Department of Physics & Astronomy, University of Minnesota, Duluth, Duluth, Minnesota 55812, United States.
Department of Mechanical and Industrial Engineering, University of Minnesota, Duluth, Duluth, Minnesota 55812, United States.
Environ Sci Technol. 2024 Jun 11;58(23):10207-10215. doi: 10.1021/acs.est.3c10028. Epub 2024 May 29.
Plastic pollution, a major environmental crisis, has a variety of consequences for various organisms within aquatic systems. Beyond the direct toxicity, plastic pollution has the potential to absorb biological toxins and invasive microbial species. To better understand the capability of environmental plastic debris to adsorb these species, we investigated the binding of the model protein bovine serum albumin (BSA) to polyethylene (PE) films at various stages of photodegradation. Circular dichroism and fluorescence studies revealed that BSA undergoes structural rearrangement to accommodate changes to the polymer's surface characteristics (i.e., crystallinity and oxidation state) that occur as the result of photodegradation. To understand how protein structure may inform docking of whole organisms, we studied biofilm formation of bacteriaon the photodegraded PE. Interestingly, biofilms preferentially formed on the photodegraded PE that correlated with the state of weathering that induced the most significant structural rearrangement of BSA. Taken together, our work suggests that there are optimal physical and chemical properties of photodegraded polymers that predict which plastic debris will carry biochemical or microbial hitchhikers.
塑料污染是一场主要的环境危机，对水生系统中的各种生物都有多种影响。除了直接毒性之外，塑料污染还有可能吸附生物毒素和入侵的微生物物种。为了更好地了解环境塑料碎片吸附这些物种的能力，我们研究了模型蛋白牛血清白蛋白（BSA）在光降解的不同阶段与聚乙烯（PE）薄膜的结合情况。圆二色性和荧光研究表明，BSA 会发生结构重排，以适应聚合物表面特性（即结晶度和氧化状态）的变化，这些变化是光降解的结果。为了了解蛋白质结构如何影响整个生物体的对接，我们研究了细菌在光降解 PE 上的生物膜形成。有趣的是，生物膜优先在光降解的 PE 上形成，这与诱导 BSA 发生最显著结构重排的风化状态相关。总之，我们的工作表明，光降解聚合物具有预测哪些塑料碎片将携带生化或微生物搭便车者的最佳物理和化学性质。
