Integrating Cavity UVC Irradiation for Rapid Pathogen Inactivation
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Solution Overview
Problem
Existing UV disinfection methods, such as UV lamps and pulsed Vis-NIR lasers, are inefficient and require high power and long irradiation times, making them unsuitable for rapid viral inactivation in air conditioning systems and other environments where air passage is brief.
Innovation Solution
A device incorporating a pulsed nanosecond 266 nm UV laser coupled with an integrating cavity (IC) having Lambertian reflective walls, primarily made of polytetrafluoroethylene, to enhance viral inactivation efficiency by diffusely scattering light within a confined volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If UV lamps or pulsed Vis-NIR lasers are used for viral inactivation, then the method is non-contact and can be applied to surfaces, air, and water, but the inactivation efficiency is low requiring high power and long irradiation times
Solution Approach 1:
The patent employs pulsed UV laser irradiation with specific pulse durations (nanosecond to picosecond range) and repetition rates to achieve efficient viral inactivation. The periodic pulsing allows the laser to deliver high peak power for effective DNA damage while maintaining lower average power for heat management, resolving the contradiction between inactivation efficiency and irradiation time.
Solution Approach 2:
The patent optimizes multiple parameters including laser wavelength (266 nm for maximum nucleic acid absorption), pulse duration, repetition rate, and irradiation dose to achieve rapid inactivation. By changing these parameters, the system achieves high inactivation efficiency within short times while avoiding excessive heat accumulation.
2Speed
If high power UV irradiation is applied to achieve rapid inactivation, then inactivation speed increases, but heat losses to environment increase requiring additional cooling efforts
Solution Approach 1:
Pulsed laser operation allows high peak power for rapid inactivation during the pulse, followed by off-periods that prevent continuous heat accumulation. The duty cycle can be adjusted to maintain inactivation speed while controlling average power and associated heat losses, eliminating the need for additional cooling systems.
Solution Approach 2:
The patent uses UV laser light (266 nm) which is absorbed by nucleic acids to directly damage viral DNA, creating a photoproduct state that inactivates the virus. This direct photchemical mechanism avoids the need for high thermal energy, achieving rapid inactivation without significant heat losses to the environment.
3Ease of operation
If conventional UV lamps are used, then the method is simple and non-contact, but the inactivation requires large doses and is time-consuming
Solution Approach 1:
The patent replaces conventional UV lamps with a pulsed UV laser system. The laser provides coherent, high-intensity light that can be focused and delivered with precise temporal control, achieving much higher inactivation rates while maintaining the non-contact simplicity of the method. The laser's ability to deliver energy in concentrated pulses maintains operational simplicity while dramatically improving productivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The integrating cavity device achieves viral inactivation rates at least an order of magnitude higher than direct UV exposure, reducing inactivation times from seconds to milliseconds, effectively inactivating pathogens like SARS-CoV-2 and other respiratory viruses.
Implementation Method 1
The wall is preferably characterized by Lambertian reflectance at a wavelength of the UVC light
Implementation Method 2
UVC light causing damage by inducing photochemical fusion of two adjacent pyrimidines into covalently linked dimers, RNA-protein cross-linking, and site-specific molecular damage
Implementation Method 3
The maximum absorption of nucleic acids is at about 265 nm
Implementation Method 4
A source of laser light configured to generate and deliver a UVC light into this volume through the aperture
Implementation Method 5
impulsive stimulated Raman scattering resulting in aggregation of viral capsid proteins was the main inactivation mechanism
Data Source
AI summary
Methodology for increasing efficiency of a pathogen inactivation via enhancing UVC light absorption at such pathogen by multiple diffuse scattering of the light at a wall defining a substantially closed volume, thereby increasing a number of angles at which the pathogen is being irradiate as compared with a direct irradiation of the pathogen with a beam of such light.