TiO₂ as a Nanozyme Mimicking Photolyase to Repair DNA Damage

Abstract

Cyclobutane pyrimidine dimer (CPD) is the most abundant DNA photolesion, and it can be repaired by photolyases based on electron-transfer mechanisms. However, photolyase is absent in the human body and lacks stability for applications. Can one develop natural enzyme mimetics utilizing nanoparticles (termed nanozymes) to mimic photolyase in repairing DNA damage? Herein, we observe the successful reversal of thymine dimer T<>T to normal T base by TiO2 under UVA irradiation. Time-resolved spectroscopy provides direct evidence that the photogenerated electron of TiO2 transfers to T<>T, causing structural instability and initiating the repair process. T–T – would then undergo bond cleavage to form T and T – , and T – returns an electron to TiO2, finishing the photocatalytic cycle. For the first time, TiO2 is discovered to exhibit photocatalytic properties similar to those of natural enzymes, pointing to its extraordinary application potential as a nanozyme to mimic photolyase in repairing DNA damage.

Plant Photocatalysts: Photoinduced Oxidation and Reduction Abilities of Plant Leaf Ashes under Solar Light

“…For instance, we found that adding a small amount of GeO2 powders into the reaction solution signif- There are a wide variety of compounds in the plant leaf ashes; some of them could be potential efficiency photocatalysts. The existence of different ions may also promote photocatalytic activity, as mentioned in the literature [60,61]. Very interestingly, after the washing of the ashes, the decrease in the photodegradation yield proved the promotion roles of soluble ions in ashes (Figure 3).…”