Perez-Sanchez Emiliano, Martínez Ana
Departamento de Materiales de Baja Dimensionalidad. Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Coyoacan, Mexico City, Mexico.
PLoS One. 2025 Aug 20;20(8):e0330708. doi: 10.1371/journal.pone.0330708. eCollection 2025.
Microplastics and nanoplastics are everywhere, but little is known about their chemical reactivity. In this study we performed a Density Functional Theory study of polystyrene (PS, a common non-biodegradable thermoplastic polymer) and polylactic acid (PLA, a biodegradable polymer) to understand the capacity to react of these two nanoplastics. The chemical reactivity of these oligomers is investigated through their capacity to either donate or accept electrons and, therefore, their capacity to oxidize other molecules. To model nanoplastics, we used oligomers formed with different numbers of carbon atoms. PLA is a better electron acceptor than PS, which could be related to oxidation reactions. It has also been reported that the presence of micro- and nanoplastics in the environment increases the bioaccumulation of pharmaceuticals such as antibiotics. To investigate this idea, we calculated the interaction energies of PLA and PS oligomers with two antibiotics: ciprofloxacin and metronidazole. The results indicate that both can form stable compounds with these two antibiotics. This might be related to the Trojan horse effect, which refers to the idea that the presence of nanoplastics increases the bioaccumulation of drugs. These results contribute to understand the reactivity of these nanoplastics.
微塑料和纳米塑料无处不在，但人们对它们的化学反应性却知之甚少。在本研究中，我们对聚苯乙烯（PS，一种常见的不可生物降解热塑性聚合物）和聚乳酸（PLA，一种可生物降解聚合物）进行了密度泛函理论研究，以了解这两种纳米塑料的反应能力。通过这些低聚物给出或接受电子的能力，进而通过它们氧化其他分子的能力，来研究这些低聚物的化学反应性。为了模拟纳米塑料，我们使用了由不同碳原子数形成的低聚物。PLA比PS是更好的电子受体，这可能与氧化反应有关。据报道，环境中微塑料和纳米塑料的存在会增加抗生素等药物的生物累积。为了研究这一观点，我们计算了PLA和PS低聚物与两种抗生素：环丙沙星和甲硝唑之间的相互作用能。结果表明，这两种抗生素都能与这两种低聚物形成稳定的化合物。这可能与“特洛伊木马”效应有关，“特洛伊木马”效应指的是纳米塑料的存在会增加药物的生物累积这一观点。这些结果有助于理解这些纳米塑料的反应性。
