Nondestructive 3D Imaging and Quantification of Hydrated Biofilm-Sediment Aggregates Using X-ray Microcomputed Tomography.
Nondestructive 3D Imaging and Quantification of Hydrated Biofilm-Sediment Aggregates Using X-ray Microcomputed Tomography.
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DOI：
10.1021/acs.est.8b03997
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发表时间：
2018-10
影响因子：
11.4
通讯作者：
Naiyu Zhang;C. Thompson;I. Townend;Kathryn Rankin;D. Paterson;A. Manning
中科院分区：
文献类型：
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作者：
Naiyu Zhang;C. Thompson;I. Townend;Kathryn Rankin;D. Paterson;A. Manning
生物膜-沉积物聚集体（BSA）含有高含水量，其在内部孔隙和通道内或由形成高度水合的生物膜基质的胞外聚合物（EPS）结合。BSA的干燥改变了生物膜形态，从而改变了多孔介质的物理特性，例如BSA内的结合基质和内部孔几何形状。观察天然水合形式的BSA是必不可少的，但由于缺乏成像和识别水合材料的技术而受到阻碍。通常，成像技术（扫描电子显微镜（SEM）、透射电子显微镜（TEM）和聚焦离子束纳米断层扫描（FIB-nt））涉及BSA的干燥（冷冻干燥或丙酮脱水）或防止BSA组分如无机颗粒和孔隙水之间的区分（共聚焦激光扫描显微镜（CLSM））。在这里，我们提出了一种新的方法，同时实现了三维可视化和量化的BSA及其组分在其水合形式在亚微米分辨率使用X射线微计算机断层扫描（μ-CT）。它能够高分辨率检测水合聚集体中多相组分的可比形态：每个单一无机颗粒和水合生物膜基质。这使得聚集体密度的估计和生物膜沉积物结合矩阵的说明。这些信息为调查生物活性物质和聚集体相关沉积物颗粒、污染物（如微塑料）、有机碳的运输及其对水生生物地球化学循环的影响提供了有价值的见解。
Biofilm-sediment aggregate (BSA) contains a high water content, either within internal pores and channels or bound by extracellular polymeric substances (EPS) forming a highly hydrated biofilm matrix. Desiccation of BSAs alters the biofilm morphology and thus the physical characteristics of porous media, such as the binding matrix within BSA and internal pore geometry. Observing BSAs in their naturally hydrated form is essential but hampered due to the lack of techniques for imaging and discerning hydrated materials. Generally, imagery techniques (scanning electron microscopy (SEM), transmission electron microscopy (TEM), and focused ion beam nanotomography (FIB-nt)) involve the desiccation of BSAs (freeze-drying or acetone dehydration) or prevent differentiation between BSA components such as inorganic particles and pore water (confocal laser scanning microscopic (CLSM)). Here, we propose a novel methodology that simultaneously achieves the 3D visualization and quantification of BSAs and their components in their hydrated form at a submicron resolution using X-ray microcomputed tomography (μ-CT). It enables the high-resolution detection of comparable morphology of multiphase components within a hydrated aggregate: each single inorganic particle and the hydrated biofilm matrix. This allows the estimation of aggregate density and the illustration of biofilm-sediment binding matrix. This information provides valuable insights into investigations of the transport of BSAs and aggregate-associated sediment particles, contaminants (such as microplastics), organic carbon, and their impacts on aquatic biogeochemical cycling.