JP2024507564A - High color rendering white LED virus sterilization element containing 405 nm light and the sterilization lighting device - Google Patents

Abstract

According to the present invention, the light source device that uses a white LED containing 405 nm violet light to exert a sterilizing effect on infectious viruses, etc. uses 400 to 420 nm violet light and white light, which is a visible light wavelength close to the Soret band and Q band absorption of porphyrin. It is a sterilizing lighting device that contains light and can control the intensity of each emission, and provides the effect of inactivating germs such as viruses and bacteria. Unlike UV-C light, which is ultraviolet light, the present invention uses visible light, which is safe for the human body and the ecosystem, and is effective for long-term use.

Description

The present invention relates to a light source device that exhibits a sterilizing effect on infectious viruses and the like using a white LED containing 405 nm violet light.

The infectious disease caused by the new coronavirus (SARS CoV-2, COVID-19) that occurred in Wuhan, China in 2019 is a serious problem worldwide. Even though more than a year has passed since the outbreak, the infection continues to spread. Disinfection, sterilization, and sterilization of new types of infectious viruses are urgent issues not only in medicine but also in public health.

Until now, sterilization using ultraviolet light has used 254 nm ultraviolet light (UV-C) from a low-pressure mercury lamp, which is close to the absorption wavelength of the genes of bacteria such as viruses, and the energy at this wavelength kills the target bacteria by acting directly on the genes. It is believed that However, ultraviolet light around 260 nm is not only harmful to humans, but also destroys inorganic and organic materials. Therefore, it is expected that light will have a sterilizing effect that is safe for the human body and living things.

Recently, Ushio has announced that 222nm far-UVC (excimer gas discharge light) has the effect of inactivating and sterilizing new viruses as light that is safe for the human body, and ultraviolet (UV-C) LED has been developed by a group at Tokushima University. Research results regarding the inactivation effect regarding the new coronavirus have been announced.

In addition to the above research results, it has been reported that 405 nm light is effective against bacteria, Helicobacter pylori, and skin-infecting bacteria (Patent Documents 1 and 2), but white light containing 405 nm violet light There is no report on the effect of inactivating (sterilizing) viruses by irradiation with visible light emitted from LEDs, and there is no invention of a practical device for the same (Non-Patent Document 1). Recently, there is a medical report (Non-Patent Document 2) that many critically ill patients infected with the new coronavirus have excessive ferritin (Fe).

The present invention uses a white LED light source containing 405 nm violet light, which is close to the absorption band of porphyrin, to examine the sterilization mechanism of the new coronavirus through experimental results on a virus similar to the nucleic acid structure (RNA) of the new coronavirus. Concerning the practical application of white LED light sources that exhibit activation and sterilization effects.

1. Patent JP5435619
2. JP2008-25337

E. Kvan and K. Benner, “Mechanistic insights in UV-A mediated bacterial disinfection via endogeneous photosensitizers” J. of Photochemistry & Photobiology, B:Biology 209 (2020) 111899.
W.Liu and H.Li, “Covid-19 attacks the 1-Beta chain of hemoglobin and capture the porphyrin to inhibit human heme metabolism, ChemRxiv 2020, April 10.

The present invention uses a white LED that emits 405 nm violet light, which is close to the absorption range of porphyrins, and uses experimental results regarding a virus similar to the nucleic acid structure (RNA) of the new coronavirus to study the sterilization mechanism. The present invention relates to the practical application of a white LED light source that exhibits inactivation and sterilization effects on bacteria.

According to the present invention, unlike UV-C ultraviolet rays, violet light in the visible light range around 405 nm has the effect of destroying cell membranes and genes through the oxidation effect of active oxygen generated within the cells of target bacteria such as viruses. Express. That is, it is known that many proteins (e.g., porphyrin) that constitute viruses or bind to the aforementioned viruses have absorption wavelengths in the range of 400 to 410 nm (the maximum peak of the SORET band) and 550 to 660 nm (the Q band). ing.

In the present invention, the SORET band and Q band are directly excited using white LED light containing 405 nm violet light, and active oxygen (1O2) having a singlet electron configuration is generated in the living body. The purpose of this invention is to invent a white LED light source that has the effect of killing viruses by attacking and destroying the side chains of viral nucleic acids (DNA or RNA) and cell membranes.

The virus infects humans in the oral cavity, and after combining with saliva, it is dispersed into the air through droplet infection such as when coughing, and then the virus further infects humans and multiplies.

The present invention is a method of sterilizing viruses by simultaneously irradiating 405 nm light and white LED light to droplet infections and virus bound to blood.

