Photoeradication of microorganisms with pulsed purple or blue light

Abstract

The present invention is directed to a system and method for photoeradication of microorganisms from a target. The method includes the step of obtaining test data for a plurality of experiments each of which comprises irradiating test microorganisms with a plurality of light pulses having a wavelength that ranges from 380 nm to 500 nm. The light pulses have a plurality of pulse parameters (peak irradiance, pulse duration, and off time between adjacent light pulses) and are provided at a radiant exposure that ranges from 0.5 J/cm2 to 60 J/cm2 during each of a plurality of irradiation sessions. The test data comprises a survival rate for the test microorganisms after irradiation with the light pulses. The method also includes the step of analyzing the test data to identify the pulse parameters for the light pulses and the radiant exposure for each of the irradiation sessions that result in a desired survival rate for the test microorganisms. The method further includes the step of irradiating the microorganisms of the target with light pulses having the identified pulse parameters at the identified radiant exposure for each of the irradiation sessions so as to photoeradicate all or a portion of the microorganisms.

What is claimed and desired to be secured by Letters Patent is as follows: 
     
         1 . A lighting system for sanitization of a surface located within an environment contaminated with microorganisms, comprising:
 a light source configured to generate purple or blue light having a wavelength that ranges from 380 nm to 500 nm; and   an electronic circuit configured to control the light source so that the pulsed purple or blue light is applied in a pulsed mode of irradiation to provide a plurality of light pulses in which (a) the light pulses have a peak irradiance and a pulse duration sufficient to optically excite a photoactive molecule capable of photoeradication of the microorganisms and (b) the light pulses are separated by an off time sufficient to allow the photoactive molecule to return to a ground state creating an oxidation reaction that produces free radicals which destroy a cellular structure of the microorganisms to thereby cause photoeradication of all or a portion of the microorganisms on the surface.   
     
     
         2 . The lighting system of  claim 1 , wherein the light source is configured to directly illuminate the surface with the purple or blue light. 
     
     
         3 . The lighting system of  claim 1 , further comprising an optical element configured to redirect the purple or blue light from the light source to the surface. 
     
     
         4 . The lighting system of  claim 3 , wherein the optical element comprises a diffuser configured to evenly distribute the purple or blue light across the surface. 
     
     
         5 . The lighting system of  claim 1 , wherein the light source comprises one of lasers, light emitting diodes (LEDs), organic light emitting diodes (OLEDs), printed light emitting diodes (printed LEDs), polymer light emitting diodes (PLEDs), quantum dot light emitting diodes (QDLEDs), and fluorescent tubes. 
     
     
         6 . The lighting system of  claim 1 , wherein the peak irradiance of the light pulses at the surface ranges from 0.3 mW/cm 2  to 60 mW/cm 2 , the pulse duration of the light pulses ranges from 5 microseconds to 1,000 microseconds, and the off time between the light pulses ranges from 10 microseconds to 1 second. 
     
     
         7 . The lighting system of  claim 1 , wherein the light pulses are provided at a duty factor that ranges from 20% to 33% and a pulse repetition rate that ranges from 33 kHz to 40 kHz. 
     
     
         8 . The lighting system of  claim 1 , wherein the light source is further configured to generate white light, and wherein the electronic circuit is configured to control the light source so that the white light is applied in a continuous wave mode of irradiation to thereby provide lighting within the environment. 
     
     
         9 . The lighting system of  claim 8 , wherein the electronic circuit is configured to control the light source so that the white light has a color temperature in the range of 1700 kelvins (K) to 9500 kelvins (K). 
     
     
         10 . The lighting system of  claim 8 , wherein the electronic circuit is configured to control the light source so that the white light is applied either simultaneously or sequentially with the pulsed purple or blue light. 
     
     
         11 . The lighting system of  claim 1 , wherein the microorganisms comprise an aerobic or anaerobic bacteria (Gram positive and Gram negative). 
     
     
         12 . The lighting system of  claim 11 , wherein the microorganisms comprise one of methicillin-resistant  Staphylococcus aureus  (MRSA),  Salmonella  spp.,  E. coli , and  Listeria  spp. 
     
     
         13 . The lighting system of  claim 1 , wherein the microorganisms comprise a virus. 
     
     
         14 . The lighting system of  claim 13 , wherein the microorganisms comprise one of SARS-CoV, 2019-nCoV, human coronavirus 229E, bat coronavirus HKU9-1, H1N1, norovirus (NoV), feline calicivirus, influenza virus type A, HCoV-OC43, and HCoV-NL63. 
     
     
         15 . The lighting system of  claim 1 , wherein the microorganisms comprise a fungus. 
     
     
         16 . The lighting system of  claim 1 , wherein the environment comprises one of a locker room, a restroom, an airplane, a school, a beach, a playground, a playing field, a hospital, and a clinical environment. 
     
