Photoeradication of microorganisms with pulsed purple or blue light
First Claim
1. A method for photoeradication of microorganisms from a target, the method comprising:
- obtaining test data for each of a plurality of experiments, wherein each experiment comprises irradiating test microorganisms with a sequence of light pulses having a plurality of pulse parameters and a wavelength that ranges from 380 nm to 500 nm, wherein the pulse parameters comprise a peak irradiance for each of the light pulses, a pulse duration for each of the light pulses, and an off time between each two adjacent light pulses, and wherein the test data comprises a survival rate for the test microorganisms after irradiation with the light pulses;
analyzing the test data to identify the pulse parameters that result in a survival rate for the test microorganisms of between 0% and 50%; and
irradiating the microorganisms of the target with the light pulses having the identified pulse parameters in accordance with an irradiation schedule.
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Abstract
The present invention is directed to a system and method for photoeradication of microorganisms from a target. A light source is configured to irradiate the target with purple or blue light in a pulsed mode of irradiation at an average irradiance that preferably ranges from 0.1 mW/cm2 to 20 mW/cm2. An electronic circuit is configured to control the light source in accordance with an irradiation schedule that includes a plurality of irradiation sessions. The light source is controlled to provide the purple or blue light at a radiant exposure that preferably ranges from 0.5 J/cm2 to 60 J/cm2 during each of the irradiation sessions. The irradiation sessions are provided at a plurality of time intervals so as to cause photoeradication of all or a portion of the microorganisms.
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Citations
28 Claims
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1. A method for photoeradication of microorganisms from a target, the method comprising:
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obtaining test data for each of a plurality of experiments, wherein each experiment comprises irradiating test microorganisms with a sequence of light pulses having a plurality of pulse parameters and a wavelength that ranges from 380 nm to 500 nm, wherein the pulse parameters comprise a peak irradiance for each of the light pulses, a pulse duration for each of the light pulses, and an off time between each two adjacent light pulses, and wherein the test data comprises a survival rate for the test microorganisms after irradiation with the light pulses; analyzing the test data to identify the pulse parameters that result in a survival rate for the test microorganisms of between 0% and 50%; and irradiating the microorganisms of the target with the light pulses having the identified pulse parameters in accordance with an irradiation schedule. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 25, 26)
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9. A method for photoeradication of microorganisms from a target, the method comprising:
irradiating the target with purple or blue light in a pulsed mode of irradiation during each of a plurality of irradiation sessions, wherein the light comprises a plurality of light pulses each of which excites a photoactive molecule present in the microorganisms and wherein an off time between the light pulses enables return of the photoactive molecule to a ground state to thereby create an oxidation reaction that produces free radicals which destroy a cellular structure of the microorganisms, wherein the light pulses are provided at a dose controlled by feedback from a photo sensor during each of the irradiation sessions, wherein the photo sensor detects light emitted by the photoactive molecule during irradiation of the microorganisms, wherein each of the irradiation sessions is terminated when the detected light reaches a predetermined lower level, and wherein the microorganisms are intermittently irradiated to determine when the detected light returns to a predetermined upper level upon which a next of the irradiation sessions is initiated. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A method for photoeradication of microorganisms from a target, the method comprising:
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determining a plurality of pulse parameters for a sequence of light pulses having a wavelength that ranges from 380 nm to 500 nm, wherein the pulse parameters comprise (a) a peak irradiance and a pulse duration for each of the light pulses that are selected to enable excitation of a photoactive molecule present in the microorganisms and (b) an off time between each two adjacent light pulses that is selected to enable return of the photoactive molecule to a ground state to thereby create an oxidation reaction that produces free radicals which destroy a cellular structure of the microorganisms; determining an irradiation schedule for application of the light pulses having the pulse parameters during each of a plurality of irradiation sessions separated by one or more recovery periods, wherein the irradiation sessions are timed to target the microorganisms at a specified time during a replication cycle of the microorganisms; and irradiating the microorganisms of the target with the light pulses having the pulse parameters in accordance with the irradiation schedule. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 27, 28)
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Specification