To this end, in order to effectively achieve sterilization using 405 nm light, the basis of the invention is a high-output 405 nm light and a white LED light source with a spectral wavelength distribution similar to the absorption spectrum of the Q band.

The present invention is characterized in that a 2-in-1 PKG structure is fabricated in which these structures are simultaneously provided in one package (PKG), and the light output can be varied.

As mentioned above, this invention can effectively inactivate viruses over a long period of time by combining 405 nm violet light, which is effective for sterilizing effects, and controlling the intensity of white light, which has a lighting function.

It does not have an instant sterilization effect like UV-C, but uses visible violet light, so it is effective in safe areas where sterilization is required over a relatively long period of time.

Since it not only has a general lighting function but also has the effect of inactivating (sterilizing) viruses, it can be applied not only to medical institutions such as hospitals and nursing care facilities, but also to a wide range of places such as general homes and commercial facilities.

Figure 1 shows a 2-in-1 PKG structure SMD germicidal lighting device consisting of 405nm violet light and a high color rendering white LED separately excited at 405nm. Figure 2 is a cross-sectional view of the SMD germicidal lighting device, showing how the phosphor is excited and emits light by 405 nm reflected and scattered light. Figure 3 shows the roulette arrangement structure of a 405nm excited high color rendering white LED and a 405nm violet LED COB type germicidal illumination light source, where V indicates the 405nm LED and W indicates the high color rendering white LED. Figure 4 shows the experimental layout of the 15W downlight light source and virus incubator used in the virus and bacteria inactivation experiment. Figure 5 shows a typical example of the emission spectrum (color temperature, 6500K) of a white LED light source for sterilization and a comparison (inset) of the absorption spectrum (Soret band and Q band) of porphyrin. Figure 6 shows survival (inactivation) curves for RVS virus and rotavirus. Figure 7 shows the effect of irradiation on E. coli. (a) Control (non-irradiation) and (b) Irradiation (irradiation) Figure 8 shows the effect of irradiation on Salmonella enterica (S. Typhimurium). (a) schematically shows the state of virus propagation by droplets, and (b) schematically shows the state of the virus bound to porphyrin. Figure 9 shows the virus sterilization mechanism by 405nm light and white light. (a) schematically shows the state of virus propagation by droplets, and (b) schematically shows the state of the virus bound to porphyrin.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and may be embodied in various forms, and these embodiments are intended to provide a complete disclosure of the present invention, and are not limited to the embodiments disclosed below. This is provided to fully illustrate the scope of the invention to those who have the invention. The same reference numerals in the drawings indicate the same elements.

[1] LED light source for sterilization lighting The LED light source used in the present invention has a structure that generates high-output 405 nm violet light and white light with high color rendering properties that is separately excited at 405 nm.

1 and 2 show the light source structure of the LED.

Figure 1 shows a surface mount type (SMD) in which two types of LEDs are mounted on an electrical circuit board. The 405nm LED chip is sealed with silicone resin. On the other hand, high color rendering white has a structure in which phosphor is dispersed and sealed in silicone resin. These two types of LED chips are mounted in one package (PKG).

FIG. 2 is a cross-sectional view of the SMD structure of FIG. 1. The middle wall should be as low as possible to allow the 405nm violet light to be reflected and scattered to the neighboring PKG. That is, even when the high color rendering white LED is not lit, the 405 nm violet light causes the phosphor coated on the high color rendering white LED chip to emit light, so that it can always emit white light.

Furthermore, in order to increase the optical output, we will fabricate a COB structure as shown in Figure 3. As shown in Figures 1 and 2 above, two types of LED chips are placed on a roulette, and the wall between them is kept as low as possible so that the 405nm violet light excites the neighboring phosphors. do.

As described above, the 405 nm violet light has a PKG structure that can always excite the phosphor even when the high color rendering white LED is not lit. Even when an LED light source is attached to a lighting fixture, 405nm light may be reflected from the outer cover and cause the phosphor to emit light.

Below, we will explain about 405nm LED and high color rendering white LED.
(1) 405nm LEDs are composed of semiconductor InGaN quantum well structures in vertical and horizontal chips, and have a light output of 1W or more. The center wavelength is 405 nm, and the emission half width is 15 nm.
(2) High color rendering white LED: Contains the following phosphors excited by 405 nm.
As a blue phosphor, (Sr,Br)10(PO4)6Cl2:Eu
As a green phosphor, SiAlON:Eu
As a yellow phosphor, (Ba,Sr)Si2(O,Cl)2N2:Eu
As the first red phosphor, CaAlSi(ON)2:Eu
As the second red phosphor, CaALSiN2Eu

The above-described phosphor is mixed with silicone resin at a weight ratio of 12.3:1.0:1.0:5.0:0.3. By changing the weight ratio of these phosphors, it is possible to approximate the absorption spectrum of porphyrin shown in FIG. 5, which will be described later. Furthermore, by adjusting the weight ratio of the phosphors, the color temperature can be adjusted from 2000K to 10000K. The average color rendering index (Ra) required for high color rendering lighting characteristics is 90 or higher. Furthermore, by placing LEDs with different color temperatures on the roulette board shown in Figure 3, it is possible to vary the color toning with high output.

