Visible Light Bacterial Inactivation Without Photosensitizers
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Solution Overview
Problem
Current methods for inactivating medically important Gram-positive bacteria like MRSA, Staphylococcus, Streptococcus, Enterococcus, and Clostridium species are limited by the need for photosensitizing agents, which is a significant practical disadvantage.
Innovation Solution
Exposure to visible light, specifically within the wavelength range of 400-500 nm, particularly 400-420 nm, is used to inactivate these bacteria without the need for photosensitizing agents, utilizing a Xenon lamp or LED arrays to achieve bactericidal or bacteriostatic effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photosensitizing agents are used with light to inactivate bacteria, then bacterial inactivation is achieved, but the complexity of the method increases and practical application becomes more difficult
Solution Approach 1:
The patent removes the photosensitizing agent component from the bacterial inactivation system, using light alone (specifically blue light in the 450-495nm range) to achieve bactericidal effects against Gram-positive bacteria. This extraction of the chemical agent simplifies the overall method while maintaining effectiveness.
Solution Approach 2:
The patent identifies and utilizes bacterial porphyrins and other endogenous chromophores as natural light-absorbing intermediaries within the bacteria themselves. These endogenous mediators absorb blue light and generate reactive oxygen species to kill bacteria, eliminating the need for externally applied photosensitizing agents.
2Reliability
If photosensitizing agents are applied to bacteria, then inactivation can occur, but the ease of operation is reduced due to the need for additional application steps
Solution Approach 1:
The bacteria's own endogenous chromophores (porphyrins, flavins, etc.) serve as the light-absorbing agents. The bacteria essentially use their own natural compounds to absorb blue light and initiate the photodynamic killing process, eliminating the need for external application of photosensitizing agents and simplifying the operational procedure.
3Adaptability or versatility
If broad-spectrum light is used for bacterial inactivation, then multiple bacteria types can be targeted, but the precision of wavelength selection decreases
Solution Approach 1:
The patent focuses on a specific wavelength range (450-495nm blue light) that optimally targets the absorption peaks of bacterial porphyrins and other chromophores. This localized wavelength selection provides both precision (targeting specific absorption bands) and versatility (effective against multiple Gram-positive bacteria species that all contain similar endogenous chromophores).
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
This method effectively reduces bacterial counts and inhibits replication, demonstrating significant inactivation of targeted bacteria with minimal impact on human or animal health, suitable for air, surface, and wound disinfection.
Implementation Method 1
Exposure to visible light, specifically within the wavelength range of 400-500 nm, particularly 400-420 nm, is used to inactivate these bacteria without the need for photosensitizing agents, utilizing a Xenon lamp or LED arrays to achieve bactericidal or bacteriostatic effects
Data Source
AI summary
A method for inactivating medically important Gram-positive bacteria including Methicillin-resistant Staphylococcus aureus (MRSA), Coagulase-Negative Staphylococcus (CONS), Streptococcus, Enterococcus and Clostridium species, comprising exposure to visible light, and in particular light within the wavelength range 400-500 nm.