     
         17 . A lighting system for photoeradication of microorganisms from a surface, comprising:
 a light source configured to generate purple or blue light having a wavelength that ranges from 380 nm to 500 nm; and   an electronic circuit configured to control the light source so that the purple or blue light is applied in a pulsed mode of irradiation to thereby cause photoeradication of all or a portion of the microorganisms on the surface.   
     
     
         18 . The lighting system of  claim 17 , wherein the light source is configured to directly illuminate the surface with the purple or blue light. 
     
     
         19 . The lighting system of  claim 17 , further comprising an optical element configured to redirect the purple or blue light from the light source to the surface. 
     
     
         20 . The lighting system of  claim 19 , wherein the optical element comprises a diffuser configured to evenly distribute the purple or blue light across the surface. 
     
     
         21 . The lighting system of  claim 17 , wherein the light source comprises one of lasers, light emitting diodes (LEDs), organic light emitting diodes (OLEDs), printed light emitting diodes (printed LEDs), polymer light emitting diodes (PLEDs), quantum dot light emitting diodes (QDLEDs), and fluorescent tubes. 
     
     
         22 . The lighting system of  claim 17 , wherein the purple or blue light comprises a plurality of light pulses in which (a) the light pulses have a peak irradiance and a pulse duration sufficient to optically excite a photoactive molecule capable of photoeradication of the microorganisms and (b) the light pulses are separated by an off time sufficient to allow the photoactive molecule to return to a ground state creating an oxidation reaction that produces free radicals which destroy a cellular structure of the microorganisms to thereby cause photoeradication of all or a portion of the microorganisms. 
     
     
         23 . The lighting system of  claim 17 , wherein the purple or blue light comprises a plurality of light pulses that destroy the RNA or DNA genomes of all or a portion of the microorganisms. 
     
     
         24 . The lighting system of  claim 17 , wherein the purple or blue light comprises a plurality of light pulses in which the peak irradiance of the light pulses at the surface ranges from 0.3 mW/cm 2  to 60 mW/cm 2 , the pulse duration of the light pulses ranges from 5 microseconds to 1,000 microseconds, and the off time between the light pulses ranges from 10 microseconds to 1 second. 
     
     
         25 . The lighting system of  claim 17 , wherein the purple or blue light comprises a plurality of light pulses provided at a duty factor that ranges from 20% to 33% and a pulse repetition rate that ranges from 33 kHz to 40 kHz. 
     
     
         26 . The lighting system of  claim 17 , wherein the light source is further configured to generate white light, and wherein the electronic circuit is configured to control the light source so that the white light is applied in a continuous wave mode of irradiation. 
     
     
         27 . The lighting system of  claim 26 , wherein the electronic circuit is configured to control the light source so that the white light has a color temperature in the range of 1700 kelvins (K) to 9500 kelvins (K). 
     
     
         28 . The lighting system of  claim 26 , wherein the electronic circuit is configured to control the light source so that the white light is applied either simultaneously or sequentially with the pulsed purple or blue light. 
     
     
         29 . The lighting system of  claim 17 , wherein the microorganisms comprise an aerobic or anaerobic bacteria (Gram positive and Gram negative). 
     
     
         30 . The lighting system of  claim 29 , wherein the microorganisms comprise one of methicillin-resistant  Staphylococcus aureus  (MRSA),  Salmonella  spp.,  E. coli , and  Listeria  spp. 
     
     
         31 . The lighting system of  claim 17 , wherein the microorganisms comprise a virus. 
     
     
         32 . The lighting system of  claim 31 , wherein the microorganisms comprise one of SARS-CoV, 2019-nCoV, human coronavirus 229E, bat coronavirus HKU9-1, H1N1, norovirus (NoV), feline calicivirus, influenza virus type A, HCoV-OC43, and HCoV-NL63. 
     
     
         33 . The lighting system of  claim 17 , wherein the microorganisms comprise a fungus. 
     
     
         34 . The lighting system of  claim 17 , wherein the surface is located within an environment contaminated with the microorganisms. 
     
     
         35 . The lighting system of  claim 34 , wherein the environment comprises one of a locker room, a restroom, an airplane, a school, a beach, a playground, a playing field, a hospital, and a clinical environment. 
     
     
         36 . Alighting system for photoeradication of microorganisms from a surface located within an environment, comprising:
 a light source configured to generate purple or blue light and white light; and   an electronic circuit configured to control the light source so that (a) the purple or blue light is applied in a pulsed mode of irradiation to thereby cause photoeradication of all or a portion of the microorganisms on the surface and (b) the white light is applied in a continuous wave mode of irradiation to thereby providing lighting within the environment.   
     
     
         37 . The lighting system of  claim 36 , wherein the electronic circuit is configured to control the light source so that the white light has a color temperature in the range of 1700 kelvins (K) to 9500 kelvins (K). 
     
     
         38 . The lighting system of  claim 36 , wherein the electronic circuit is configured to control the light source so that the white light is applied either simultaneously or sequentially with the pulsed purple or blue light.