Heptamethine Dyes for Near-Infrared Singlet Oxygen Generation
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Solution Overview
Problem
There is a lack of small molecule near-infrared (NIR) chromophores capable of generating singlet oxygen effectively beyond 800 nm, limiting therapeutic applications that require spatiotemporal control of singlet oxygen generation, particularly in deep tissue areas where visible light penetration is insufficient.
Innovation Solution
Development of heptamethine dyes with orthogonally coupled cationic heteroaryl moieties that absorb NIR light, forming a long-lived charge-transfer state which relaxes to an excited triplet state, enabling efficient singlet oxygen generation when irradiated with NIR light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If small molecule NIR chromophores are used for singlet oxygen generation, then therapeutic applications with spatiotemporal control can be achieved, but effective absorption and singlet oxygen generation beyond 800 nm is not possible
Solution Approach 1:
The patent modifies the molecular parameters of heptamethine dyes by introducing cationic heteroaryl moieties (such as pyridinium, pyrylium, or thiopyrylium rings) at specific positions on the polymethine chain. This structural parameter change extends the absorption spectrum into the 800-1000 nm range while maintaining high singlet oxygen quantum yields, resolving the contradiction between absorption efficiency and singlet oxygen generation capability at these wavelengths.
2Reliability
If visible light is used for singlet oxygen generation, then effective therapy can be achieved, but light penetration in deep tissue areas is insufficient
Solution Approach 1:
The patent changes the optical parameters of the photosensitizing agents by designing heptamethine dyes with absorption maxima in the 800-1000 nm near-infrared range. This parameter change enables deeper tissue penetration (several centimeters) compared to visible light, while the maintained singlet oxygen generation efficiency ensures therapeutic efficacy is preserved at these extended wavelengths.
3Length of stationary object
If two-photon excitation or upconverting nanoparticles are used to achieve NIR singlet oxygen generation, then light penetration can be improved, but molecular simplicity and direct singlet oxygen generation are lost
Solution Approach 1:
The patent extracts the complex mechanisms of two-photon excitation or upconverting nanoparticles and replaces them with a simple organic heptamethine dye molecule that directly absorbs NIR photons and generates singlet oxygen through a single-photon process. This eliminates the need for complex multi-photon equipment or nanoparticle systems while achieving the same therapeutic goal through molecular design alone.
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
These dyes effectively generate singlet oxygen in the NIR range, enhancing therapeutic applications by providing spatiotemporal control and improved light penetration, making them suitable for various medical and industrial uses.
Implementation Method 1
forming a long-lived charge-transfer state which relaxes to an excited triplet state
Implementation Method 2
when irradiated with NIR light
Implementation Method 3
near-infrared absorbing substrates capable of singlet oxygen sensitization
Data Source
AI summary
This current disclosure is directed to charge-transfer heptamethine dyes for NIR singlet oxygen generation, each such dye comprising a near-infrared (NIR) absorbing dye having heptamethine linkages orthogonally coupled to an optionally substituted cationic heteroaryl ring moiety as a charge-transfer partner and uses thereof.