[2] Virus sterilization light source and emission spectrum Figure 4 shows the LED sterilization light source used in the test. The light source is equipped with the two types of LEDs shown in FIGS. 1 and 3 above. The structure is airtight to prevent viruses from entering the light source.

The light output was 31μW/cm2 at a distance of 33.5cm from the light source when the power consumption was 15W. Directly below the LED, it is approximately 35mW/cm2. The emission spectrum at this time is shown in Figure 5. The intensity of 405nm is the combined intensity of the light emitted from the violet LED and the 405nm light emitted from the white LED. The wide range of light emission from 430 nm to long wavelength range is the light emission from the phosphor used for white light emission. Color temperature is 6500K. White light has a lighting effect that makes objects easier to see.

[3] Absorption properties of porphyrin The inset of Figure 5 shows the absorption properties of porphyrin.

A sharp peak appears between 350 and 410 nm. This is called the Soret zone. On the other hand, broad absorption is called the Q band (510nm, 545nm, 580nm, 635nm). When compared with the white emission spectrum in Figure 5, it can be seen that the positions of the Soret band and Q band correspond to the emission bands. Furthermore, in the spectrum of the invented sterilizing light source, the emission intensity ratio of 405 nm and white light is relatively close to the intensity ratio of Soret band and Q band. Therefore, it can be seen that the light from the invented high color rendering white LED light source with 405 nm violet excitation is well absorbed by porphyrin.

In the present invention, there are many unknowns as to why the virus can be inactivated (sterilized) with 405 nm purple light, but one hypothesis is that the structure of the coronavirus and the spike (S) protein on the surface Since it contains protein components, it is inferred that Soret band and Q band absorption occurs.

As will be mentioned later in the sterilization mechanism, it is believed that 405nm and white light generate active oxygen within virus cells, which may destroy cell membranes and cleave side chains of DNA and RNA. He made an invention.

Below, experiments related to actual virus inactivation will be explained in detail. The viruses are RSV virus and rotavirus (RVA), which have a similar structure to the new coronavirus. In addition to viruses, we also conducted tests on bacteria. The target bacteria are Escherichia coli and Salmonella enterica, both of which are Gram-negative bacteria.

[4] Virus evaluation test
Inactivation tests were conducted at the Korea Testing and Research Institute (KTR) for two types of infectious viruses, RSV (Human respiratory syncytial virus) and RVA (Rotavirus A).

1. Culture of host cells Host cells were cultured using cell culture medium under conditions of 5% CO2 and a temperature of 36±2°C.

2. Virus culture
2.1 Cultivation of RSV After washing Hep-2 cells cultured in a monolayer in a flask with PBS, 3 ml of a diluted RSV solution was inoculated. After virus infection for 60 to 90 minutes, virus culture medium was added and the virus was cultured for 3 to 12 days until more than 90% of the host cells exhibited cytopathic effect (CPE). Thereafter, the culture supernatant liquid was centrifuged at 2000 rpm for 10 minutes, and the supernatant liquid was filtered through a 0.45 μm filter to separate the virus.

2.2 Cultivation of RVA After washing CV-1 cells cultured in a monolayer in a flask with PBS, 3 ml of RVA dilution was inoculated. After infection with the virus for 60-90 minutes, virus culture medium was added and the virus was cultured for about 1 week until more than 90% of the host cells developed cell lesion phenomenon (CPE). Thereafter, the culture supernatant liquid was centrifuged at 2000 rpm, and the supernatant liquid was filtered through a 0.45 μm filter to separate the virus.

3． antiviral test
3.1 Cytotoxicity Test After injecting 0.2 ml of the test virus into a sterilized petri dish, it was dried for 30 minutes under laminar flow standby conditions inside the sterile test stand to form a virus film. This was placed at a distance of 30 cm from the light source, and measurements were taken while varying the irradiation time. After adding 2 ml of virus culture medium to the petri dish, the film was collected by scraping off the surface using a cell scraper. It was serially diluted 10 times in virus culture medium and treated with host cells at (36±2)°C for 1 hour, after which the cytotoxicity was observed under a microscope.

