Bhagwat Geetika, O'Connor Wayne, Grainge Ian, Palanisami Thava
School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, Australia.
NSW Department of Primary Industries, Port Stephens Fisheries Institute, Taylors Beach, NSW, Australia.
Front Microbiol. 2021 Jun 25;12:687118. doi: 10.3389/fmicb.2021.687118. eCollection 2021.
Conditioning films (CFs) are surface coatings formed by the adsorption of biomolecules from the surrounding environment that can modify the material-specific surface properties and precedes the attachment of microorganisms. Hence, CFs are a biologically relevant identity that could govern the behavior and fate of microplastics in the aquatic environment. In the present study, polyethylene terephthalate (PET) and polylactic acid (PLA) plastic cards were immersed in natural seawater to allow the formation of CFs. The changes in the surface roughness after 24 h were investigated by atomic force microscopy (AFM), and the surface changes were visualized by scanning electron microscopy (SEM). The global elemental composition of the conditioned surface was investigated by energy dispersive spectroscopy (EDS). Results indicated that marine conditioning of PET and PLA samples for 24 h resulted in an increase of ∼11 and 31% in the average surface roughness, respectively. SEM images revealed the attachment of coccoid-shaped bacterial cells on the conditioned surfaces, and the accumulation of salts of sodium and phosphate-containing precipitates was revealed through the EDS analysis. The results indicate that the increase in surface roughness due to conditioning is linked to a material's hydrophilicity leading to a rapid attachment of bacteria on the surfaces. Further investigations into the CFs can unfold crucial knowledge surrounding the plastic-microbe interaction that has implications for medical, industrial, and environmental research.
调理膜（CFs）是由周围环境中的生物分子吸附形成的表面涂层，它可以改变材料特定的表面性质，并先于微生物附着。因此，CFs是一种与生物学相关的特性，它可以控制微塑料在水生环境中的行为和归宿。在本研究中，将聚对苯二甲酸乙二酯（PET）和聚乳酸（PLA）塑料卡片浸入天然海水中以形成CFs。通过原子力显微镜（AFM）研究24小时后表面粗糙度的变化，并通过扫描电子显微镜（SEM）观察表面变化。通过能量色散光谱（EDS）研究调理后表面的整体元素组成。结果表明，PET和PLA样品在海水中调理24小时后，平均表面粗糙度分别增加了约11%和31%。SEM图像显示了球状细菌细胞附着在调理后的表面上，通过EDS分析揭示了含钠和含磷酸盐沉淀物的积累。结果表明，调理导致的表面粗糙度增加与材料的亲水性有关，从而导致细菌在表面快速附着。对CFs的进一步研究可以揭示围绕塑料 - 微生物相互作用的关键知识，这对医学、工业和环境研究具有重要意义。
