Sunlight-enhancing the destruction of biomacromolecules caused by Au and Pb ions through cycling between Au(0) and Au(III)

As exposed to heavy metals, they can bind to biomacromolecules and damage these molecular structures, thereby seriously threatening human's health，for example. Hence, to study the mechanism of interaction between heavy metals and biomacromolecules plays an important role in protecting human health from heavy metal hazards. Here, ssDNA and E. coli lysates were severed as biomacromolecules to analyze their molecular structure changes as exposed to gold (Au) ion and other heavy metal ions, such as Pb 2 + , Cd 2+ , Cr 2+ and Hg 2+ . Gold nanoparticles coated by E. coli lysates (ECL-Au NPs) have been produced in the process of reducing the toxicity of Au(III) by E. coli lysates. As simultaneously exposed to heavy metal ions and sunlight, Au(III) ion can be generated from ECL-Au NPs to rapidly cleave DNA through cycling between Au(0) and Au(III). Meanwhile, the electron transfers also occur in the biomacromolecules from E. coli lysates, and it must cause their structure destruction as well. In conclusion, as exposed to multiple heavy metals, sunlight can enhance the synergetic damage of biomacromolecules by heavy metals. This study provides not only a new tool for DNA cleavage, but also a new mechanism of DNA and proteins damage caused by heavy metal pollution.