Thio-substituted Nucleobases for Deep-Tissue Photodynamic Therapy
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Solution Overview
Problem
Current photodynamic therapy (PDT) methods for treating cancer and other conditions face limitations in depth penetration and efficacy due to the absorption characteristics of existing photosensitizers, which restrict their application to superficial tissues and require multiple treatments.
Innovation Solution
Development of dithio-substituted pyrimidine and purine nucleobases, nucleosides, and nucleotides that absorb light in the ultraviolet-A to infrared region, allowing for deeper tissue penetration and inducing photochemical reactions for targeted cell death upon exposure to electromagnetic radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If conventional photosensitizers are used in PDT, then the therapy can be applied to superficial dermatological malignancies, but the treatment depth is limited and cannot effectively treat internal or deep-seated cancer cells
Solution Approach 1:
The patent modifies the chemical structure of photosensitizers by introducing thio-substitution at specific positions (2-thio, 4-thio, or 2,4-dithio substitutions on pyrimidine rings) to alter their absorption spectra. This structural parameter change enables the photosensitizers to absorb light at wavelengths that penetrate deeper into tissues, thereby extending treatment depth while maintaining photochemical efficacy for generating reactive oxygen species.
2Reliability
If multiple PDT treatments are administered to achieve therapeutic effect, then the treatment efficacy can be improved, but the treatment time and patient burden increase
Solution Approach 1:
The thio-substituted photosensitizers exhibit enhanced molar absorptivity and improved quantum yields for singlet oxygen generation compared to conventional photosensitizers. These parameter improvements allow for more efficient photochemical reactions during each treatment session, potentially achieving therapeutic effects in fewer treatments and reducing overall treatment time.
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 dithio-substituted compounds achieve deeper tissue treatment and enhanced photochemical reaction efficacy, facilitating more effective localized cell death and injury, thereby improving the therapeutic outcomes for various cancers and inflammatory conditions.
Implementation Method 1
Development of dithio-substituted pyrimidine and purine nucleobases, nucleosides, and nucleotides that absorb light in the ultraviolet-A to infrared region, allowing for deeper tissue penetration
Implementation Method 2
Following the absorption of light energy, the excited photosensitizer can either directly react with a biomolecule (Type I photosensitization) or it can transfer its energy to molecular oxygen. Energy transfer to molecular oxygen forms highly reactive oxygen species, such as singlet oxygen, which can then go on to damage biomolecules (Type II photosensitization).
Data Source
AI summary
A method of using a compound in a phototherapy procedure includes administering to a subject in need of treatment a therapeutically effective amount of a thio-substituted nucleobase, nucleoside, nucleotide, and/or analogs thereof; and exposing the administered compound to electromagnetic radiation.