3.2 Blast Toxicity Test After treating host cells with the solution collected in the cytotoxicity test for 30 minutes, the cell monolayer was washed with PBS and then inoculated with a diluted test virus. Thereafter, they were infected with the virus and cultured.

3.3 Neutralization test The solution collected in the cytotoxicity test and the diluted test virus were mixed in equal amounts, allowed to react for about 20 minutes, and then ingested into host cells. Thereafter, they were infected with the virus and cultured.

3.4 Cell culture target group Host cells were treated with virus culture medium and used as the target for cell culture.

3.5 Virus Target Group The test virus was mixed in the virus culture medium at a ratio of 1:9 and serially diluted 10 times in the virus culture medium. Each dilution was inoculated into host cells and the titer of the test virus was determined.

That is, after adding 2 ml of virus culture medium to the virus film, the virus was collected by scraping off the surface using a cell scraper, and then diluted stepwise in 10-fold increments in the virus culture medium. Each dilution was inoculated into host cells, and the virus titer in the control group was measured. After the virus film was left at 22±2°C for 2 and 4 hours, 2 ml of virus culture medium was added and the virus titer was measured.

3.6 Virus test group After forming a virus film, the virus titer was measured in the same manner as above.

3.7 Virus Recovery 100 μl of the diluted solution for each stage was applied to 4 wells (repeated 4 times) of cells prepared in advance in a 96 well plate, and cultured under the conditions shown in Table 1.

3.8 Staining conditions
Cells were treated with a staining reagent of 25% methyl alcohol and 0.5% crystal violet, and stained at 22±2°C for 10 minutes.

3.9 Observation and evaluation
The wells stained with Crystal violet were counted, and the titer was calculated using the Spearman-Karber method.

Example 1

4 Test results
4.1 Cytotoxicity Test and Blast Toxicity Test As a result of confirming the cytotoxicity of the test solution, no cytotoxicity was observed for either Hep-2 or CV-1 cells. Furthermore, no blast toxicity was observed in the test solution, confirming the neutralization of the sample in the neutralization target. These results are shown in Table 2 for RSV and RVA.

Table 2 below shows the blast toxicity test swim neutralization test (+: indicates viral infection)

4.2 Antiviral test results
4.2.1 RSV
The titer of the test virus is 107.00TCID50/100μL, the titer of the initial target group is 106.80TCID50/carrier, the titer of the target group after 2 hours is 106.30TCID50/carrier, the titer of the target group after 4 hours is 105.55TCID50 /carrier, and the titer of the test group after 2 hours was observed to be 105.30TCID50/carrier, and the titer of the control group after 4 hours was observed to be 102.80TCID50/carrier. Therefore, the log phenomenon was 1.00 after 2 hours and 2.75 after 4 hours. These values mean that the virus was inactivated by 90% and 99.9%, respectively.

4.2.2 RVA
Similarly, for RVA, the log phenomenon was calculated to be 1.50 after 2 hours and 2.50 after 4 hours.

These values mean that the virus inactivation rate was 90% and 99.9%, respectively.

The experiment was conducted using a light source installed in the incubation apparatus as shown in Figure 4. Power was supplied from the outside and the light output was monitored using a sensor.

Figure 6 shows the evaluation results regarding inactivation. The vertical axis shows the virus survival rate, and the horizontal axis shows the cumulative irradiation time. It can be seen that approximately 99.9% of both viruses are killed after about 4 hours. The horizontal axis is expressed as the product of radiation density (Φ=W/cm2) x irradiation time (t). In other words, increasing Φ means that the irradiation time can be shortened. For example, for 6 minutes of irradiation, 100Φ is sufficient. Although 405 nm light is visible light, the limit value (exempt: 10 W/m2) of near ultraviolet ray (UV-A) irradiation amount for eye safety is specified in IEC62471. With this LED light source, it was 0.31W/m2.

Example 2

5 Sterilization experiments involving bacteria Sterilization experiments involving Escherichia coli and Salmonella were also conducted at KTR. Figure 7 shows the experimental results for E. coli. Figure 8 shows the experimental results regarding Salmonella. The survival rate was evaluated by counting the number of colonies on each plate (Petri dish) in the Control and Irradiation comparison plots.

E. coli was about 4% after 4 hours. On the other hand, about 10% of Salmonella bacteria was present after 4 hours. According to Patent Document 1, S.augus and B.cereus are 100% inactivated when irradiated with an intensity of 8μW/cm2 for 24 hours at a distance of 20cm. However, it has been reported that about 10% of E. coli remains even after 24 hours. The LED light source of the present invention has a radiation intensity of 31 μW/cm2 at a height of 33.5 cm, which is about four times stronger than the light source of Patent Document 1. Therefore, it is thought that white light also worked effectively, and results similar to those obtained in 24 hours were obtained in about 4 hours. This result also confirmed the effectiveness of the light source of the present invention in killing bacteria.

