Selective Heavy Atom Effect Forming Photosensitizing Hot Spots in Double-Stranded DNA Matrix

Area of Science:

• Biochemistry
• Photochemistry
• Materials Science

Background:

• Triplet exciton formation is crucial for photosensitization in photochemistry and photobiology.
• The heavy atom effect (HAE) enhances triplet exciton yield through external or internal heavy atom incorporation.
• Existing HAE methods lack high selectivity for heavy atom recognition.

Purpose of the Study:

• To introduce a novel heavy atom effect (HAE) mode utilizing a double-stranded DNA (dsDNA) matrix.
• To investigate the cohosting of heavy atoms and photosensitizers within dsDNA for enhanced photochemical properties.
• To demonstrate the selective recognition of heavy atoms by the dsDNA-hosted HAE system.

Main Methods:

• Utilizing dsDNA with thymine (T) or cytosine (C) mismatches to spatially cohost heavy atoms (Hg2+, Ag+) and photosensitizers (dsDNA-staining dyes).
• Employing noncovalent interactions within the dsDNA matrix to achieve close proximity between heavy atoms and photosensitizers.
• Measuring phosphorescence and singlet oxygen (1O2) generation to evaluate the HAE efficiency.

Main Results:

• The dsDNA-hosted HAE significantly enhanced phosphorescence and 1O2 generation from photosensitizers.
• This method achieved highly selective recognition of heavy atoms, surpassing traditional external and internal HAE modes.
• The system demonstrated the effectiveness of spatially adjoined heavy atoms and photosensitizers within a DNA framework.

Conclusions:

• A novel, noncovalent heavy atom effect (HAE) mode has been successfully developed using a dsDNA matrix.
• The dsDNA-hosted HAE offers a simple, efficient, and highly selective method for enhancing photosensitizer performance.
• This approach holds significant potential for applications involving singlet oxygen generation and phosphorescence.