Covalently Platinated DNA Oligonucleotides as Ratiometric Dioxygen Sensors.

Area of Science:

• Biochemistry
• Materials Science
• Nanotechnology

Background:

• Functional nucleic acids are crucial in various biological processes.
• Developing artificial nucleobases expands the capabilities of nucleic acid-based technologies.
• Platinum(II) complexes offer unique photophysical properties for molecular sensing.

Purpose of the Study:

• To covalently attach phosphorescent platinum(II) complexes to DNA oligonucleotides.
• To investigate the impact of linker length on duplex stability and photoluminescence.
• To develop a novel ratiometric dioxygen sensor based on platinated DNA.

Main Methods:

• Covalent attachment of platinum(II) complexes to DNA via deoxyribose using different linkers.
• Formation and characterization of DNA duplexes with canonical nucleobases.
• Analysis of photoluminescence spectra to detect Pt-Pt interactions and dioxygen presence.
• Cellular transfection to assess biocompatibility and degradation.

Main Results:

• Stable DNA duplexes were formed, with guanine yielding the highest stability.
• Pt-Pt interactions were observed in adjacent platinum(II) complex placements, leading to excimeric luminescence.
• The ratio of monomeric to excimeric emission correlated with linker length and dioxygen levels.
• The platinated oligonucleotide demonstrated ratiometric dioxygen sensing capabilities.
• The oligonucleotide showed low toxicity but degraded in cells, necessitating further modification.

Conclusions:

• Phosphorescent platinum(II) complexes can be integrated into DNA as artificial nucleobases.
• Platinated oligonucleotides can serve as effective ratiometric dioxygen sensors.
• Further research is needed to enhance stability for intracellular applications.