Light-activated titanium dioxide crystals could be used to destroy genetic material associated with antibiotic resistance present in water, according to an experimental study published in the scientific journal Chem Catalysis. The approach seeks to address one of the limitations of some disinfection processes: eliminating bacteria without necessarily destroying the DNA that can carry resistance genes.
The research, conducted by an international team led by researchers from Henan University, in China, uses titanium dioxide crystals with small alterations in their structure, known as “oxygen vacancies.” When exposed to light, these sites promote reactions that transform the molecular oxygen present in water into singlet oxygen, a more reactive form of oxygen.
This higher reactivity allows singlet oxygen to attack electron-rich molecules, including the bases that constitute DNA. The oxidation reaction can damage these structures and destroy the genetic information contained in them.
The difference is relevant because some methods used to eliminate microorganisms, including ultraviolet radiation, can inactivate bacteria without completely destroying their genetic material. Extracellular DNA that remains in the water can subsequently be taken up by other microorganisms, potentially contributing to the spread of antibiotic resistance genes.
“The persistence of this genetic material is an environmental concern because extracellular DNA can be taken up by other microorganisms, potentially contributing to the spread of antibiotic resistance,” explains Boxia Liu, from North Minzu University, in China.
In the assays, the researchers placed DNA-related molecules in the water, together with the titanium dioxide catalysts. The crystals were able to completely degrade these molecules, demonstrating the system’s capacity to destroy the compounds used as a model of genetic material.
The technology also presents another difference compared to processes that depend on the continuous addition of oxidants. “Unlike conventional disinfection approaches, which may require the continuous addition of chemical oxidants, this system uses the oxygen naturally available in the environment to disinfect the water,” says Xinjian Shi of Henan University.
However, the researchers emphasize that more studies are needed before this approach can be applied to water treatment. It will be necessary to assess, in particular, its safety for ecosystems and human health, as well as to test the performance of the crystals under real-world conditions, very different from the laboratory experiments conducted so far.
The research thus points to a treatment possibility that seeks not only to eliminate microorganisms present in water but also to reduce the persistence of genetic material that can contribute to the propagation of antibiotic resistance.
