Cyanine Dyes Near-Infrared DNA Photocleavage
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Solution Overview
Problem
Current photodynamic therapy (PDT) agents face limitations in generating reactive oxygen species (ROS) in the near-infrared range due to reduced triplet state energy, limiting their effectiveness for DNA cleavage and cancer treatment, particularly at wavelengths beyond 700 nm.
Innovation Solution
Development of cyanine dyes with specific chemical structures that absorb light in the near-infrared range, enabling efficient singlet oxygen and hydroxyl radical production for DNA cleavage, as demonstrated by compounds with absorption maxima extending to 830 nm and beyond.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If cyanine dyes are designed to absorb light at longer wavelengths (near-infrared range), then tissue penetration depth is improved, but triplet state energy decreases limiting ROS production
Solution Approach 1:
The patent modifies the chemical structure of cyanine dyes by adjusting the polymethine chain length and incorporating specific heterocyclic rings (pyridine, pyrimidine, triazine) to optimize the balance between absorption wavelength and triplet state energy. These parameter changes enable the dyes to maintain sufficient triplet energy for ROS generation while absorbing in the near-infrared range for deep tissue penetration
Solution Approach 2:
The patent creates composite molecular structures combining cyanine dye frameworks with electron-deficient heterocyclic rings. This composite approach allows the molecule to simultaneously achieve long-wavelength absorption (for tissue penetration) and maintained triplet state energy (for ROS production) through electronic interactions between the different molecular components
2Reliability
If cyanine dyes interact strongly with DNA for effective photocleavage, then therapeutic efficacy is improved, but off-target DNA damage in healthy cells increases
Solution Approach 1:
The patent introduces targeting moieties and modifies specific regions of the cyanine dye molecule to enhance selective binding to cancer cell DNA while reducing affinity for healthy cell DNA. This local modification approach allows the dye to concentrate its photocleavage activity specifically in diseased tissues when activated by light
Solution Approach 2:
The patent employs light activation as an intermediary mechanism that controls DNA interaction. The cyanine dyes remain relatively inert until illuminated, at which point they generate ROS that mediate the DNA cleavage effect. This intermediary approach ensures that DNA damage occurs only in the specific location and time of light irradiation, minimizing off-target effects
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 cyanine dyes effectively induce DNA photocleavage and generate ROS in the near-infrared range, enhancing the efficacy of PDT by allowing deeper tissue penetration and improved cancer treatment outcomes.
Implementation Method 1
excitation of a photosensitizer (PS) with low energy light triggers the production of highly localized reactive oxygen species (ROS) in diseased tissues
Implementation Method 2
singlet oxygen (1O2) is generated by Type 2 energy transfer between the triplet excited state (3PS*) of the PS and ground state triplet oxygen (3O2)
Implementation Method 3
The triplet state can also react with 3O2 by Type I electron transfer to yield superoxide anion radicals (O2.-)
Implementation Method 4
DNA interactions are facilitated by the cyanines' two flanking heteroaromatic nitrogen rings, which share a positive charge that is delocalized through a central polymethine bridge
Data Source
AI summary
Disclosed herein are symmetrical and unsymmetrical carbocyanine dyes. Irradiation of the dyes generates reactive species which contribute to DNA damage. The dyes are useful for the treatment of various cancers and cell growth disorders.