A comparison with Example 1 shows that viruses can be inactivated with a lower irradiation dose than bacteria. Therefore, it is expected that irradiation with 405 nm light will cause a different inactivation mechanism between viruses and bacteria such as bacteria. At present, the mechanism of why viruses are inactivated by 405 nm violet light has not been elucidated biologically or medically, but the possible mechanisms will be discussed below.

6 Proposal for sterilization mechanism Viruses are particles with a size of several tens to hundreds of nanometers, and consist of a membrane called Kapton and a membrane containing genes (DNA, RNA). Furthermore, it has a spike (S) protein and a membrane called an envelope that covers its outside. Viruses have limited information and cannot reproduce on their own. Instead, they invade other cells, infiltrate their genes, and use the enzymes (proteins) of those cells to reproduce themselves. Proliferate. In the present invention, we believe that 405 nm light may be effective against this enzyme.

According to Non-Patent Document 2, it has been reported that the new coronavirus infection causes not a medical lung disease but a red blood cell disease. In other words, it was revealed that the virus attacks hemoglobin in red blood cells through a series of cellular actions, and as a result, makes it impossible for red blood cells to carry oxygen. Viruses also require large amounts of the nutrient porphyrin to survive. Most of the porphyrins in the human body are heme combined with Fe. Therefore, it is thought that the virus targets hemoglobin and attacks heme to acquire porphyrin. This polyphyllene is a substance that has light absorption in the SORERT band and Q band as explained in FIG. 5 of the present invention. When this is irradiated with white light containing 405nm violet light, it strongly absorbs 405nm violet light and visible light, generating singlet active oxygen (1O2), a radical species, which binds to the cell membrane and RNA of the virus. It destroys. The outline is shown in Figures 9(a) and (b).

It is thought that the cell membrane and RNA of the virus are destroyed and inactivated by the mechanism described above.

Figure 9(a) shows how the new coronavirus is transmitted mainly through droplet infection, with the virus scattering in the air. This virus is assumed to be in a state in which it binds to, for example, periodontal disease bacteria (P. gingivalis) containing a large amount of porphyrin and blood in the oral cavity. Therefore, as explained above, by irradiating 405nm light to a virus that is bound in a state that is rich in porphyrin, it is possible to inactivate viruses scattered in the air with the same effect as described above. It is assumed that

Figure 9(b) shows that the virus cell membrane and RNA side chain are destroyed by the effect of active oxygen (singlet oxygen: 1O2) generated by 405 nm irradiation, which is assumed to occur when blood and virus combine. Shown schematically.

The above description is merely an illustrative explanation of the technical idea of the present invention, and a person with ordinary knowledge in the technical field to which the present invention pertains will be able to understand the technical idea within the scope of the essential characteristics of the present invention. It is believed that various modifications and variations are possible. Therefore, the examples disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain it, and the scope of the technical idea of the present invention is limited by such examples. It's not a thing. The protection scope of the present invention should be interpreted in accordance with the following claims, and all technical ideas within the scope equivalent thereto should be construed as falling within the scope of rights of the present invention.

Claims (4)

It includes an LED light source structure consisting of two types of light emitting elements: a 400-410nm violet LED and a high color rendering white LED that is separately excited at a wavelength of 405nm, and has an emission spectrum distribution close to the light absorption band of porphyrin. A sterilizing lighting device effective for inactivating viruses and bacteria with a light radiation intensity of 3.1μW/cm2 or higher. In paragraph 1,
Even when the high color rendering white LED is not lit, the phosphor coated on the surface of the high color rendering white LED emits light with violet light of 400 to 410 nm, and the emission spectrum has a distribution over 500 to 700 nm. , a sterilizing lighting device with lighting characteristics of a color rendering index of 90 or more and a luminous flux of 1000 lm or more. In paragraph 2,
The white LED contains CaAlSiN2:Eu or CaAlSiN:Eu as a red phosphor, BaSr(O,Cl)N:Eu as a yellow phosphor, SiAlON:Eu as a green phosphor, and a blue phosphor. Germicidal lighting device containing (Sr,Br)10(PO4)6Cl2:Eu as a body In paragraph 1,
The color temperature of the white LED light source is 2000K or more and less than 10000K, and the sterilization lighting device is capable of adjusting the color between two LEDs with different color temperatures.