TiO₂ as a Nanozyme Mimicking Photolyase to Repair DNA Damage

Area of Science:

• Biomimetic chemistry
• Nanotechnology
• Photochemistry

Background:

• Cyclobutane pyrimidine dimers (CPDs) are major DNA photolesions.
• Natural photolyases repair CPDs via electron transfer but are unstable and absent in humans.
• Enzyme mimetics using nanoparticles (nanozymes) are sought for DNA repair.

Purpose of the Study:

• To investigate titanium dioxide (TiO2) nanoparticles as nanozymes for DNA repair.
• To explore TiO2's ability to mimic photolyase activity in reversing thymine dimers.

Main Methods:

• Utilized TiO2 nanoparticles and UVA irradiation.
• Employed time-resolved spectroscopy to study the electron transfer mechanism.
• Observed the reversal of thymine dimers (T<>T) to normal thymine (T).

Main Results:

• TiO2 successfully reversed thymine dimers to thymine under UVA light.
• Photogenerated electrons from TiO2 transferred to T<>T, initiating repair.
• A photocatalytic cycle involving electron transfer between TiO2 and the dimer was confirmed.

Conclusions:

• TiO2 nanoparticles exhibit photolyase-like activity, functioning as effective nanozymes.
• This discovery highlights TiO2's potential for applications in DNA damage repair.
• The study establishes a novel biomimetic approach for addressing DNA photolesions.