Abstract：
In urbanized areas, extracellular DNA (exDNA) is suspected of carrying genes with undesirable traits like virulence genes (VGs) or antibiotic resistance genes (ARGs), which can spread through horizontal gene transfer (HGT). Hence, it is crucial to develop novel approaches for the mitigation of exDNA in the environment. Our research explores the role of goethite, a common iron mineral with high adsorption capabilities, in exDNA adsorption processes. We compare well-crystalline, semi-crystalline, and nano goethites with varying particle sizes to achieve various specific surface areas (SSAs) (18.7-161.6 m2/g) and porosities. We conducted batch adsorption experiments using DNA molecules of varying chain lengths (DNA sizes: <11 Kb, <6 Kb, and <3 Kb) and assessed the impact of Ca2+ and biomacromolecules on the adsorption efficacy and mechanisms. Results show that porosity and pore structure significantly influence DNA adsorption capacity. Goethite with well-developed meso- and macroporosity demonstrated enhanced DNA adsorption. The accumulation of DNA on the goethite interface led to substantial aggregation in the system, thus the formation of DNA-goethite conjugates, indicating the bridging between mineral particles. DNA chain length, the presence of Ca2+, and the biomacromolecule matrix also affected the adsorption capacity and mechanism. Interactions between DNA and positively charged biomacromolecules or Ca2+ led to DNA compaction, allowing greater DNA accumulation in pores. However, a high concentration of biomacromolecules led to the saturation of the goethite surface, inhibiting DNA adsorption. AFM imaging of goethite particles after adsorption suggested the formation of the DNA multilayer. The study advances understanding of the environmental behavior of exDNA and its interaction with iron oxyhydroxides, offering insights into developing more effective methods for ARGs removal in wastewater treatment plants. By manipulating the textural properties of goethite, it\'s possible to enhance exDNA removal, potentially reducing the spread of biocontamination in urban and industrial environments.
摘要：
在城市化地区,细胞外DNA（exDNA）被怀疑携带具有不良性状的基因，如毒力基因（VGs）或抗生素抗性基因（ARGs），可以通过水平基因转移（HGT）传播。因此，开发新的方法来缓解环境中的exDNA是至关重要的。我们的研究探讨了针铁矿的作用，一种具有高吸附能力的常见铁矿物，在exDNA吸附过程中。我们比较结晶，半结晶,和不同粒径的纳米针铁矿，以实现各种比表面积（SSA）（18.7-161.6m2/g）和孔隙率。我们使用不同链长的DNA分子（DNA大小：<11Kb，<6Kb,和<3Kb），并评估了Ca2和生物大分子对吸附效率和机理的影响。结果表明，孔隙度和孔结构显著影响DNA吸附能力。具有发达的中孔和大孔的针铁矿表现出增强的DNA吸附。DNA在针铁矿界面上的积累导致了系统中的大量聚集，从而形成DNA-针铁矿结合物，表明矿物颗粒之间的桥接。DNA链长度,Ca2+的存在，生物大分子基质也影响吸附能力和机理。DNA和带正电荷的生物大分子或Ca2+之间的相互作用导致DNA压缩，允许更多的DNA在毛孔中积累。然而,高浓度的生物大分子导致针铁矿表面饱和，抑制DNA吸附。吸附后的针铁矿颗粒的AFM成像表明了DNA多层的形成。这项研究促进了对exDNA的环境行为及其与羟基氧化铁的相互作用的理解，为在污水处理厂中开发更有效的去除ARGs的方法提供见解。通过操纵针铁矿的纹理特性，有可能增强exDNA去除，有可能减少城市和工业环境中生物污染的传播。
