Leibniz Institute of Polymer Research Dresden e.V., Institute of Physical Chemistry and Polymer Physics, Hohe Str. 6, 01069 Dresden, Germany.
Animal Ecology I and BayCEER, University of Bayreuth, 95447 Bayreuth, Germany.
Langmuir. 2022 Jul 26;38(29):8748-8756. doi: 10.1021/acs.langmuir.1c03204. Epub 2022 Jun 23.
The environmental fate and toxicity of microplastic particles are dominated by their surface properties. In the environment, an adsorbed layer of biomolecules and natural organic matter forms the so-called eco-corona. A quantitative description of how this eco-corona changes the particles' colloidal interactions is still missing. Here, we demonstrate with colloidal probe-atomic force microscopy that eco-corona formation on microplastic particles introduces a compressible film on the surface, which changes the mechanical behavior. We measure single particle-particle interactions and find a pronounced increase of long-range repulsive interactions upon eco-corona formation. These force-separation characteristics follow the Alexander-de Gennes (AdG) polymer brush model under certain conditions. We further compare the obtained fitting parameters to known systems like polyelectrolyte multilayers and propose these as model systems for the eco-corona. Our results show that concepts of fundamental polymer physics, like the AdG model, also help in understanding more complex systems like biomolecules adsorbed to surfaces, i.e., the eco-corona.
微塑料颗粒的环境归宿和毒性主要由其表面特性决定。在环境中，生物分子和天然有机物的吸附层形成所谓的生态冠。定量描述这种生态冠如何改变颗粒的胶体相互作用仍然缺失。在这里，我们通过胶体探针原子力显微镜证明，微塑料颗粒上的生态冠形成在表面上引入了可压缩的薄膜，从而改变了力学行为。我们测量了单个颗粒-颗粒相互作用，发现生态冠形成后长程排斥相互作用显著增加。在某些条件下，这些力-分离特征符合亚历山大-德根内（AdG）聚合物刷模型。我们进一步将得到的拟合参数与已知系统（如聚电解质多层）进行比较，并提出这些系统作为生态冠的模型系统。我们的结果表明，像 AdG 模型这样的基础聚合物物理概念也有助于理解更复杂的系统，如吸附在表面上的生物分子，即生态冠。
