 mm. set up the analyzer to read from 96-well plate assays. For the angle of illumination of LEDs 5 in the vertical direction, the optimum angle value was at least γ = 42.2 and for the angle of illumination in the horizontal direction at least α = 12.6 °.

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In order to achieve homogeneous illumination of a larger sample area, for example with a diameter of 35 mm for Petri dishes, it was necessary to select LEDs 5 with a minimum beam angle γ = 87.2 °.

Depending on the sensitizer used, different LEDs 5 differing in the wavelength spectrum as described in CZ 2006-813 A1 can then be used to induce photodynamic phenomena in cells.

The described embodiment is not the only possible solution according to the invention, because without affecting its nature, the actual construction of the body 1 can be solved in a different way and different number of LEDs 5 can be used according to the size of the sampled area O. they can be placed in several rows above each other in the larger plane analyzed, and in order to achieve greater light intensity.

Industrial usability

The light source of the invention can be used to monitor photodynamic changes by in vitro methods, in particular for photodynamic therapy, which is used to destroy tumor cells by singlet oxygen and other radicals formed in tumor tissue after irradiation with light.

Claims (4)

PATENT CLAIMS A light source having a uniformity of light field, in particular for inducing and monitoring an in vitro photodynamic phenomenon, comprising a body (1) adapted to receive a sample storage site (3) and comprising a set of LEDs (5), characterized in that the LEDs ( 5) are mounted in the body (1) in a circle around the circumference of the bearing (3) in at least one horizontal plane, being directed at an angle downwards to the analyzed area (O). Light source according to claim 1, characterized in that the LEDs (5) are removable in the body (1). Light source according to claims 1 and 2, characterized in that a circular recess (2) is formed in the central part of the body (1), the bottom (21) of which has a through hole (22) with a circumferential shoulder (23) for accommodating the receptacle (1). 3) of the sample to be analyzed, wherein the sockets (4) for mounting the LEDs (5) are mounted in the side walls (24) of the recess (2). Light source according to claim 3, characterized in that the LEDs (5) are distributed around the periphery of the recess (2) and connected in parallel, the connecting wires (41) of their sockets (4) being led laterally out of the body.