Dental plaque is a structurally organized biofilm which consists of diverse microbial colonies and extracellular matrix. Its composition may change when pathogenic microorganisms become dominating. Therefore, dental biofilm or plaque has been frequently investigated in the context of oral health and disease. Furthermore, its potential as an alternative matrix for analytical purposes has also been recognized in other disciplines like archeology, food sciences, and forensics. Thus, a careful in-depth characterization of dental plaque is worthwhile. Most of the conducted studies focused on the screening of microbial populations in dental plaque. Their lipid membranes, on the other hand, may significantly impact substance (metabolite) exchange within microbial colonies as well as xenobiotics uptake and incorporation into teeth. Under this umbrella, a comprehensive lipidomic profiling for determination of lipid compositions of in vivo dental plaque samples and of in vitro cultivated biofilm as surrogate matrix to be used for analytical purposes has been performed in this work. An untargeted lipidomics workflow utilizing a ultra-high-performance liquid chromatography (UHPLC)-quadrupole-time-of-flight (QTOF) platform together with comprehensive SWATH (sequential window acquisition of all theoretical fragment ion mass spectra) acquisition and compatible software (MS-DIAL) that comprises a vast lipid library has been adopted to establish an extensive lipidomic fingerprint of dental plaque. The main lipid components in dental plaque were identified as triacylglycerols, followed by cholesterol, cholesteryl esters as well as diacylglycerols, and various phospholipid classes. In vivo plaque is a rare matrix which is usually available in very low amounts. When higher quantities for specific research assays are required, efficient ways to produce an appropriate surrogate matrix are mandatory. A potential surrogate matrix substituting dental plaque was prepared by cultivation of in vitro biofilm from saliva and similarities and differences in the lipidomics profile to in vivo plaque were mapped by statistical evaluation post-analysis. It was discovered that most lipid classes were highly elevated in the in vitro biofilm samples, in particular diacylglycerols, phosphatidylglycerols, and phosphatidylethanolamines (PEs). Furthermore, an overall shift from even-chain lipid species to odd-chain lipids was observed in the cultivated biofilms. On the other hand, even-chain phosphatidylcholines (PCs), lysoPCs, cholesteryl esters, and cholesterol-sulfate were shown to be specifically increased in plaque samples. Graphical abstract.

中文翻译：

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通过非靶向的UHPLC-QTOF-MS / MS和SWATH采集对未矿化的牙菌斑和生物膜进行脂质学分析。

牙菌斑是一种结构上有组织的生物膜，由不同的微生物菌落和细胞外基质组成。当病原微生物占主导地位时，其成分可能会发生变化。因此，在口腔健康和疾病的背景下，经常对牙齿生物膜或牙菌斑进行研究。此外，其作为分析目的的替代矩阵的潜力在考古学，食品科学和法医学等其他学科中也得到了认可。因此，对牙菌斑进行仔细的深入表征是值得的。大多数进行的研究集中于对牙菌斑中微生物种群的筛选。另一方面，它们的脂质膜可能会显着影响微生物菌落内物质（代谢物）的交换以及异生素的吸收和掺入牙齿。在这把伞下 在这项工作中，已经进行了全面的脂质组分析，用于测定体内牙菌斑样品和体外培养的生物膜作为替代基质的脂质组成。使用超高效液相色谱（UHPLC）-四极杆飞行时间（QTOF）平台以及全面的SWATH（所有理论碎片离子质谱的顺序窗口采集）采集和兼容软件（MS）的非靶向脂质组学工作流程-DIAL）（包括一个巨大的脂质库）已被采用来建立广泛的牙菌斑脂质组学指纹。牙菌斑中的主要脂质成分被确定为三酰基甘油，其次是胆固醇，胆固醇酯，二酰基甘油和各种磷脂。体内噬菌斑是一种罕见的基质，通常可以以非常低的量获得。如果需要更多的量用于特定的研究分析，则必须使用有效的方法来生成适当的替代矩阵。通过从唾液中培养体外生物膜来制备潜在的替代牙斑的替代基质，并通过分析后的统计学评估绘制脂质组学与体内斑块的相似性和差异。发现在体外生物膜样品中大多数脂质类别高度升高，特别是二酰基甘油，磷脂酰甘油和磷脂酰乙醇胺（PEs）。此外，在培养的生物膜中观察到了从偶数链脂质种类到奇数链脂质的总体转变。另一方面，偶数链磷脂酰胆碱（PCs），lysoPCs，胆固醇酯，胆固醇样品中的胆固醇和硫酸盐显示出斑块样品中的特异性增加。图形概要。