Methods for using rose bengal for detection of chemical warfare agents
Inventors
Owens, Jeffery Ray • McDonald, Rashelle S. • Volkov, Dmytro
Assignees
United States Department of the Air Force
Publication Number
US-10564074-B2
Publication Date
2020-02-18
Expiration Date
2034-10-22
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Abstract
Rose Bengal for detecting a presence of chemical warfare agents. A method of detecting presence of a chemical warfare agent and includes applying a quinoid form of Rose Bengal to a substrate. When the substrate is exposed to the chemical warfare agent, a lactone form of Rose Bengal is spectrally observed because presence of the chemical warfare agent converts the quinoid form to the lactone form of Rose Bengal.
Core Innovation
The invention relates to methods for detecting the presence of chemical warfare agents by applying a quinoid form of Rose Bengal to a substrate. Upon exposure to the chemical warfare agent, the quinoid form converts to a lactone form, which can be spectrally observed. This conformational change causes a visual colorimetric change and a distinct fluorescent signature, enabling detection and monitoring of chemical warfare agents including nerve and blister agents.
The problem addressed is that traditional chemical warfare agent simulants and other contaminants are difficult to detect and decontaminate effectively. Existing decontamination assurance sprays provide only colorimetric feedback and do not decompose contaminants nor indicate the effectiveness of decontamination without reapplication. Thus, there is a need for sprays that both decompose contaminants and provide feedback regarding removal or neutralization.
The invention solves these issues by using Rose Bengal, which is non-toxic, commercially available, and FDA approved for medical uses, possessing chemical properties that neutralize contaminants via photocatalytic oxidation under visible light. The quinoid-to-lactone isomerization provides both a detection mechanism and a means to monitor decomposition. Furthermore, Rose Bengal can be applied neat, cross-linked into fabrics, polymers, coatings, or nanoparticles for enhanced detection, decontamination, and assurance.
Claims Coverage
The claims cover methods of detecting chemical warfare agents using spectral and fluorescent changes of Rose Bengal, with features including dye application techniques, dye combinations, and decontamination mechanisms.
Spectral and fluorescence detection of chemical warfare agents via Rose Bengal conformational change
The method includes acquiring initial absorption and fluorescence spectra of a substrate with quinoid Rose Bengal applied, exposing the substrate to an environment, acquiring subsequent spectra, comparing spectra for decreased absorption between 450 nm and 600 nm and increased fluorescence at 450 nm and/or 485 nm, confirming chemical warfare agent presence if changes occur due to quinoid to lactone isomer conversion.
Use of secondary dyes to enhance detection
Applying a secondary dye such as Rhodamine 560, Rhodamine 640, or both to the substrate before exposure to improve or enable additional detection capabilities alongside Rose Bengal.
Binding Rose Bengal to substrates via functionalization or nanoparticles
Methods of applying Rose Bengal by binding it to substrates using functionalization, encapsulation, trapping, or by binding Rose Bengal to nanoparticles and cross-linking the nanoparticles to the substrate to facilitate stable dye application.
Rose Bengal photocatalytic oxidation for chemical warfare agent decomposition
Decomposing chemical warfare agents on the substrate via a Rose Bengal-induced photocatalytic oxidation mechanism that is enhanced by exposure to visible light.
Use of coated fabrics or polymers containing Rose Bengal and secondary dyes
Providing substrates comprising fabrics, polymers, or both coated with layers containing the quinoid Rose Bengal and secondary dyes, spectrally measuring absorption and fluorescence before and after use time to determine exposure to chemical warfare agents.
The claims comprehensively cover detection of chemical warfare agents via Rose Bengal spectral changes caused by isomerization, the use of secondary dyes to enhance detection, methods of applying and binding these dyes to substrates including nanoparticle incorporation, and simultaneous decomposition of agents through photocatalytic oxidation under visible light.
Stated Advantages
Enables detection of chemical warfare agents through a measurable conformational change in Rose Bengal, providing clear colorimetric and fluorescent signals.
Allows simultaneous decomposition of chemical warfare agents via photocatalytic oxidation under visible light exposure.
Rose Bengal is non-toxic, relatively inexpensive, commercially available, and FDA approved.
Applicable to various substrates including fabrics, polymers, coatings, and nanoparticles for versatile use.
Provides ongoing feedback on contaminant presence and decontamination progress without need for reapplication.
Documented Applications
Detection and monitoring of chemical warfare agents such as nerve agents and blister agents on substrates and assets.
Integration into decontamination assurance sprays that indicate chemical warfare agent presence and decompose contaminants.
Incorporation into coatings, fabrics, polymers, or nanoparticles for self-decontaminating materials and field asset protection.
Use in environmental monitoring to detect chemical warfare agents and evaluate decontamination efficacy.
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